Vaccines

19 pages, 2288 KiB

Open AccessArticle

Construction of the First Russian Recombinant Live Attenuated Vaccine Strain and Evaluation of Its Protection Efficacy Against Two African Swine Fever Virus Heterologous Strains of Serotype 8

by Andrey Koltsov, Mikhail Sukher, Sergey Krutko, Sergey Belov, Alexey Korotin, Sofia Rudakova, Sergey Morgunov and Galina Koltsova

Vaccines 2024, 12(12), 1443; https://doi.org/10.3390/vaccines12121443 (registering DOI) - 21 Dec 2024

Abstract

Background/Objectives: The spread of African swine fever virus (ASFV) has led to major economic losses to pork worldwide. In Russia, there are no developed or registered vaccines against ASFV genotype II, which is associated with numerous ASFV outbreaks in populations of domestic pigs [...] Read more.

Background/Objectives: The spread of African swine fever virus (ASFV) has led to major economic losses to pork worldwide. In Russia, there are no developed or registered vaccines against ASFV genotype II, which is associated with numerous ASFV outbreaks in populations of domestic pigs and wild boars in the country. Methods: We introduced deletions of the six MGF360 and MGF505 genes of the ASFV virulent Stavropol_01/08 strain, isolated in Russia in 2008. Results: We show here that this deletion did lead to full attenuation of the ASFV virulent Stavropol_01/08 strain. Animals intramuscularly inoculated with 10⁴ HAD₅₀ of ΔMGF360/505_Stav developed a strong immune response and short period of viremia (at 3–7 days post-inoculation). Recombinant ΔMGF360/505_Stav strain provides complete protection of pigs against the ASFV parental Stavropol_01/08 strain (10³ HAD₅₀). Therefore, in our experiment, we did not detect the genome of both the virulent and the recombinant strains in the blood and organs post-challenge with the Stavropol_01/08. In contrast, we found only partial protection (40%) of the ΔMGF360/505_Stav-immunized pigs against challenge with the ASFV heterologous Rhodesia strain. Additionally, the surviving animals had a prolonged fever, and their condition was depressed for most of the experiment. Conclusions: Thus, the ASFV recombinant ΔMGF360/505_Stav strain is the first live attenuated vaccine (LAV) in Russia that induces complete protection in pigs challenged with the highly virulent, epidemiologically relevant strains genotype II and serotype 8. However, this ASF LAV is not able to provide a high level of protection against other variants of serotype 8. Full article

(This article belongs to the Special Issue Vaccine Development for Swine Viral Pathogens)

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14 pages, 272 KiB

Open AccessArticle

A Qualitative Analysis of Rural Community Vaccination Barriers During the COVID-19 Pandemic

by Kimberly C. McKeirnan, Megan R. Undeberg, Skylar Zelenko and Ghazal Meratnia

Vaccines 2024, 12(12), 1442; https://doi.org/10.3390/vaccines12121442 (registering DOI) - 21 Dec 2024

Abstract

Background/Objectives: Rural communities in the United States experience increased disparity of care for both general healthcare services and access to routine vaccines. Previous research has indicated a 40% lower vaccination rate in rural communities, as compared to urban counterparts. Having a better understanding [...] Read more.

Background/Objectives: Rural communities in the United States experience increased disparity of care for both general healthcare services and access to routine vaccines. Previous research has indicated a 40% lower vaccination rate in rural communities, as compared to urban counterparts. Having a better understanding regarding factors influencing lower vaccination rates in rural areas could help public health officials prepare for future vaccination efforts. This research sought to gather and evaluate the opinions of people who live and work in rural areas regarding barriers to COVID-19 vaccine uptake. Methods: A semi-structured qualitative key informant interview design was utilized by researchers to gather opinions from university Extension staff in Washington State. Interview transcripts were analyzed using the Theory of Planned Behavior (ToPB) framework to evaluate COVID-19 vaccination-related intentions and motivational factors that the Extension staff observed among rural populations in their communities. Results: Twenty-one participants representing 34 out of the 40 Extension offices responded and were interviewed during fall 2023. Using the ToPB constructs, nine barriers were identified. Attitude-related barriers included the following: inherent social distancing in rural location negating vaccine necessity; lack of early vaccine availability in rural locales; concerns regarding ineffectiveness of the vaccine; and inadequate dissemination of vaccine information to non-English language speakers and those with limited access to technology. Subjective norm barriers included the following: perception of exclusion of rural populations’ unique needs during design and implementation of vaccine mandates; exertion of social pressures on rural individuals’ vaccine uptake decision; and highly visible breakdown in standard trust in core community institutions and leadership. Barriers related to loss of perceived behavioral control included vaccine mandates impacting self-perceived loss of autonomy and limitations in vaccine technology information impacting perception of vaccine safety. Conclusions: By identifying barriers to vaccination in rural communities during the COVID-19 pandemic, future outreach efforts can be designed to improve intention and lead to stronger vaccination uptake. Full article

(This article belongs to the Special Issue Infectious Diseases: Importance for Public Health, Epidemiology, Promoting Factors, and Vaccines Prevention)

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10 pages, 1113 KiB

Open AccessPerspective

Challenges and Opportunities for Adult Vaccine Coverage: Insights for Healthcare Professionals Focusing on Herpes Zoster in Mexico

by María Yolanda Cervantes-Apolinar, Adriana Guzman-Holst, Abiel Mascareñas De los Santos, Alejandro Ernesto Macías Hernández, Álvaro Cabrera, Argelia Lara-Solares, Carlos Abud Mendoza, Daniel Motola Kuba, Diana Fabiola Flores Díaz, Fernanda Salgado Gomez, Graciela-Elia Castro Narro, Javier Nieto, José Antonio Mata-Marín, José Fernando Barba Gómez, Juan Carlos Tinoco, Juan Manuel Calleja Castillo, Maria Margarita Contreras Serratos, Nathali Castellanos Ramos, Oscar Rosas Carrasco, Raúl Ricaño and Gloria C. Huerta García Show full author list Hide full author list

Vaccines 2024, 12(12), 1441; https://doi.org/10.3390/vaccines12121441 (registering DOI) - 21 Dec 2024

Abstract

Herpes zoster (HZ) is a common disease in older adults and immunocompromised patients, and is frequently associated with long-term complications that impact quality of life. Fortunately, more than one vaccine against HZ is now available in Mexico. Two expert consensus groups discussed adult [...] Read more.

Herpes zoster (HZ) is a common disease in older adults and immunocompromised patients, and is frequently associated with long-term complications that impact quality of life. Fortunately, more than one vaccine against HZ is now available in Mexico. Two expert consensus groups discussed adult vaccination strategies in Mexico, focusing on HZ in older adults and immunocompromised individuals; their insights are reported here. HZ is usually treated inappropriately in Mexico. Late diagnosis and suboptimal management are common, as is a lack of treatment options, particularly for pain, which is often unresponsive to standard painkillers. Improving vaccination rates against HZ in Mexico is therefore important, but several barriers to HZ vaccination exist. It is not included in the national vaccination schedule, where included vaccines usually have higher coverage. Actions to overcome barriers include improving awareness of HZ and vaccine availability, developing and promoting guidelines and recommendations for vaccination, and expanding access and infrastructure for vaccination. Full article

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21 pages, 6847 KiB

Open AccessArticle

Enhanced Immune Response Against Echinococcus Granulosus Through a CTLA-4/B7 Affinity-Based Vaccine

by Yuejie Zhu, Yueyue He, Ziyue Yin, Na Chen, Xingxing Qi, Jianbing Ding, Yujiao Li and Fengbo Zhang

Vaccines 2024, 12(12), 1440; https://doi.org/10.3390/vaccines12121440 (registering DOI) - 20 Dec 2024

Abstract

Background: Echinococcosis is a zoonotic infectious disease that poses a significant threat to the health of individuals living in rural regions. While vaccination represents a potential strategy for disease prevention, there is currently no effective vaccine available for humans to prevent cystic echinococcosis [...] Read more.

