Vaccines

Research

13 pages, 2508 KiB

Open AccessArticle

Assessment of Immune Responses to a Trivalent Pichinde Virus-Vectored Vaccine Expressing Hemagglutinin Genes from Three Co-Circulating Influenza A Virus Subtypes in Pigs

by Sushmita Kumari, Jayeshbhai Chaudhari, Qinfeng Huang, Phillip Gauger, Marcelo Nunes De Almeida, Hinh Ly, Yuying Liang and Hiep L. X. Vu

Vaccines 2023, 11(12), 1806; https://doi.org/10.3390/vaccines11121806 - 2 Dec 2023

Cited by 2 | Viewed by 1537

Abstract

Pichinde virus (PICV) can infect several animal species and has been developed as a safe and effective vaccine vector. Our previous study showed that pigs vaccinated with a recombinant PICV-vectored vaccine expressing the hemagglutinin (HA) gene of an H3N2 influenza A virus of [...] Read more.

Pichinde virus (PICV) can infect several animal species and has been developed as a safe and effective vaccine vector. Our previous study showed that pigs vaccinated with a recombinant PICV-vectored vaccine expressing the hemagglutinin (HA) gene of an H3N2 influenza A virus of swine (IAV-S) developed virus-neutralizing antibodies and were protected against infection by the homologous H3N2 strain. The objective of the current study was to evaluate the immunogenicity and protective efficacy of a trivalent PICV-vectored vaccine expressing HA antigens from the three co-circulating IAV-S subtypes: H1N1, H1N2, and H3N2. Pigs immunized with the trivalent PICV vaccine developed virus-neutralizing (VN) and hemagglutination inhibition (HI) antibodies against all three matching IAV-S. Following challenge infection with the H1N1 strain, five of the six pigs vaccinated with the trivalent vaccine had no evidence of IAV-S RNA genomes in nasal swabs and bronchoalveolar lavage fluid, while all non-vaccinated control pigs showed high number of copies of IAV-S genomic RNA in these two types of samples. Overall, our results demonstrate that the trivalent PICV-vectored vaccine elicits antibody responses against the three targeted IAV-S strains and provides protection against homologous virus challenges in pigs. Therefore, PICV exhibits the potential to be explored as a viral vector for delivering multiple vaccine antigens in swine. Full article

(This article belongs to the Special Issue Vaccines against Influenza Virus)

► Show Figures

Figure 1

15 pages, 4774 KiB

Open AccessArticle

Generation of a DSF-Guided Refolded Bacterially Expressed Hemagglutinin Ectodomain of Influenza Virus A/Puerto Rico/8/1934 H1N1 as a Model for Influenza Vaccine Antigens

by Vlad-Constantin Tofan, Andreea-Laura Ermeneanu, Iuliana Caraș, Alina Lenghel, Irina-Elena Ionescu, Cătălin Țucureanu, Claudiu Gal, Crina-Georgeta Stăvaru and Adrian Onu

Vaccines 2023, 11(10), 1520; https://doi.org/10.3390/vaccines11101520 - 24 Sep 2023

Cited by 1 | Viewed by 1814

Abstract

Influenza virus infections represent an ongoing public health threat as well as an economic burden. Although seasonal influenza vaccines have been available for some decades, efforts are being made to generate new efficient, flexible, and cost-effective technologies to be transferred into production. Our [...] Read more.

Influenza virus infections represent an ongoing public health threat as well as an economic burden. Although seasonal influenza vaccines have been available for some decades, efforts are being made to generate new efficient, flexible, and cost-effective technologies to be transferred into production. Our work describes the development of a model influenza hemagglutinin antigen that is capable of inducing protection against viral challenge in mice. High amounts of the H1 hemagglutinin ectodomain, HA_18–528, were expressed in a bacterial system as insoluble inclusion bodies. Solubilization was followed by a thorough differential scanning fluorimetry (DSF)-guided optimization of refolding, which allows for fast and reliable screening of several refolding conditions, yielding tens of milligrams/L of folded protein. Structural and functional analysis revealed native-like folding as well as the presence of a mix of monomers and oligomers in solution. Mice immunized with HA_18–528 were protected when exposed to influenza A virus as opposed to mice that received full-length denatured protein. Sera of mice immunized with HA_18–528 showed both high titers of antigen-specific IgG1 and IgG2a isotypes as well as viral neutralization activity. These results prove the feasibility of the recombinant bacterial expression system coupled with DSF-guided refolding in providing influenza hemagglutinin for vaccine development. Full article

(This article belongs to the Special Issue Vaccines against Influenza Virus)

► Show Figures

Figure 1

15 pages, 663 KiB

Open AccessArticle

The Impact of the COVID-19 Pandemic on Influenza Vaccination Attitudes and Actions in Spain’s Adult Population

by Camino Prada-García, Marina Toquero-Asensio, Virginia Fernández-Espinilla, Cristina Hernán-García, Iván Sanz-Muñoz, María Dolores Calvo-Nieves, Jose M. Eiros and Javier Castrodeza-Sanz

Vaccines 2023, 11(10), 1514; https://doi.org/10.3390/vaccines11101514 - 23 Sep 2023

Cited by 6 | Viewed by 1819

Abstract

Seasonal influenza is an acute respiratory infection caused by the influenza virus which constitutes a significant public health issue associated with high morbidity and mortality. The aim of this study was to investigate changes in attitudes, perceptions, and practices regarding influenza vaccination in [...] Read more.

Seasonal influenza is an acute respiratory infection caused by the influenza virus which constitutes a significant public health issue associated with high morbidity and mortality. The aim of this study was to investigate changes in attitudes, perceptions, and practices regarding influenza vaccination in the Spanish adult population during the COVID-19 pandemic, as well as their vaccination intentions, with special attention paid to those over 65 years old and in high-risk groups. To this end, a cross-sectional study was conducted through 2219 telephone interviews, and the results were compared with results obtained a year earlier. Regarding the reasons for deciding to get vaccinated in the 2022/23 season, a significant increase was observed in vaccine confidence (36.7% vs. 42.8%), social responsibility (32.5% vs. 43.8%), and in awareness of the importance of vaccination due to COVID-19 (21.7% vs. 25.4%). Advanced age (OR 2.8, 95% CI 2.0–3.9), belonging to high-risk groups (OR 2.7, 95% CI 2.0–3.7), and prior vaccination (OR 25.3, 95% CI 19.5–32.7) emerged as significant predictors for the intent to receive the influenza vaccine in the 2022/23 season. Continuously observing shifts in perceptions and behaviors related to influenza immunization is crucial to pinpoint factors that may influence the willingness to receive the vaccine and, in this way, design public health strategies that achieve a greater acceptance of it. Full article

(This article belongs to the Special Issue Vaccines against Influenza Virus)

► Show Figures

Figure 1

15 pages, 3546 KiB

Open AccessArticle

Quadrivalent Formulation of Intranasal Influenza Vaccine M2SR (M2-Deficient Single Replication) Protects against Drifted Influenza A and B Virus Challenge

by Lindsay Hill-Batorski, Yasuko Hatta, Michael J. Moser, Sally Sarawar, Gabriele Neumann, Yoshihiro Kawaoka and Pamuk Bilsel

Vaccines 2023, 11(4), 798; https://doi.org/10.3390/vaccines11040798 - 4 Apr 2023

Cited by 2 | Viewed by 2140

Abstract

Current influenza vaccines demonstrate low vaccine efficacy, especially when the predominantly circulating strain and vaccine are mismatched. The novel influenza vaccine platform M2- or BM2-deficient single replication (M2SR and BM2SR) has been shown to safely induce strong systemic and mucosal antibody responses and [...] Read more.

Current influenza vaccines demonstrate low vaccine efficacy, especially when the predominantly circulating strain and vaccine are mismatched. The novel influenza vaccine platform M2- or BM2-deficient single replication (M2SR and BM2SR) has been shown to safely induce strong systemic and mucosal antibody responses and provide protection against significantly drifted influenza strains. In this study, we demonstrate that both monovalent and quadrivalent (Quad) formulations of M2SR are non-pathogenic in mouse and ferret models, eliciting robust neutralizing and non-neutralizing serum antibody responses to all strains within the formulation. Following challenge with wildtype influenza strains, vaccinated mice and ferrets demonstrated reduced weight loss, decreased viral replication in the upper and lower airways, and enhanced survival as compared to mock control groups. Mice vaccinated with H1N1 M2SR were completely protected from heterosubtypic H3N2 challenge, and BM2SR vaccines provided sterilizing immunity to mice challenged with a cross-lineage influenza B virus. Heterosubtypic cross-protection was also seen in the ferret model, with M2SR vaccinated animals exhibiting decreased viral titers in nasal washes and lungs following the challenge. BM2SR-vaccinated ferrets elicited robust neutralizing antibodies toward significantly drifted past and future influenza B strains. Mice and ferrets that received quadrivalent M2SR were able to mount immune responses equivalent to those seen with each of the four monovalent vaccines, demonstrating the absence of strain interference in the commercially relevant quadrivalent formulation. Full article