Background: Echinococcosis is a zoonotic infectious disease that poses a significant threat to the health of individuals living in rural regions. While vaccination represents a potential strategy for disease prevention, there is currently no effective vaccine available for humans to prevent cystic echinococcosis (CE). This study aimed to design a novel multi-epitope vaccine (MEV) against Echinococcus granulosus for human use, employing immunoinformatics methods. Methods: We identified core epitopes from two key antigens, EgA31 and EgG1Y162, and integrated them into the immunoglobulin variable region of CTLA-4 (CTLA-4lgV) to create the CVE31-162 vaccine construct. The secondary and tertiary structures of the CVE31-162 were established using bioinformatics methods. The interaction between the CVE31-162 and B7 molecules was assessed through molecular dynamics simulations. Finally, both in vitro and in vivo experiments were conducted to validate the effectiveness of the CVE31-162 against the immunological effects of Echinococcus granulosus. Results: Bioinformatics analysis indicated that CVE31-162 exhibits favorable antigenicity, stability, and non-allergenicity. Furthermore, CVE31-162 demonstrated a stable three-dimensional structural model. Molecular docking (MD) and molecular dynamics simulations (MDS) revealed a strong binding affinity between CVE31-162 and B7 molecules. Immune simulation results suggested that the vaccine elicits robust humoral and cell-mediated immune responses. Both in vitro and in vivo experiments demonstrated that immunized mice exhibited significantly elevated levels of antigen-specific antibodies and enhanced lymphocyte proliferation compared to the control group. Conclusions: CVE31-162, which is based on the interaction between CTLA-4 and B7, represents a promising multi-epitope vaccine for Echinococcus granulosus. Full article

(This article belongs to the Special Issue Human Immune Responses to Infection and Vaccination)

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19 pages, 644 KiB

Open AccessReview

Treatment and Prevention of HPV-Associated Skin Tumors by HPV Vaccination

by Thomas Meyer and Eggert Stockfleth

Vaccines 2024, 12(12), 1439; https://doi.org/10.3390/vaccines12121439 (registering DOI) - 20 Dec 2024

Abstract

HPV-associated dermatological diseases include benign lesions like cutaneous warts and external genital warts. In addition, HPV infection is associated with the development of epithelial skin cancers, in particular cutaneous squamous cell carcinoma (cSCC). In contrast to anogenital and oropharyngeal cancers caused by mucosal [...] Read more.

HPV-associated dermatological diseases include benign lesions like cutaneous warts and external genital warts. In addition, HPV infection is associated with the development of epithelial skin cancers, in particular cutaneous squamous cell carcinoma (cSCC). In contrast to anogenital and oropharyngeal cancers caused by mucosal HPV types of genus alpha papillomavirus, cSCC-associated HPV types belong to the genus beta papillomavirus. Currently available HPV vaccines that target mucosal HPV types associated with anogenital cancer and genital warts are type-specific and provide no cross-protection against beta HPV. When implementing vaccination to beta HPV to prevent skin tumors, it must be considered that acquisition of these HPV types occurs early in childhood and that the risk for cSCC increases with growing age and decreasing immune surveillance. Thus, individuals considered for beta HPV vaccination usually have pre-existing infection and are largely immunocompromised. On the other hand, worldwide increasing incidence rates of epithelial skin cancer reflect an urgent need for skin cancer prevention measures. Based on the pathogenic involvement of beta HPV, vaccination may represent a promising prevention strategy. Indeed, various procedures of prophylactic and therapeutic vaccination have been developed, and some of them have shown efficiency in animal models. Thus far, however, none of these vaccine candidates has been approved for application in humans. Full article

(This article belongs to the Section Human Papillomavirus Vaccines)

23 pages, 807 KiB

Open AccessSystematic Review

Effectiveness of General Practitioners’ Involvement in Adult Vaccination Practices: A Systematic Review and Meta-Analysis of International Evidence

by Andrea Ceccarelli, Gabriele Munafò, Francesco Sintoni, Christian Cintori, Davide Gori and Marco Montalti

Vaccines 2024, 12(12), 1438; https://doi.org/10.3390/vaccines12121438 - 20 Dec 2024

Abstract

Background: General practitioners (GPs) and primary care units collaborate with Prevention Departments (PDs) to improve immunization by participating in vaccination campaigns, sharing tools, and implementing educational programs to raise patient awareness. This review aimed to identify effective strategies for involving GPs in PD [...] Read more.

Background: General practitioners (GPs) and primary care units collaborate with Prevention Departments (PDs) to improve immunization by participating in vaccination campaigns, sharing tools, and implementing educational programs to raise patient awareness. This review aimed to identify effective strategies for involving GPs in PD vaccination practices. Methods: A systematic review following PRISMA guidelines was conducted on MEDLINE, TripDatabase, ClinicalTrials, CINAHL, and Cochrane up to January 2024 to identify full-text studies in English evaluating the effectiveness of GP involvement. A meta-analysis was also performed. Results: Of 1018 records, 15 studies were included, with an intermediate quality assessment. Studies originated from the United States (n = 9), Europe (5), Singapore (1), and China (1). Eight studies investigated educational programs for GPs, while seven focused on organizational or technological interventions to enhance immunization practices. Twelve studies reported increased vaccine uptake after intervention. Vaccines addressed included influenza, SARS-CoV-2, pneumococcal, zoster, and trivalent (diphtheria, tetanus, pertussis). Interventions involving GPs in PD vaccination campaigns, focusing on organizational or technological strategies, demonstrated a significant increase in vaccine uptake (OR = 1.15; 95% CI: 1.03–1.27; p < 0.0001; I² = 96%). Conclusions: GPs emerged as valuable allies for PDs due to their extensive territorial reach and trusted relationships with patients. Additionally, up-to-date organizational and technological tools could play a decisive role in increasing vaccine uptakes. This study, offering valuable insights into the effectiveness of GPs involvement, may be useful to implement similar intervention in different contexts. Full article

(This article belongs to the Special Issue Health Technology Assessment of Vaccination: Strategies, Public Health and Values)

14 pages, 628 KiB

Open AccessArticle

A Psychosocial Critique of the Consequences of the COVID-19 Pandemic on UK Care Home Staff Attitudes to the Flu Vaccination: A Qualitative Longitudinal Study

by Adaku Anyiam-Osigwe, Thando Katangwe-Chigamba, Sion Scott, Carys Seeley, Amrish Patel, Erika J. Sims, Richard Holland, Veronica Bion, Allan B. Clark, Alys Wyn Griffiths, Liz Jones, Adam P. Wagner, David J. Wright and Linda Birt

Vaccines 2024, 12(12), 1437; https://doi.org/10.3390/vaccines12121437 (registering DOI) - 20 Dec 2024

Abstract

Background/Objectives: Vaccinating care home staff is essential to protect vulnerable residents by reducing infection risks and creating a safer care environment. However, vaccine hesitancy amongst staff remains a challenge, particularly since the COVID-19 pandemic raised concerns about side effects and vaccination mandates. This [...] Read more.

Background/Objectives: Vaccinating care home staff is essential to protect vulnerable residents by reducing infection risks and creating a safer care environment. However, vaccine hesitancy amongst staff remains a challenge, particularly since the COVID-19 pandemic raised concerns about side effects and vaccination mandates. This study examines how the pandemic influenced flu vaccine hesitancy amongst UK care home staff. Methods: Data were collected from the FluCare trials conducted over the 2021–22 and 2022–23 winter seasons to explore the impact of concurrent mandatory and non-mandatory COVID-19 vaccination policies on flu vaccine uptake. A total of 52 interviews (21 from the feasibility study and 31 from the randomised control trial) were conducted with care home managers and staff. Thematic analysis identified key themes shaping staff attitudes toward flu vaccination. Results: Four central themes emerged regarding the impact of the pandemic on staff attitudes and the contextual influences shaping vaccine hesitance: (i) tension between autonomy and morals in vaccination decisions; (ii) the COVID ‘craze’ and the displacement of the flu vaccine; (iii) the role of the COVID ‘craze’ in staff vaccine fatigue; and (iv) conspiracies, (mis)information, and the significance of trust. Psychosocial theories on decision making and health behaviour were used to further interpret the findings. Conclusions: Our findings suggest that post-COVID-19 interventions in care home setting should address the issues of autonomy, vaccine fatigue, and trust to enhance vaccine uptake. Understanding these factors could support more effective strategies to address hesitancy amongst care home staff in future vaccination campaigns. Full article

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17 pages, 818 KiB

Open AccessPerspective

Platform Technology in Global Vaccine Regulation: Development, Applications, and Regulatory Strategies with Insights from China

by Xiaojing Li, Su Jin, Shuyang Guo, Dan Yang, Wenbo Sai, Xiao Qiu, Xin Zhao, Lan Wang, Tao Wang and Min Li

Vaccines 2024, 12(12), 1436; https://doi.org/10.3390/vaccines12121436 - 20 Dec 2024

Abstract

The concept of “platform technology” gained prominence after the Ebola outbreak and since then has become essential to international vaccine (prophylactic vaccines against infectious disease) regulatory frameworks. Its significance was further amplified during the COVID-19 pandemic, where platform technology enabled the rapid development [...] Read more.