(This article belongs to the Special Issue Vaccines against Influenza Virus)

► Show Figures

Figure 1

11 pages, 1602 KiB

Open AccessArticle

Protection of SPF Chickens by H9N2 Y439 and G1 Lineage Vaccine against Homologous and Heterologous Viruses

by Hyun-Kyu Cho, Yong-Myung Kang, Mingeun Sagong, Juhun Kim, Hyunjun Kim, Sungjun An, Youn-Jeong Lee and Hyun-Mi Kang

Vaccines 2023, 11(3), 538; https://doi.org/10.3390/vaccines11030538 - 24 Feb 2023

Viewed by 2505

Abstract

Prior to the identification of low pathogenic avian influenza H9N2 viruses belonging to the Y280 lineage in 2020, Y439 lineage viruses had been circulating in the Republic of Korea since 1996. Here, we developed a whole inactivated vaccine (vac564) by multiple passage of [...] Read more.

Prior to the identification of low pathogenic avian influenza H9N2 viruses belonging to the Y280 lineage in 2020, Y439 lineage viruses had been circulating in the Republic of Korea since 1996. Here, we developed a whole inactivated vaccine (vac564) by multiple passage of Y439 lineage viruses and then evaluated immunogenicity and protective efficacy in specific-pathogen-free chickens. We found that LBM564 could be produced at high yield in eggs (10^8.4EID₅₀/0.1 mL; 1024 hemagglutinin units) and was immunogenic (8.0 ± 1.2 log₂) in chickens. The vaccine showed 100% inhibition of virus in the cecal tonsil with no viral shedding detected in either oropharyngeal or cloacal swabs after challenge with homologous virus. However, it did not induce effective protection against challenge with heterologous virus. An imported commercial G1 lineage vaccine inhibited viral replication against Y280 and Y439 lineage viruses in major tissues, although viral shedding in oropharyngeal and cloacal swabs was observed up until 5 dpi after exposure to both challenge viruses. These results suggest that a single vaccination with vac564 could elicit immune responses, showing it to be capable of protecting chickens against the Y439 lineage virus. Thus, our results suggest the need to prepare suitable vaccines for use against newly emerging and re-emerging H9N2 viruses. Full article

(This article belongs to the Special Issue Vaccines against Influenza Virus)

► Show Figures

Figure 1

15 pages, 967 KiB

Open AccessArticle

Knowledge, Attitude, Practice and Barriers Associated with Influenza Vaccination among Health Care Professionals Working at Tertiary Care Hospitals in Lahore, Pakistan: A Multicenter Analytical Cross-Sectional Study

by Gulshan Umbreen, Abdul Rehman, Muhammad Avais, Chanda Jabeen, Shakera Sadiq, Rubab Maqsood, Hamad Bin Rashid, Saira Afzal, Richard J. Webby and Mamoona Chaudhry

Vaccines 2023, 11(1), 136; https://doi.org/10.3390/vaccines11010136 - 6 Jan 2023

Cited by 3 | Viewed by 2790

Abstract

Health Care Professionals (HCPs), including doctors, nurses, pharmacists, and paramedics, are a high-risk group for influenza infection due to their continuous exposure to patients having a known or unknown history of influenza-like illnesses. Influenza vaccination is the most effective method of primary prevention. [...] Read more.

Health Care Professionals (HCPs), including doctors, nurses, pharmacists, and paramedics, are a high-risk group for influenza infection due to their continuous exposure to patients having a known or unknown history of influenza-like illnesses. Influenza vaccination is the most effective method of primary prevention. This study was conducted to assess knowledge, attitude, practice, and barriers associated with influenza vaccination among HCPs at tertiary care hospitals in Lahore, Pakistan. A multicenter analytical cross-sectional study was conducted among HCPs. Data were collected using a structured questionnaire. All statistical analyses were conducted in R software. A total of 400 HCPs were enrolled, and among these, 67% had a high level of knowledge and 65.5% had a positive attitude towards influenza vaccination. About 51% of HCPs adopted good practices leading to influenza vaccination. Results identified major barriers for influenza vaccinations, including unfamiliarity with vaccine availability (RII = 0.760), insufficient staff for administering the vaccine (RII = 0.649), lack of proper storage (RII = 0.625), safety concerns (RII = 0.613), and cost of vaccine (RII = 0.602). More than half of the HCPs showed a high level of knowledge, a positive attitude, and good practice against influenza vaccination. Despite the positive Knowledge, Attitude, and Practice (KAP) scores and published guidelines, a very low percentage of HCPs were vaccinated against influenza. Many hindering factors were associated with influenza vaccination. Full article

(This article belongs to the Special Issue Vaccines against Influenza Virus)

► Show Figures

Figure 1

11 pages, 494 KiB

Open AccessArticle

Safety and Viral Shedding of Live Attenuated Influenza Vaccine (LAIV) in Chinese Healthy Juveniles and Adults: A Phase Ⅰ Randomized, Double-Blind, Placebo-Controlled Study

by Li Li, Nianmin Shi, Na Xu, Haibin Wang, Hui Zhao, Haidong Xu, Dawei Liu, Zheng Zhang, Shuping Li, Junnan Zhang, Chunhui Guo, Jinglei Huo, Menghan Zhao, Fengji Luo, Liqing Yang, Yunhua Bai, Qiang Lu, Yusong Zhang, Yi Zhong and Wenhui Gao

Vaccines 2022, 10(11), 1796; https://doi.org/10.3390/vaccines10111796 - 26 Oct 2022

Cited by 1 | Viewed by 2053

Abstract

This study was a randomized, double-blind, placebo-controlled study to evaluate the safety and viral shedding of live attenuated influenza vaccine (LAIV) in Chinese healthy juveniles and adults. A total of 80 Eligible volunteers were divided into two age groups (≥18 and 3–17 years [...] Read more.

This study was a randomized, double-blind, placebo-controlled study to evaluate the safety and viral shedding of live attenuated influenza vaccine (LAIV) in Chinese healthy juveniles and adults. A total of 80 Eligible volunteers were divided into two age groups (≥18 and 3–17 years old). Volunteers were randomly and equally assigned to the experimental group and placebo-controlled group by ratio of 3:1 in each age group. Vaccination was carried out in steps. Totally, 34 (56.67%) adverse events and 24 (40.00%) adverse reactions of the LAIV group were reported. Most adverse reactions were grade 1 and grade 2, and the incidence of adverse reactions that grade 3 was 5%. The most common local reaction was runny nose/nasal congestion (n = 4, 6.67%). And the most common general reaction was fever (n = 10, 16.67%). There were no statistically significant differences in the incidence of total adverse reactions, different grades of adverse reactions, and symptoms between the experimental group and placebo-controlled group. No severe adverse events were reported. Three subjects (5.00%) had been detected vaccine strains on the 3rd day after LAIV vaccination; one was type B and the other two were H3N2. Four subjects (6.67%) had been detected with vaccine strains on the 7th day after LAIV vaccination, all were H3N2. There were no subjects detected carrying the influenza virus on the 15th day after vaccination. There were no statistically significant differences in the positive rate of vaccine strains of influenza virus between the experimental group and placebo-controlled group. The vaccine was well tolerated and not associated with increased rates in adverse reactions or the occurrence of severe adverse events. Pathogenicity of shed vaccine virus to surrounding people was not observed. Thus, Phase Ⅱ study can be carried out as scheduled. Full article

(This article belongs to the Special Issue Vaccines against Influenza Virus)

► Show Figures

Figure 1

13 pages, 982 KiB

Open AccessArticle

Membrane Chromatography-Based Downstream Processing for Cell-Culture Produced Influenza Vaccines

by Zeyu Yang, Xingge Xu, Cristina A. T. Silva, Omar Farnos, Alina Venereo-Sanchez, Cécile Toussaint, Shantoshini Dash, Irene González-Domínguez, Alice Bernier, Olivier Henry and Amine Kamen

Vaccines 2022, 10(8), 1310; https://doi.org/10.3390/vaccines10081310 - 13 Aug 2022

Cited by 7 | Viewed by 3115

Abstract

New influenza strains are constantly emerging, causing seasonal epidemics and raising concerns to the risk of a new global pandemic. Since vaccination is an effective method to prevent the spread of the disease and reduce its severity, the development of robust bioprocesses for [...] Read more.