The concept of “platform technology” gained prominence after the Ebola outbreak and since then has become essential to international vaccine (prophylactic vaccines against infectious disease) regulatory frameworks. Its significance was further amplified during the COVID-19 pandemic, where platform technology enabled the rapid development and approval of vaccines, optimizing regulatory processes, and enhancing global public health responses. As a transformative tool, platform technology streamlines product development, allowing for the reduction in the number of clinical trials or exemption from certain clinical trials and facilitating cross-referencing in regulatory submissions. Despite significant efforts to establish standardized regulatory procedures, challenges remain, particularly in achieving a unified definition and application of platform technology across regions. This paper explores the evolution, applications, and regulatory strategies of platform technology, with a focus on China’s experience in this field. China’s approach, encompassing risk assessment, and the expedited approval of emergency vaccines, offers valuable insights into global regulatory coordination. By analyzing China’s regulatory contributions and international practices, this paper highlights the potential of platform technology to address future pandemics, including “Pathogen X”, and underscores the importance of harmonizing global regulatory efforts to strengthen public health preparedness and response. Full article

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9 pages, 593 KiB

Open AccessArticle

Plant Cell Culture-Derived Saponin Adjuvant Enhances Immune Response Against a Stabilized Human Metapneumovirus Pre-Fusion Vaccine Candidate

by Maarten Swart, Jessica Allen, Brendan Reed, Ana Izquierdo Gil, Johan Verspuij, Sonja Schmit-Tillemans, Anish Chakkumkal, Mark Findeis, Angela V. Hafner, Chandresh Harjivan, Rebecca Kurnat, Harmjan Kuipers, Roland Zahn and Boerries Brandenburg

Vaccines 2024, 12(12), 1435; https://doi.org/10.3390/vaccines12121435 - 20 Dec 2024

Abstract

Human metapneumovirus (HMPV) is a significant respiratory pathogen, particularly in vulnerable populations. Background: No vaccine for the prevention of HMPV is currently licensed, although several subunit vaccines are in development. Saponin-based adjuvant systems (AS), including QS-21, have transformed the field of subunit vaccines [...] Read more.

Human metapneumovirus (HMPV) is a significant respiratory pathogen, particularly in vulnerable populations. Background: No vaccine for the prevention of HMPV is currently licensed, although several subunit vaccines are in development. Saponin-based adjuvant systems (AS), including QS-21, have transformed the field of subunit vaccines by dramatically increasing their potency and efficacy, leading to the development of several licensed vaccines. However, naturally sourced tree bark-extracted QS-21 faces supply and manufacturing challenges, hindering vaccine development. Objective: This study reports on an alternative plant cell culture system for the consistent production of highly pure QS-21. Method: We evaluated the efficacy of cultured plant cell (cpc)-produced QS-21 in a novel HMPV vaccine, formulating a recombinant pre-fusion stabilized HMPV F protein (preF) with cpcQS-21 and a synthetic toll-like receptor 4 (TLR4) agonist adjuvant formulation. Results: In mice, TLR4 agonist containing adjuvant formulations with plant cell-produced QS-21 performed equally to licensed adjuvant AS01 containing tree-bark-extracted QS-21 and demonstrated a significant increase in immunogenicity against HMPV preF compared to the unadjuvanted control. Conclusion: Our findings pave the way for a reliable, scalable, and sustainable source of pure QS-21, enabling the development of highly effective HMPV and other vaccines with significant public health impact. Full article

(This article belongs to the Section Vaccine Adjuvants)

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13 pages, 2176 KiB

Open AccessArticle

Vaccination Coverage at Birth in Brazil: Spatial and Temporal Trends in the Impact of COVID-19 on Uptake of BCG and Hepatitis B Vaccines

by Yan Mathias Alves, Thaís Zamboni Berra, Reginaldo Bazon Vaz Tavares, Nathalia Zini, Quézia Rosa Ferreira, Licia Kellen de Almeida Andrade, Ariela Fehr Tártaro, Maria Eduarda Pagano Pelodan, Beatriz Fornaziero Vigato, Beatriz Kuroda Silveira, Ana Luiza Brasileiro Nato Marques Assumpção, Marcela Antunes Paschoal Popolin, Patricia Abrahão Curvo, Simone Protti-Zanatta, Maria Del Pilar Serrano-Gallardo, Ricardo Alexandre Arcêncio, Pedro Fredemir Palha and Jaqueline Garcia de Almeida Ballestero

Vaccines 2024, 12(12), 1434; https://doi.org/10.3390/vaccines12121434 - 20 Dec 2024

Abstract

Introduction: Vaccines are a significant public health achievement, which are crucial for child survival and disease control globally. In Brazil, the National Immunization Program (PNI) manages vaccination schedules, including essential vaccines like BCG and Hepatitis B, administered at birth. Despite achieving over 95% [...] Read more.

Introduction: Vaccines are a significant public health achievement, which are crucial for child survival and disease control globally. In Brazil, the National Immunization Program (PNI) manages vaccination schedules, including essential vaccines like BCG and Hepatitis B, administered at birth. Despite achieving over 95% coverage for years, vaccination rates have declined since 2016, a trend exacerbated by the COVID-19 pandemic. This study aims to analyze spatial and temporal trends in BCG and Hepatitis B vaccination coverage at birth, identify areas with spatial variation in these trends, classify the identified trends, and investigate the pandemic’s impact on vaccination adherence. Methods: This is an ecological study with real-world data from Brazil, focusing on vaccination coverage from 2014 to 2023. Utilizing the Spatial Variation in Temporal Trends (SVTT) technique, the study identifies municipalities’ vaccination trends. It also employs time series analysis and Interrupted Time Series methods to evaluate the pandemic’s impact on vaccination rates, using data from the PNI and the Information System on Live Births (SINASC). Results: Between January 2014 and December 2023, Brazil administered 25,902,207 doses of the BCG vaccine to children at birth, with 3911 municipalities (70.24%) showing declining trends, particularly in Florianópolis. Similarly, 22,962,434 doses of the Hepatitis B vaccine were administered, with 3284 municipalities also experiencing declines. Conclusions: It is crucial that public health policies be reevaluated to address regional disparities in vaccination coverage, particularly in more vulnerable areas. Focused interventions, such as awareness campaigns, improved access to vaccination services, and strengthened monitoring, are fundamental to reversing this trend. Full article

(This article belongs to the Special Issue Advance Public Health Through Vaccination)

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15 pages, 282 KiB

Open AccessReview

The Herpes Zoster Patient Pathway and Gaps in Current Vaccination Guidelines in Southeast Asia: Summary of a Zoster Experts’ Network Scientific Workshop

by Gyneth Lourdes G. Bibera, Peter San Martin, Desiree A. M. van Oorschot, Afif Nurul Hidayati, Deliana Permatasari, Sasheela Sri La Sri Ponnampalavanar, Kughan Govinden, Maria Christina Filomena Batac, Joselito Javier, Terapong Tantawichien, Phatu Boonmahittisut, Trinh Minh Trang and Thanh Tuyen Dang Thi

Vaccines 2024, 12(12), 1433; https://doi.org/10.3390/vaccines12121433 - 19 Dec 2024

Abstract

The burden of herpes zoster (HZ) is recognized worldwide; however, there is seemingly limited information on incidence and vaccination practices in Southeast Asia (SEA). A scientific workshop was held by the Zoster Experts’ Network to exchange and consolidate insights on the burden of [...] Read more.

The burden of herpes zoster (HZ) is recognized worldwide; however, there is seemingly limited information on incidence and vaccination practices in Southeast Asia (SEA). A scientific workshop was held by the Zoster Experts’ Network to exchange and consolidate insights on the burden of HZ and the patient pathway in SEA. The workshop included practicing clinical experts and public health specialists/epidemiologists from Indonesia, Malaysia, the Philippines, Thailand, and Vietnam. It aimed to identify gaps in the literature, outline patient pathways, and evaluate HZ vaccine recommendations among these countries. Consensus was identified on the substantial lack of epidemiological data on HZ in SEA and the need to investigate the impact of age, immunocompromising conditions, and comorbidities on the incidence and severity of HZ in the region. However, available data in SEA did indicate a rising disease and socioeconomic burden of HZ, with concerns that current treatment strategies for HZ are suboptimal. The HZ patient pathways generated by the experts highlighted common themes and differences between the five countries. Furthermore, the experts highlighted the lack of awareness of HZ and its impact on patients’ quality of life, among patients and healthcare professionals. Evaluation of the current local HZ vaccine recommendations further showed differences in age and the inclusion of at-risk populations between countries. The workshop outcomes emphasize the need for further HZ surveillance in SEA. Efforts to align and address leakage within the patient pathway and raise awareness on the impact of HZ should be prioritized. Awareness initiatives and alignment on vaccine recommendations are also needed. Full article

25 pages, 1849 KiB

Open AccessArticle

A Trivalent Live Vaccine Elicits Cross-Species Protection Against Acute Otitis Media in a Murine Model

by Haley Echlin, Amy Iverson, Abigail McKnight and Jason W. Rosch

Vaccines 2024, 12(12), 1432; https://doi.org/10.3390/vaccines12121432 - 19 Dec 2024

Viewed by 74

Abstract

Background: Acute otitis media (AOM) is a common pediatric infection worldwide and is the primary basis for pediatric primary care visits and antibiotic prescriptions in children. Current licensed vaccines have been incompletely ineffective at reducing the global burden of AOM, underscoring a [...] Read more.