New influenza strains are constantly emerging, causing seasonal epidemics and raising concerns to the risk of a new global pandemic. Since vaccination is an effective method to prevent the spread of the disease and reduce its severity, the development of robust bioprocesses for producing pandemic influenza vaccines is exceptionally important. Herein, a membrane chromatography-based downstream processing platform with a demonstrated industrial application potential was established. Cell culture-derived influenza virus H1N1/A/PR/8/34 was harvested from benchtop bioreactor cultures. For the clarification of the cell culture broth, a depth filtration was selected as an alternative to centrifugation. After inactivation, an anion exchange chromatography membrane was used for viral capture and further processing. Additionally, two pandemic influenza virus strains, the H7N9 subtype of the A/Anhui/1/2013 and H3N2/A/Hong Kong/8/64, were successfully processed through similar downstream process steps establishing optimized process parameters. Overall, 41.3–62.5% viral recovery was achieved, with the removal of 86.3–96.5% host cell DNA and 95.5–99.7% of proteins. The proposed membrane chromatography purification is a scalable and generic method for the processing of different influenza strains and is a promising alternative to the current industrial purification of influenza vaccines based on ultracentrifugation methodologies. Full article

(This article belongs to the Special Issue Vaccines against Influenza Virus)

► Show Figures

Figure 1

13 pages, 2132 KiB

Open AccessArticle

Vaccination with Deglycosylated Modified Hemagglutinin Broadly Protects against Influenza Virus Infection in Mice and Ferrets

by Limin Zhang, Junyu Chen, Chenguang Shen, Guosong Wang, Zhen Lu, Dian Zeng, Ying Gao, Huiqing Chen, Ningshao Xia and Yixin Chen

Vaccines 2022, 10(8), 1304; https://doi.org/10.3390/vaccines10081304 - 11 Aug 2022

Cited by 6 | Viewed by 2794

Abstract

Recent efforts have been directed toward the development of universal influenza vaccines inducing broadly neutralizing antibodies to conserved antigenic supersites of Hemagglutinin (HA). Although several studies raise the importance of glycosylation in HA antigen design, whether this theory can be widely confirmed remains [...] Read more.

Recent efforts have been directed toward the development of universal influenza vaccines inducing broadly neutralizing antibodies to conserved antigenic supersites of Hemagglutinin (HA). Although several studies raise the importance of glycosylation in HA antigen design, whether this theory can be widely confirmed remains unclear; which influenza HA with an altered glycosylation profile could impact the amplitude and focus of the host immune response. Here, we evaluated the characteristics and efficacy of deglycosylated modified HA proteins, including monoglycosylated HA (HA_mg), unglycosylated HA (HA_ug), and fully glycosylated HA (HA_fg), without treatment with H3N2 Wisconsin/67/2005. Our results showed that HA_ug could induce a cross-strain protective immune response in mice against both H3N2 and H7N9 subtypes with better antibody-dependent cellular cytotoxicity (ADCC) than the HA_mg- and HA_fg-immunized groups, which suggested that highly conserved epitopes that were masked by surface glycosylation may be exposed and thus promote the induction of broad antibodies that recognize the hidden epitopes. This strategy may also supplement the direction of deglycosylated modified HA for universal influenza vaccines. Full article

(This article belongs to the Special Issue Vaccines against Influenza Virus)

► Show Figures

Figure 1

Review

Jump to: Research, Other

29 pages, 1373 KiB

Open AccessReview

Nucleoprotein as a Promising Antigen for Broadly Protective Influenza Vaccines

by Alexandra Rak, Irina Isakova-Sivak and Larisa Rudenko

Vaccines 2023, 11(12), 1747; https://doi.org/10.3390/vaccines11121747 - 23 Nov 2023

Cited by 10 | Viewed by 2711

Abstract

Annual vaccination is considered as the main preventive strategy against seasonal influenza. Due to the highly variable nature of major viral antigens, such as hemagglutinin (HA) and neuraminidase (NA), influenza vaccine strains should be regularly updated to antigenically match the circulating viruses. The [...] Read more.