Background: Acute otitis media (AOM) is a common pediatric infection worldwide and is the primary basis for pediatric primary care visits and antibiotic prescriptions in children. Current licensed vaccines have been incompletely ineffective at reducing the global burden of AOM, underscoring a major unmet medical need. The complex etiology of AOM presents additional challenges for vaccine development, as it can stem from multiple bacterial species including Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. As such, targeting multiple pathogens simultaneously may be required to significantly impact the overall disease burden. Methods: In this study, we aim to overcome this challenge by engineering a live-attenuated vaccine platform based on an attenuated mutant of S. pneumoniae that expresses H. influenzae and M. catarrhalis surface epitopes to induce protective immunity against all three pathogens. Results: The trivalent live-attenuated vaccine conferred significant protection against all three bacterial otopathogens as measured by seroconversion and the development of AOM, with the inclusion of the additional epitopes providing unexpected synergy and enhanced protection against S. pneumoniae. Conclusions: These data demonstrate a novel mechanism of introducing non-native immunogenic antigens into a live-attenuated vaccine platform to engender protection against AOM from multiple pathogenic species. Full article

(This article belongs to the Section Attenuated/Inactivated/Live and Vectored Vaccines)

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13 pages, 478 KiB

Open AccessReview

Scoping Review of Current Costing Literature on Interventions to Reach Zero-Dose Children in Low- and Middle-Income Countries

by Ann Levin, Teemar Fisseha, Heidi W. Reynolds, Gustavo Corrêa, Tewodaj Mengistu and Nancy Vollmer

Vaccines 2024, 12(12), 1431; https://doi.org/10.3390/vaccines12121431 - 19 Dec 2024

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Abstract

Introduction: A limited number of studies focus on estimating the costs of interventions to increase childhood immunization coverage in low- and middle-income countries (LMICs). Existing reviews often compare estimated costs but lack information on the methods used. The objective of this review is [...] Read more.

Introduction: A limited number of studies focus on estimating the costs of interventions to increase childhood immunization coverage in low- and middle-income countries (LMICs). Existing reviews often compare estimated costs but lack information on the methods used. The objective of this review is to summarize the methods used in costing studies that assessed interventions to reach zero-dose (ZD) children. Methods: We conducted a review of existing studies that estimate the costs of increasing childhood vaccination and reducing prevalence of ZD children in LMICs. We conducted searches of PubMed using terms including “immunization”, “cost”, “coverage increase”, “zero-dose”, and “LMIC”, and further extended our search to bibliographies and gray literature from organizations working to reach ZD children. We only included articles that estimated the cost of interventions to increase childhood vaccination and/or reach ZD children and not articles about introducing new vaccines or other age groups. We categorized each article according to their costing methods, cost components, types of costs calculated, and presence of uncertainty analysis. Results: Eleven articles met our inclusion criteria. Interventions costs varied from USD 0.08 per additional dose for SMS reminders in Kenya to USD 67 per dose for cash transfers in Nicaragua. Most of the studies were from South Asia: India (4), Pakistan (2), and Bangladesh (1). The rest were from Africa (3) and Latin America (1). Most articles did not include a description of their costing methods. Only three described their methods in detail. Conclusions: Few studies have estimated the costs of increasing childhood vaccination coverage and reducing the number of ZD children in LMICs. The wide variation in intervention costs underscores the need for standardized costing methodologies to enhance comparability across studies. Only three studies detailed their costing methods, making comparisons challenging. Establishing research principles for costing ZD interventions could strengthen future evidence for policymaking. Full article

(This article belongs to the Special Issue 50 Years of Immunization—Steps Forward)

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8 pages, 216 KiB

Open AccessArticle

Improving Childhood Immunization Service Delivery in Cameroon: A Synthesis of Caregiver Experiences and Recommendations

by Yauba Saidu, Jessica Gu, Budzi Michael Ngenge, Sangwe Clovis Nchinjoh, Amani Adidja, Nnang Edwidge, Nkwain Muteh, Clarence Mbanga, Diaby Ousmane, Andreas Njoh, Junie Flegere, Demba Diack, Emanuele Montomoli and Sue Ann Costa Clemens

Vaccines 2024, 12(12), 1430; https://doi.org/10.3390/vaccines12121430 - 19 Dec 2024

Viewed by 241

Abstract

Background/Objectives: A “people-centered” approach is one of the core principles of the Immunization Agenda (IA) 2030 and emphasizes the need for services to be organized around the needs and expectations of individuals and the community. A better understanding of the immunization experience from [...] Read more.

Background/Objectives: A “people-centered” approach is one of the core principles of the Immunization Agenda (IA) 2030 and emphasizes the need for services to be organized around the needs and expectations of individuals and the community. A better understanding of the immunization experience from the client’s perspective is key to guiding the design of policies and interventions aimed at improving immunization delivery and coverage. This study provides a synthesis of the immunization experiences of children’s caregivers in Cameroon, highlighting potential barriers for timely and complete immunization. Methods: A descriptive cross-sectional study was conducted, targeting caregivers of children brought to selected health facilities for immunization in all ten regions of Cameroon. Using structured questionnaires, data were collected from caregivers and analyzed using STATA version 13. Results: In total, 1230 caregivers were interviewed in 265 health facilities. The median age of participants was 27 years and the median number of children per caregiver was two children. Most (87%) of the study participants reported to be satisfied with immunization service delivery. The median waiting time for vaccination was 1 h 48 min, with regional median waiting times ranging from 18 min in the South region to 4 h 6 min in the North region. About a quarter (24%) of surveyed participants reported to have presented to a health facility for immunization services and were turned away without achieving the purpose for which they came at least once. About half (48%) of the caregivers had never heard about planned vaccination activities in their communities. Conclusion: While most caregivers appeared to be satisfied with immunization service delivery in Cameroon, our study highlights some notable caregiver concerns (long waiting times, unproductive immunization visits and inadequate information about outreach activities) which, if addressed, may go a long way to enhance the immunization experience of caregivers in Cameroon, build trust in immunization services and thus improve vaccination uptake. Full article

(This article belongs to the Special Issue Navigating Public Perceptions of Vaccination: Understanding Attitudes and Challenges)

16 pages, 1731 KiB

Open AccessArticle

Multi-Antigen Elephant Endotheliotropic Herpesvirus (EEHV) mRNA Vaccine Induces Humoral and Cell-Mediated Responses in Mice

by Jessica R. Watts, Jennifer L. Spencer Clinton, Jeroen Pollet, Rongsheng Peng, Jie Tan and Paul D. Ling

Vaccines 2024, 12(12), 1429; https://doi.org/10.3390/vaccines12121429 - 18 Dec 2024

Viewed by 183

Abstract

Background/Objectives: Elephant endotheliotropic herpesvirus (EEHV) causes lethal hemorrhagic disease (HD) in Asian and African elephants in human care and the wild. It is the leading cause of death for young Asian elephants in North American and European zoos despite sensitive diagnostic tests and [...] Read more.

Background/Objectives: Elephant endotheliotropic herpesvirus (EEHV) causes lethal hemorrhagic disease (HD) in Asian and African elephants in human care and the wild. It is the leading cause of death for young Asian elephants in North American and European zoos despite sensitive diagnostic tests and improved treatments. Thus, there is a critical need to develop an effective vaccine to prevent severe illness and reduce mortality from EEHV-HD. We generated a multi-antigenic EEHV mRNA vaccine to address this need that encodes the EEHV1A-subtype glycoproteins gB, gH, gL, and gO. These conserved proteins are the entry machinery for several herpesviruses in the betaherpesvirus subfamily and elicit humoral and cellular immunity in naturally infected elephants. Methods: Outbred CD-1 mice were vaccinated with two doses of an mRNA vaccine comprising modified EEHV1A gB, gH, gL, and gO mRNAs encapsulated into lipid nanoparticles. Humoral and T-cell immunity was assessed three weeks after the first dose or three weeks after the booster dose using luciferase immunoprecipitation system assays and flow cytometry, respectively. Results: The CD-1 mice vaccinated once had detectable antibody titers against gB, gH, and gL that increased significantly three weeks after a booster dose. Activated CD4⁺ and CD8⁺ T cells secreting cytokines associated with a T_H1 response were induced against all four glycoproteins. No adverse effects were observed following one or two doses of the vaccine. Conclusions: We found that gB, gH, gL, and gO as a multivalent vaccine stimulated robust humoral and cell-mediated immunity. This is a critical step for moving this candidate EEHV1A mRNA vaccine into clinical trials in Asian elephants. Full article

(This article belongs to the Section Veterinary Vaccines)

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17 pages, 4442 KiB

Open AccessArticle

Pichia pastoris-Derived β-Glucan Capsules as a Delivery System for DNA Vaccines

by Samara Sousa de Pinho, Maria da Conceição Viana Invenção, Anna Jéssica Duarte Silva, Larissa Silva de Macêdo, Benigno Cristofer Flores Espinoza, Lígia Rosa Sales Leal, Marco Antonio Turiah Machado da Gama, Ingrid Andrêssa de Moura, Micaela Evellin dos Santos Silva, Débora Vitória Santos de Souza, Marina Linhares Lara, Julia Nayane Soares Azevedo Alves and Antonio Carlos de Freitas

Vaccines 2024, 12(12), 1428; https://doi.org/10.3390/vaccines12121428 - 18 Dec 2024

Viewed by 277

Abstract

Background/Objectives: DNA vaccines are rapidly produced and adaptable to different pathogens, but they face considerable challenges regarding stability and delivery to the cellular target. Thus, effective delivery methods are essential for the success of these vaccines. Here, we evaluated the efficacy of capsules [...] Read more.

Background/Objectives: DNA vaccines are rapidly produced and adaptable to different pathogens, but they face considerable challenges regarding stability and delivery to the cellular target. Thus, effective delivery methods are essential for the success of these vaccines. Here, we evaluated the efficacy of capsules derived from the cell wall of the yeast Pichia pastoris as a delivery system for DNA vaccines. Methods: The capsules were extracted from the yeast Pichia pastoris strain GS115, previously grown in a YPD medium. pVAX1 expression vector was adopted to evaluate the DNA vaccine insertion and delivery. Three encapsulation protocols were tested to identify the most effective in internalizing the plasmid. The presence of plasmids inside the capsules was confirmed by fluorescence microscopy, and the encapsulation efficiency was calculated by the difference between the initial concentration of DNA used for insertion and the concentration of unencapsulated DNA contained in the supernatant. The capsules were subjected to different temperatures to evaluate their thermostability and were co-cultured with macrophages for phagocytosis analysis. HEK-293T cells were adopted to assess the cytotoxicity levels by MTT assay. Results: The microscopy results indicated that the macrophages successfully phagocytosed the capsules. Among the protocols tested for encapsulation, the one with 2% polyethylenimine for internalization showed the highest efficiency, with an encapsulation rate above 80%. However, the vaccine capsules obtained with the protocol that used 5% NaCl showed better thermal stability and encapsulation efficiency above 63% without induction of cell viability loss in HEK 293T. Conclusions: We successfully described a vaccine delivery system using yeast capsules derived from Pichia pastoris, demonstrating its potential for DNA vaccine delivery for the first time. Additional studies will be needed to characterize and improve this delivery strategy. Full article

(This article belongs to the Special Issue Advance in Nanoparticles as Vaccine Adjuvants)

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14 pages, 1034 KiB

Open AccessArticle

Post-COVID-19 Vaccination and Long COVID: Insights from Patient-Reported Data

by Tom C. Quach, Mitchell G. Miglis, Lu Tian, Hector Bonilla, Phillip C. Yang, Lauren Grossman, Amogha Paleru, Vincent Xin, Anushri Tiwari, Robert W. Shafer and Linda N. Geng

Vaccines 2024, 12(12), 1427; https://doi.org/10.3390/vaccines12121427 - 18 Dec 2024

Viewed by 370

Abstract

Introduction: COVID-19 vaccinations reduce the severity and number of symptoms for acute SARS-CoV-2 infections and may reduce the risk of developing Long COVID, also known as post-acute sequelae of SARS-CoV-2 (PASC). Limited and heterogenous data exist on how these vaccinations received after COVID-19 [...] Read more.

Introduction: COVID-19 vaccinations reduce the severity and number of symptoms for acute SARS-CoV-2 infections and may reduce the risk of developing Long COVID, also known as post-acute sequelae of SARS-CoV-2 (PASC). Limited and heterogenous data exist on how these vaccinations received after COVID-19 infection might impact the symptoms and trajectory of PASC, once persistent symptoms have developed. Methods: We investigated the association of post-COVID-19 vaccination with any SARS-CoV-2 vaccine(s) on PASC symptoms in two independent cohorts: a retrospective chart review of self-reported data from patients (n = 128) with PASC seen in the Stanford PASC Clinic between May 2021 and May 2022 and a 2023 multinational survey assessment of individuals with PASC (n = 484). Findings: Within the PASC Clinic patient cohort (n = 128), 58.6% (n = 75) were female, and 41.4% (n = 53) were male; 50% (n = 64) were white, and 38.3% (n = 49) were non-white. A total of 60.2% (n = 77) of PASC Clinic patients reported no change in their PASC symptoms after vaccination, 17.2% (n = 22) reported improved symptoms, and 22.7% (n = 29) reported worsened symptoms. In the multinational survey cohort (n = 484), 380 were from the U.S., and 104 were from outside the U.S.; 88.4% (n = 428) were female, and 11.6% (n = 56) were male; and 88.8% (n = 430) were white, and 11.2% (n = 54) were non-white. The distribution of survey self-reported vaccine effects on PASC symptoms was 20.2% worsened (n = 98), 60.5% no effect (n = 293), and 19.2% improved (n = 93). In both cohorts, demographic features, including age, sex, and race/ethnicity, were not significantly associated with post-vaccination PASC symptom changes. There was also a non-significant difference in the median dates of COVID-19 infection among the different outcomes. BMI was significant for symptom improvement (p = 0.026) in the PASC Clinic cohort, while a history of booster doses was significant for symptom improvement (p < 0.001) in the survey cohort. Conclusions: Most individuals with PASC did not report significant changes in their overall PASC symptoms following COVID-19 vaccinations received after PASC onset. Further research is needed to better understand the relationship between COVID-19 vaccinations and PASC. Full article

(This article belongs to the Special Issue COVID Vaccines: Design, Development, and Immune Response Studies: 2nd Edition)

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8 pages, 447 KiB

Open AccessArticle

Immunoprophylaxis with MV140 Is Effective in the Reduction of Urinary Tract Infections—A Prospective Real-Life Study

by Filipe Abadesso Lopes, Miguel Miranda, André Ye, Joana Rodrigues, Paulo Pé-Leve, José Palma Reis and Ricardo Pereira e Silva

Vaccines 2024, 12(12), 1426; https://doi.org/10.3390/vaccines12121426 - 18 Dec 2024

Viewed by 268

Abstract

Background/Objectives: Urinary tract infections (UTI) represent a highly frequent and debilitating disease. Immunoactive prophylaxis, such as the polyvalent bacterial whole-cell-based sublingual vaccine MV140, have been developed to avoid antibiotic use. However, the effectiveness of this tool in the Portuguese population is still unknown. [...] Read more.

Background/Objectives: Urinary tract infections (UTI) represent a highly frequent and debilitating disease. Immunoactive prophylaxis, such as the polyvalent bacterial whole-cell-based sublingual vaccine MV140, have been developed to avoid antibiotic use. However, the effectiveness of this tool in the Portuguese population is still unknown. This study aims at assessing the effectiveness of treatment with MV140 in a cohort of Portuguese patients presenting with recurrent UTIs. Methods: Prospective observational real-life study of 125 patients with complicated and uncomplicated recurrent UTIs treated with MV140. The primary outcome was a reduction in frequency and severity of UTIs after a follow-up of 12 months. Overall satisfaction, adverse events, and assessment of the effectiveness of MV140 in subgroups of patients with specific risk factors for UTIs were secondary outcomes. Results: In the 12 months after treatment outset, 38% of patients were UTI-free, 34% reported 1 or 2 UTI episodes, and the remaining 28% presented 3 or more UTIs, corresponding to a mean reduction of 3.20 (2.87–3.53, 95% C.I.; p < 0.001) UTI episodes per year per patient. The effectiveness of MV140 was the same regardless of sex, BMI, regular sexual activity, hypertension, diabetes mellitus, depression, paraplegia, performance of intermittent self-catheterization, indwelling bladder catheter, or previous use of other UTI-preventing vaccines. We observed a higher effectiveness in post-menopausal women compared to pre-menopausal (74.7% vs. 59.4%, respectively, p = 0.029). A total of 73% of patients reported a reduction in symptom severity or days of disease, and the mean global satisfaction was 7.52/10. Conclusions: MV140 demonstrated to be effective in the reduction rate of recurrent UTIs in a cohort of adult Portuguese patients. Full article

(This article belongs to the Section Vaccine Efficacy and Safety)

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3 pages, 151 KiB

Open AccessEditorial

Special Issue: Challenges and Future Trends of COVID-19 Vaccination

by Imran Mirza

Vaccines 2024, 12(12), 1425; https://doi.org/10.3390/vaccines12121425 - 18 Dec 2024

Viewed by 270

Abstract

During the COVID-19 pandemic, over 13 [...] Full article

11 pages, 589 KiB

Open AccessArticle

Reaching Forest Workers with Yellow Fever Vaccine Through Engagement of the Private Sector in Central African Republic

by Gertrude Noufack, Placide Bissengue, Junior Koma Zobanga, Junior Stève Cyrille Malingao, Mory Keita, Marie Constance Razaiarimanga and Marie-Eve Raguenaud

Vaccines 2024, 12(12), 1424; https://doi.org/10.3390/vaccines12121424 - 17 Dec 2024

Viewed by 494

Abstract

Background/Objectives: Yellow fever (YF) outbreaks continue to affect populations that are not reached by routine immunization services, such as workers at a high risk of occupational exposure to YF. In the Central African Republic (CAR), YF cases were detected in districts characterized [...] Read more.