Annual vaccination is considered as the main preventive strategy against seasonal influenza. Due to the highly variable nature of major viral antigens, such as hemagglutinin (HA) and neuraminidase (NA), influenza vaccine strains should be regularly updated to antigenically match the circulating viruses. The influenza virus nucleoprotein (NP) is much more conserved than HA and NA, and thus seems to be a promising target for the design of improved influenza vaccines with broad cross-reactivity against antigenically diverse influenza viruses. Traditional subunit or recombinant protein influenza vaccines do not contain the NP antigen, whereas live-attenuated influenza vaccines (LAIVs) express the viral NP within infected cells, thus inducing strong NP-specific antibodies and T-cell responses. Many strategies have been explored to design broadly protective NP-based vaccines, mostly targeted at the T-cell mode of immunity. Although the NP is highly conserved, it still undergoes slow evolutionary changes due to selective immune pressure, meaning that the particular NP antigen selected for vaccine design may have a significant impact on the overall immunogenicity and efficacy of the vaccine candidate. In this review, we summarize existing data on the conservation of the influenza A viral nucleoprotein and review the results of preclinical and clinical trials of NP-targeting influenza vaccine prototypes, focusing on the ability of NP-specific immune responses to protect against diverse influenza viruses. Full article

(This article belongs to the Special Issue Vaccines against Influenza Virus)

► Show Figures

Figure 1

18 pages, 319 KiB

Open AccessReview

Novel Influenza Vaccines: From Research and Development (R&D) Challenges to Regulatory Responses

by Xiangchuan He, Tianxiang Zhang, Shitong Huan and Yue Yang

Vaccines 2023, 11(10), 1573; https://doi.org/10.3390/vaccines11101573 - 9 Oct 2023

Cited by 4 | Viewed by 3162

Abstract

Influenza vaccines faced significant challenges in achieving sufficient protective efficacy and production efficiency in the past. In recent decades, novel influenza vaccines, characterized by efficient and scalable production, advanced platforms, and new adjuvant technologies, have overcome some of these weaknesses and have been [...] Read more.

Influenza vaccines faced significant challenges in achieving sufficient protective efficacy and production efficiency in the past. In recent decades, novel influenza vaccines, characterized by efficient and scalable production, advanced platforms, and new adjuvant technologies, have overcome some of these weaknesses and have been widely licensed. Furthermore, researchers are actively pursuing the development of next-generation and universal influenza vaccines to provide comprehensive protection against potential pandemic subtypes or strains. However, new challenges have emerged as these novel vaccines undergo evaluation and authorization. In this review, we primarily outline the critical challenges and advancements in research and development (R&D) and highlight the improvements in regulatory responses for influenza vaccines. Full article

(This article belongs to the Special Issue Vaccines against Influenza Virus)

16 pages, 1191 KiB

Open AccessReview

The Epidemiology of Influenza and the Associated Vaccines Development in China: A Review

by Jiayou Zhang, Xuanxuan Nian, Xuedan Li, Shihe Huang, Kai Duan, Xinguo Li and Xiaoming Yang

Vaccines 2022, 10(11), 1873; https://doi.org/10.3390/vaccines10111873 - 6 Nov 2022

Cited by 8 | Viewed by 2590

Abstract

Influenza prevention and control has been one of the biggest challenges encountered in the public health domain. The vaccination against influenza plays a pivotal role in the prevention of influenza, particularly for the elderly and small children. According to the epidemiology of influenza [...] Read more.

Influenza prevention and control has been one of the biggest challenges encountered in the public health domain. The vaccination against influenza plays a pivotal role in the prevention of influenza, particularly for the elderly and small children. According to the epidemiology of influenza in China, the nation is under a heavy burden of this disease. Therefore, as a contribution to the prevention and control of influenza in China through the provision of relevant information, the present report discusses the production and batch issuance of the influenza vaccine, analysis of the vaccination status and vaccination rate of the influenza vaccine, and the development trend of the influenza vaccine in China. Full article

(This article belongs to the Special Issue Vaccines against Influenza Virus)

► Show Figures

Figure 1

Other

Jump to: Research, Review

13 pages, 787 KiB

Open AccessSystematic Review

Factors Influencing Childhood Influenza Vaccination: A Systematic Review

by Kaiyi Han, Zhiyuan Hou, Shiyi Tu, Mengyun Liu, Tracey Chantler and Heidi Larson

Vaccines 2024, 12(3), 233; https://doi.org/10.3390/vaccines12030233 - 23 Feb 2024

Cited by 2 | Viewed by 2142

Abstract

Childhood influenza vaccination coverage remains low in lower/middle-income countries. This systematic review aims to identify influencing factors around childhood influenza vaccination. A systematic literature review was conducted and included empirical studies with original data that investigated factors influencing childhood influenza vaccination. We searched [...] Read more.