Background/Objectives: Yellow fever (YF) outbreaks continue to affect populations that are not reached by routine immunization services, such as workers at a high risk of occupational exposure to YF. In the Central African Republic (CAR), YF cases were detected in districts characterized by the presence of workers in forest areas. We developed an innovative approach based on a local partnership with private companies of the extractive industry to administer YF vaccine to workers in remote areas during the response to an outbreak. Methods: The planning stage of the campaign included the mapping of forestry and mining companies through the involvement of national and/or local representatives of companies from both the formal and informal sectors. Information sessions and mobilization targeted the heads of operating companies. Advanced and mobile strategies were used to target workers on their work site. Companies provided logistical support including transportation and communication and set up temporary vaccination posts. Results: Using this local partnership, it was possible to vaccinate over 70,000 workers (5.8% of the entire vaccinated population) in hard-to-reach areas, protecting them from YF. This represented around 47% of the estimated number of workers and dependents. The partnership with the private sector also contributed to increasing knowledge on the risk of YF and means of protection among a high-risk community. Conclusions: Private companies represent potentially useful actors that can contribute to the protection of high-risk workers and to the prevention and control YF outbreaks. The experience in the CAR has demonstrated that it is possible to obtain support from private companies, including informal ones, for a vaccination campaign. Full article

(This article belongs to the Section Vaccines against Infectious Diseases)

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20 pages, 9291 KiB

Open AccessArticle

Development Using Bioluminescence Imaging of a Recombinant Anguillid Herpesvirus 1 Vaccine Candidate Associated with Normal Replication In Vitro but Abortive Infection In Vivo

by Haiyan Zhang, Arun Sridhar, Natacha Delrez, Bo He, Sophie Fourny, Yuan Gao, Owen Donohoe and Alain F. C. Vanderplasschen

Vaccines 2024, 12(12), 1423; https://doi.org/10.3390/vaccines12121423 - 17 Dec 2024

Viewed by 428

Abstract

Background/Objectives: Anguillid herpesvirus 1 (AngHV-1) (recently renamed Cyvirus anguillidallo 1) is the etiologic agent of a lethal disease that affects several eel species. It is thought to be one of the main infectious agents causing a population decline in wild eels and economic [...] Read more.

Background/Objectives: Anguillid herpesvirus 1 (AngHV-1) (recently renamed Cyvirus anguillidallo 1) is the etiologic agent of a lethal disease that affects several eel species. It is thought to be one of the main infectious agents causing a population decline in wild eels and economic loss within the eel aquaculture sector. To date, no vaccines are available against AngHV-1. Recently, we developed a safe and efficacious live attenuated recombinant vaccine against Cyprinid herpesvirus 3 (CyHV-3). This CyHV-3 recombinant vaccine encodes a deletion of ORF57. Orthologues of CyHV-3 ORF57 exist in Cyprinid herpesvirus 2 (CyHV-2, ORF57) and AngHV-1 (ORF35). Methods: In the present study, using recombinant strains and bioluminescent in vivo imaging, we investigated the effect of AngHV-1 ORF35 deletion on virus replication in vitro, virulence in vivo, and the potential of an AngHV-1 ORF35-deleted recombinant as a vaccine candidate for the mass vaccination of eels by immersion. With this goal in mind, we produced ORF35-deleted recombinants using two parental strains: a UK strain and a recombinant derived from the former strain by insertion of a Luciferase–GFP reporter cassette into a non-coding intergenic region. Results: Analyses of ORF35-deleted recombinants led to the following observations: (i) AngHV-1 ORF35 is not essential for viral growth in cell culture, and its deletion does not affect the production of extracellular virions despite reducing the size of viral plaque. (ii) In contrast to what has been observed for CyHV-3 ORF57 and CyHV-2 ORF57, in vivo bioluminescent analyses revealed that AngHV-1 ORF35 is an essential virulence factor and that its deletion led to abortive infection in vivo. (iii) Inoculation of the AngHV-1 ORF35-deleted recombinant by immersion induced a protective immune response against a wild-type challenge. This protection was shown to be dose-dependent and to rely on the infectivity of AngHV-1 ORF35-deleted virions. Conclusions: This study suggests that the AngHV-1 ORF35 protein has singular properties compared to its orthologues encoded by CyHV-2 and CyHV-3. It also supports the potential of AngHV-1 ORF35-deleted recombinants for the mass vaccination of eels by immersion. Full article

(This article belongs to the Special Issue Animal Herpesviruses)

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Graphical abstract

19 pages, 3620 KiB

Open AccessArticle

Evaluating the Protective Role of Intranasally Administered Avian-Derived IgY Against SARS-CoV-2 in Syrian Hamster Models

by Mónika Madai, Dániel Hanna, Roland Hetényi, Fanni Földes, Zsófia Lanszki, Brigitta Zana, Balázs Somogyi, Henrietta Papp, Anett Kuczmog, Orsolya Faragó-Sipos, Csaba Nemes, Vilmos Palya, Dávid Géza Horváth, Gyula Balka, Krisztián Bányai, Xinkai Jia, Péter Balogh and Pál Bajnóczi

Vaccines 2024, 12(12), 1422; https://doi.org/10.3390/vaccines12121422 - 17 Dec 2024

Viewed by 334

Abstract

Background/Objectives: The ongoing COVID-19 pandemic has underscored the need for alternative prophylactic measures, particularly for populations for whom vaccines may not be effective or accessible. This study aims to evaluate the efficacy of intranasally administered IgY antibodies derived from hen egg yolks as [...] Read more.

Background/Objectives: The ongoing COVID-19 pandemic has underscored the need for alternative prophylactic measures, particularly for populations for whom vaccines may not be effective or accessible. This study aims to evaluate the efficacy of intranasally administered IgY antibodies derived from hen egg yolks as a protective agent against SARS-CoV-2 infection in Syrian golden hamsters, a well-established animal model for COVID-19. Methods: Hens were immunized with the spike protein of SARS-CoV-2 to generate IgY antibodies. These antibodies were extracted from the egg yolks, purified, and their neutralizing activity was tested in vitro. Syrian golden hamsters were then treated with the IgY antibodies before being challenged with SARS-CoV-2. Viral loads were quantified using droplet digital PCR (ddPCR), and lung pathology was assessed through histopathological analysis. Results: The in vitro assays showed that IgY effectively neutralized SARS-CoV-2. In the in vivo hamster model, IgY treatment led to a significant reduction in viral loads and a marked decrease in lung consolidation and inflammation compared to the positive control group. Histopathological findings further supported the protective role of IgY in reducing lung damage caused by SARS-CoV-2. Conclusions: The results demonstrate that IgY antibodies exhibit strong antiviral activity and can significantly reduce SARS-CoV-2 viral loads and associated lung pathology in hamsters. These findings suggest that IgY could be a viable prophylactic option for preventing SARS-CoV-2 infection, particularly for individuals who cannot receive or respond to vaccines. Further studies are warranted to optimize dosage and explore the long-term efficacy of IgY antibodies. Full article

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3 pages, 170 KiB

Open AccessCorrection

Correction: Kannampuzha et al. A Systematic Role of Metabolomics, Metabolic Pathways, and Chemical Metabolism in Lung Cancer. Vaccines 2023, 11, 381

by Sandra Kannampuzha, Anirban Goutam Mukherjee, Uddesh Ramesh Wanjari, Abilash Valsala Gopalakrishnan, Reshma Murali, Arunraj Namachivayam, Kaviyarasi Renu, Abhijit Dey, Balachandar Vellingiri, Harishkumar Madhyastha and Raja Ganesan

Vaccines 2024, 12(12), 1421; https://doi.org/10.3390/vaccines12121421 - 17 Dec 2024

Viewed by 163

Abstract

Following the publication of paper [...] Full article

21 pages, 4407 KiB

Open AccessArticle

Development, Pre-Clinical Safety, and Immune Profile of RENOVAC—A Dimer RBD-Based Anti-Coronavirus Subunit Vaccine

by Muzaffar Muminov, Nargiza Tsiferova, Egor Pshenichnov, Khusnora Ermatova, Oksana Charishnikova, Alisher Abdullaev, Yuliya Levitskaya, Dilbar Dalimova, Sandhya MVS, Geetanjali Tomar, Ankush Dewle, Pradhnya Choudhari, Aditi Wangikar, Amol Jadhav, Mrunal Mule, Pralhad Wangikar, Ibrokhim Abdurakhmonov and Shahlo Turdikulova

Vaccines 2024, 12(12), 1420; https://doi.org/10.3390/vaccines12121420 - 17 Dec 2024

Viewed by 633

Abstract

Background: The development of effective and safe vaccines and their timely delivery to the public play a crucial role in preventing and managing infectious diseases. Many vaccines have been produced and distributed globally to prevent COVID-19 infection. However, establishing effective vaccine development platforms [...] Read more.

Background: The development of effective and safe vaccines and their timely delivery to the public play a crucial role in preventing and managing infectious diseases. Many vaccines have been produced and distributed globally to prevent COVID-19 infection. However, establishing effective vaccine development platforms and evaluating their safety and immunogenicity remains critical to increasing health security, especially in developing countries. Objectives: Therefore, we developed a local subunit vaccine candidate, RENOVAC, and reported its toxicity and immunogenicity profile in animal models. Methods: First, the synthetic gene-coding tandem RBD linked with the GS linker was cloned into the expression vector and expressed in CHO cells. The protein was then purified and filter sterilized, and 10 µg/dose and 25 µg/dose formulations were finally examined for the 14-day repeated dose toxicity followed by the immunogenic profile in preclinical studies. Results: When administered to Sprague Dawley rats by intramuscular route, the vaccine was well tolerated up to and including the dose of 25 µg/animal, and no toxicologically adverse changes were noted. The observed change in weight of the thymus and spleen might be related to the immunological response to the vaccine. The dimer RBD vaccine demonstrated the ability to generate high levels of specific immunoglobulins (IGs) and neutralization antibodies (NAbs). Finally, changes in the amounts of specific T cells and cytokines after vaccination suggested that the vaccine mainly triggers an immune response by activating CD4+ Th2-cells, which then activate B-cells to provide humoral immunity. Conclusions: The study suggests that, based on its reliable immunogenicity and acceptable safety, the vaccine can be further directed for clinical trials. Full article

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16 pages, 782 KiB

Open AccessSystematic Review

The Dynamics of Antibody Titres Against SARS-CoV-2 in Vaccinated Healthcare Workers: A Systemic Literature Review

by Vilija Gurkšnienė, Tadas Alčauskas, Fausta Majauskaitė and Ligita Jančorienė

Vaccines 2024, 12(12), 1419; https://doi.org/10.3390/vaccines12121419 - 16 Dec 2024

Viewed by 534

Abstract

Background and Objectives: Given that COVID-19 vaccination is a relatively recent development, particularly when compared to immunisation against other diseases, it is crucial to assess its efficacy in vaccinated populations. This literature review analysed studies that monitored antibody titres against SARS-CoV-2 in healthcare [...] Read more.

Background and Objectives: Given that COVID-19 vaccination is a relatively recent development, particularly when compared to immunisation against other diseases, it is crucial to assess its efficacy in vaccinated populations. This literature review analysed studies that monitored antibody titres against SARS-CoV-2 in healthcare workers who received COVID-19 vaccines. Methods: Using the PICO (Population, Intervention, Comparators, Outcomes) model recommended in the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines we included 43 publications which analyse antibody dynamics following primary vaccination, the effects of booster doses, and the influence of factors such as COVID-19C infection, age, and sex on antibody kinetics. Results: All the studies demonstrated a strong immunogenic response to the vaccines. Re-gardless of the vaccine used, over 95% of the pre-vaccination seronegative population be-came seropositive in all studies. Depending on the sampling intervals provided by the re-searchers, antibody levels were quantitatively highest during the first three months after vaccination, but levels inevitably declined over time. The monthly decline in antibodies observed in all these studies highlighted the necessity for booster doses. Studies analysing the impact of revaccination on antibody dynamics have confirmed that revaccination is an effective tool to boost humoral immunity against SARS-CoV-2. An-tibodies appear to persist for a longer period of time after revaccination, although they are subject to similar factors influencing antibody dynamics, such as age, comorbidities, and exposure to COVID-19. In addition, heterogeneous revaccination strategies have been shown to be more effective than homogeneous revaccination. Conclusions: Our review demonstrated that antibody levels against SARS-CoV-2 inevitably decline after vaccination, leaving the question of ongoing booster strategies open. The studies reviewed provided evidence of the effectiveness of booster vaccination, despite differences in age, sex, and prior COVID-19 infection. This suggests that repeated vaccination remains a highly effective method for mitigating the continued threat posed by COVID-19. Full article

(This article belongs to the Section COVID-19 Vaccines and Vaccination)

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46 pages, 1654 KiB

Open AccessReview

mRNA Vaccines Against COVID-19 as Trailblazers for Other Human Infectious Diseases

by Rossella Brandi, Alessia Paganelli, Raffaele D’Amelio, Paolo Giuliani, Florigio Lista, Simonetta Salemi and Roberto Paganelli

Vaccines 2024, 12(12), 1418; https://doi.org/10.3390/vaccines12121418 - 16 Dec 2024

Viewed by 486

Abstract

mRNA vaccines represent a milestone in the history of vaccinology, because they are safe, very effective, quick and cost-effective to produce, easy to adapt should the antigen vary, and able to induce humoral and cellular immunity. Methods: To date, only two COVID-19 mRNA [...] Read more.

mRNA vaccines represent a milestone in the history of vaccinology, because they are safe, very effective, quick and cost-effective to produce, easy to adapt should the antigen vary, and able to induce humoral and cellular immunity. Methods: To date, only two COVID-19 mRNA and one RSV vaccines have been approved. However, several mRNA vaccines are currently under development for the prevention of human viral (influenza, human immunodeficiency virus [HIV], Epstein–Barr virus, cytomegalovirus, Zika, respiratory syncytial virus, metapneumovirus/parainfluenza 3, Chikungunya, Nipah, rabies, varicella zoster virus, and herpes simplex virus 1 and 2), bacterial (tuberculosis), and parasitic (malaria) diseases. Results: RNA viruses, such as severe acute respiratory syndrome coronavirus (SARS-CoV)-2, HIV, and influenza, are characterized by high variability, thus creating the need to rapidly adapt the vaccines to the circulating viral strain, a task that mRNA vaccines can easily accomplish; however, the speed of variability may be higher than the time needed for a vaccine to be adapted. mRNA vaccines, using lipid nanoparticles as the delivery system, may act as adjuvants, thus powerfully stimulating innate as well as adaptive immunity, both humoral, which is rapidly waning, and cell-mediated, which is highly persistent. Safety profiles were satisfactory, considering that only a slight increase in prognostically favorable anaphylactic reactions in young females and myopericarditis in young males has been observed. Conclusions: The COVID-19 pandemic determined a shift in the use of RNA: after having been used in medicine as micro-RNAs and tumor vaccines, the new era of anti-infectious mRNA vaccines has begun, which is currently in great development, to either improve already available, but unsatisfactory, vaccines or develop protective vaccines against infectious agents for which no preventative tools have been realized yet. Full article

(This article belongs to the Topic Advances in Vaccines and Antimicrobial Therapy)

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14 pages, 506 KiB

Open AccessArticle

The Safety and Immunogenicity of a 13-Valent Pneumococcal Polysaccharide Conjugate Vaccine (CRM197/TT) in Infants: A Double-Blind, Randomized, Phase III Trial

by Zhiqiang Xie, Jiangjiao Li, Xue Wang, Lili Huang, Jinbo Gou, Wei Zhang, Haitao Huang, Wangyang You, Feiyu Wang, Xiaolong Li, Jinming Zhang, Qiang Han, Xiaomin Ma and Yanxia Wang

Vaccines 2024, 12(12), 1417; https://doi.org/10.3390/vaccines12121417 - 16 Dec 2024

Viewed by 406

Abstract

Objectives: This study aimed to evaluate the immunogenicity and safety of a 13-valent pneumococcal polysaccharide conjugate vaccine (CRM197/TT) (PCV13i) in infants. Methods: A total of 1200 infants were randomly assigned to either the experimental PCV13i group or the control PCV13 group in a [...] Read more.