Childhood influenza vaccination coverage remains low in lower/middle-income countries. This systematic review aims to identify influencing factors around childhood influenza vaccination. A systematic literature review was conducted and included empirical studies with original data that investigated factors influencing childhood influenza vaccination. We searched MEDLINE, Web of Science, EMBASE, CINAHL Plus, Global Health, PsycINFO, and two Chinese databases, China Knowledge Resource Integrated Database and Chongqing VIP, using a combination of the key terms ‘childhood’, ‘influenza’, ‘vaccination’, and related syntax for all peer-reviewed publications published before December 2019. Thirty studies were included in the analysis. Childhood influenza vaccination was positively associated with caregivers’ knowledge of influenza vaccine, positive vaccine attitudes, self-efficacy, perceived susceptibility and severity of influenza, believing in the efficacy of influenza vaccine, the worry of getting sick, healthcare workers’ recommendations, and previous influenza vaccination experiences. Barriers included the fear of safety and side effects of the vaccine, as well as poor access to vaccination service. To improve childhood influenza vaccine uptake, health education is necessary to address caregivers’ lack of confidence on vaccine safety. Future studies are needed to investigate influencing factors around healthcare workers’ vaccination recommendation behaviors and the impact of contextual factors on public vaccination behaviors. Full article

(This article belongs to the Special Issue Vaccines against Influenza Virus)

► Show Figures

Figure 1

21 pages, 4506 KiB

Open AccessSystematic Review

Seasonal Influenza Vaccine Effectiveness in Persons Aged 15–64 Years: A Systematic Review and Meta-Analysis

by João Paulo Martins, Marlene Santos, André Martins, Miguel Felgueiras and Rui Santos

Vaccines 2023, 11(8), 1322; https://doi.org/10.3390/vaccines11081322 - 4 Aug 2023

Cited by 7 | Viewed by 4414

Abstract

Influenza is a respiratory disease caused by the influenza virus, which is highly transmissible in humans. This paper presents a systematic review and meta-analysis of randomized controlled trials (RCTs) and test-negative designs (TNDs) to assess the vaccine effectiveness (VE) of seasonal influenza vaccines [...] Read more.

Influenza is a respiratory disease caused by the influenza virus, which is highly transmissible in humans. This paper presents a systematic review and meta-analysis of randomized controlled trials (RCTs) and test-negative designs (TNDs) to assess the vaccine effectiveness (VE) of seasonal influenza vaccines (SIVs) in humans aged 15 to 64 years. An electronic search to identify all relevant studies was performed. The outcome measure of interest was VE on laboratory-confirmed influenza (any strain). Quality assessment was performed using the Cochrane risk-of-bias tool for RCTs and the ROBINS-I tool for TNDs. The search identified a total of 2993 records, but only 123 studies from 73 papers were included in the meta-analysis. Of these studies, 9 were RCTs and 116 were TNDs. The pooled VE was 48% (95% CI: 42–54) for RCTs, 55.4% (95% CI: 43.2–64.9) when there was a match between the vaccine and most prevalent circulating strains and 39.3% (95% CI: 23.5–51.9) otherwise. The TNDs’ adjusted VE was equal to 39.9% (95% CI: 31–48), 45.1 (95% CI: 38.7–50.8) when there was a match and 35.1 (95% CI: 29.0–40.7) otherwise. The match between strains included in the vaccine and strains in circulation is the most important factor in the VE. It increases by more than 25% when there is a match with the most prevalent circulating strains. The laboratorial method for confirmation of influenza is a possible source of bias when estimating VE. Full article

(This article belongs to the Special Issue Vaccines against Influenza Virus)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Vaccines against Influenza Virus

Share This Special Issue

Special Issue Editor

Special Issue Information

Keywords

Benefits of Publishing in a Special Issue

Published Papers (14 papers)

Research

Review

Other

Further Information

Guidelines

MDPI Initiatives

Follow MDPI