Objectives: This study aimed to evaluate the immunogenicity and safety of a 13-valent pneumococcal polysaccharide conjugate vaccine (CRM197/TT) (PCV13i) in infants. Methods: A total of 1200 infants were randomly assigned to either the experimental PCV13i group or the control PCV13 group in a 1:1 ratio. Each group received a three-dose series of the vaccine at 2, 4, and 6 months of age, followed by a booster dose at 12–15 months. Blood samples were collected before and 30 days after both primary and booster vaccinations. The primary immunogenicity endpoints were the seropositive rate and the geometric mean concentration (GMC) of IgG antibodies against the 13 pneumococcal serotypes. The primary safety endpoint was the incidence of adverse reactions within 0–7 days and 0–30 days after vaccination. Results: Results showed that the experimental PCV13i was well tolerated, with a safety profile comparable to that of the control vaccine. Following primary vaccination, the GMCs of IgG responses against serotypes 1, 5, 6A, 6B, 14, and 18C in the experimental group were lower than those in the control group, while responses against serotypes 3, 4, 7F, 9V, 19A, 19F, and 23F were higher. The experimental group exhibited higher opsonophagocytic killing assay (OPA) geometric mean titers (GMTs) for serotypes 3, 7F, 19A, and 19F compared to the control group, while GMTs for serotypes 1, 5, 6A, and 18C were lower. Following booster vaccination, OPA GMTs of the experimental group remained higher than those of the control group for serotypes 3, 7F, and 19F, while GMTs for serotype 5 were lower. Both vaccines induced robust immune responses, with high seropositive rates and significant increases in antibody levels following vaccination. Conclusions: The experimental PCV13i demonstrated non-inferiority to the control PCV13 in terms of immunogenicity. Full article

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12 pages, 1811 KiB

Open AccessArticle

The Impact of Genetic Variation on Duck Hepatitis A Virus (DHAV) Vaccine Efficacy: A Comparative Study of DHAV-1 and DHAV-3 Against Emerging Variant Strains

by Sang-Won Kim, Cheng-Dong Yu, Jong-Yeol Park, Xiu-Li Ma, Tong Zhu, Yu-Feng Li, Se-Yeoun Cha, Hyung-Kwan Jang, Min Kang and Bai Wei

Vaccines 2024, 12(12), 1416; https://doi.org/10.3390/vaccines12121416 - 16 Dec 2024

Viewed by 487

Abstract

Background/Objective: Duck virus hepatitis (DVH), caused by duck hepatitis A virus (DHAV), poses significant challenges to duck farming due to high mortality rates in young ducklings. Despite the widespread use of live attenuated vaccines, the genetic diversity within DHAV strains has diminished their [...] Read more.

Background/Objective: Duck virus hepatitis (DVH), caused by duck hepatitis A virus (DHAV), poses significant challenges to duck farming due to high mortality rates in young ducklings. Despite the widespread use of live attenuated vaccines, the genetic diversity within DHAV strains has diminished their cross-protection efficacy. This study aimed to evaluate the cross-protective efficacy of current DHAV-1 and DHAV-3 vaccines against genetically divergent wild strains. Methods: Phylogenetic analyses of the VP1 genes from DHAV-1 and DHAV-3 were conducted. Both DHAV-1 and DHAV-3 vaccines were tested in ducklings, with and without maternal-derived antibodies (MDA), through challenge trials with homologous and heterologous strains. Results: In the phylogenetic analysis, compared to vaccine strains, DHAV-1 and DHAV-3 field variant strains were classified into different genotypes. In ducklings without MDA, the DHAV-1 vaccine provided 60% survival against homologous strains by 2 days post-vaccination (DPV) and complete protection by 4 DPV, while survival rates against heterologous strains ranged from 40 to 60%. In ducklings with MDA, the DHAV-1 vaccine provided full protection with an additional vaccination for day-old ducklings against heterologous strains. The DHAV-3 vaccine conferred complete protection against both homologous and heterologous strains by 2 DPV, regardless of MDA presence. Conclusions: The DHAV-3 vaccine demonstrated robust cross-protection across genotypes, while the DHAV-1 vaccine showed limitations against genetically divergent strains. These findings highlight the necessity for genotype-matched vaccines and optimized immunization strategies to enhance protection against evolving DHAV field strains. Full article

(This article belongs to the Section Veterinary Vaccines)

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16 pages, 722 KiB

Open AccessReview

Seasonal Influenza Vaccination Programs in the Americas: A Platform for Sustainable Life-Course Immunization and Its Role for Pandemic Preparedness and Response

by Francisco Nogareda, Margherita Ghiselli, Martha Velandia-González, Bremen de Mucio, Jorge Jara, Paula Couto, Angel Rodriguez, Marc Rondy, Andrea Vicari, Murat Hakan Ozturk, Shoshanna Goldin, Alba Vilajeliu, Eva Leidman, Jaymin Patel, Julie Carlton, Ashley L. Fowlkes, Eduardo Azziz-Baumgartner, Daniel Salas Peraza and Alba Maria Ropero

Vaccines 2024, 12(12), 1415; https://doi.org/10.3390/vaccines12121415 - 16 Dec 2024

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Abstract

Background: Vaccination is one of the most effective measures to prevent influenza illness and its complications. Since the 1980s, countries and territories in the Americas have progressively implemented influenza vaccination operations in high-risk priority groups—such as older adults, pregnant persons, persons with comorbidities [...] Read more.

Background: Vaccination is one of the most effective measures to prevent influenza illness and its complications. Since the 1980s, countries and territories in the Americas have progressively implemented influenza vaccination operations in high-risk priority groups—such as older adults, pregnant persons, persons with comorbidities and health workers. Methods: In this review, we present the history and progress of the seasonal influenza program in the Americas, how the program contributed to the efficient and timely roll-out of the COVID-19 vaccines during the pandemic, and how the program can be used to promote immunization operations across the life span for existing and future vaccines. Results: The influenza A(H1N1)pdm09 pandemic in 2009 and the COVID-19 pandemic in 2020–2023 underscored the importance of having a robust seasonal influenza vaccination program for pandemic preparedness and response. Overall, countries with existing seasonal influenza vaccination programs were better prepared and rolled out the delivery of COVID-19 vaccines more quickly and effectively compared to other countries where the influenza vaccination platform was weak or non-existent. Conclusions: Traditionally, national immunization programs of developing countries have been predominately focused on newborns, children younger than five years and school-aged children while often limiting their investment in effective adult vaccination programs; these programs are typically isolated to high-income countries. Countries in Latin America have been the exception, with strong influenza vaccination programs for adults regardless of national income level. The presence of functional and effective adult influenza vaccination programs can also facilitate the acceptance and uptake of other adult vaccines targeting priority groups at higher risk for severe illness or complications. Full article

(This article belongs to the Special Issue 50 Years of Immunization—Steps Forward)

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Open AccessArticle

Stakeholder Consultation Workshop on the Perceived Value of Thermostable Vaccines to Relieve Program Barriers: A Case Study from Côte d’Ivoire

by Anna-Lea Kahn, Dijana Spasenoska, Kouadio Daniel Ekra, Soplé Ruth Coulibaly, Kossia Yao, Sié Kabran Kouadio, Aminatou Sar and Joanie Robertson

Vaccines 2024, 12(12), 1414; https://doi.org/10.3390/vaccines12121414 - 16 Dec 2024

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Abstract

Background: Persistent inequities in access to vaccinations pose challenges for immunization programs worldwide. Innovations facilitating vaccine delivery, such as leveraging vaccine thermostability through a Controlled Temperature Chain (CTC), have emerged as a potential solution to increase coverage in low- and middle-income countries (LMICs) [...] Read more.

Background: Persistent inequities in access to vaccinations pose challenges for immunization programs worldwide. Innovations facilitating vaccine delivery, such as leveraging vaccine thermostability through a Controlled Temperature Chain (CTC), have emerged as a potential solution to increase coverage in low- and middle-income countries (LMICs) countries such as Côte d’Ivoire, reducing dependence on the cold chain and improving vaccine delivery efficiency. However, the added value of thermostable vaccines and their integration into national immunization programs is under-recognized by stakeholders. This consultation aimed to convene key immunization stakeholders in Côte d’Ivoire in order to examine their perceptions regarding the value of vaccine thermostability to address barriers to outreach and equity in immunization programs. Methods: A novel workshop model involving structured group discussions was used to document the viewpoints of national stakeholders representing different areas of the immunization program. They prioritized barriers undermining coverage and equity in their country and explored the potential impact of CTC on the immunization program in the context of thermostable vaccines. The vaccines discussed were for Hepatitis B, Human Papillomavirus, and Meningitis. Results: The workshop outcomes highlighted the context and vaccine-specific variation of the importance of certain barriers, emphasizing the need for tailored strategies. The barriers considered most likely to be alleviated by vaccine thermostability were under the categories of human resource management, vaccine supply and logistics, and services delivery. The least relevant category of barriers concerned demand generation. Conclusions: The consultation provided valuable insights into stakeholder perspectives, priorities, and conditions for the effective integration of thermostable vaccines, informing future product development and policy decisions to optimize vaccine delivery and address immunization challenges in LMICs. Full article

(This article belongs to the Special Issue Estimating Vaccines' Value and Impact)

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Vaccines, Volume 12, Issue 12 (December 2024) – 145 articles

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