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20 pages, 1802 KiB

Open AccessArticle

Global Status of Adult Immunization Post COVID-19 Pandemic

by Alba Vilajeliu, Victor Vega, Randie Gibson, Francisco Nogareda, Xiaojun Wang, Donald J. Brooks, Charles Shey Wiysonge, Osman Niyazi Cakmak, Osama Mere, Melanie Marti, Phillip Lambach, Stephanie Shendale, Marcela Contreras, Emmanuel Njambe, Erin Grace Sparrow, Joachim Hombach and Ann Lindstrand

Vaccines 2025, 13(4), 401; https://doi.org/10.3390/vaccines13040401 - 11 Apr 2025

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Abstract

Background/Objective: Historically, immunization programs have focused on infants, children, and women of reproductive age. COVID-19 vaccination prompted countries to vaccinate adults. The objective of this manuscript is to provide a global overview of adult immunization policies post COVID-19 pandemic. Methods: We summarized WHO [...] Read more.

Background/Objective: Historically, immunization programs have focused on infants, children, and women of reproductive age. COVID-19 vaccination prompted countries to vaccinate adults. The objective of this manuscript is to provide a global overview of adult immunization policies post COVID-19 pandemic. Methods: We summarized WHO Strategic Advisory Group of Experts on Immunization (SAGE) recommendations by adult group and analyzed the data reported in 2024 (2023) by WHO Member States (MS) via the WHO/UNICEF electronic Joint Reporting Form on Immunization (eJRF) on national immunization schedules, and from other sources by WHO region and income group. Results: WHO policy recommendations exist for most of the licensed vaccines targeting adults; however, the inclusion in national immunization schedules is higher in high-income (HICs) and middle-income (MICs) countries. For pregnant women, 90% of MS reported vaccination against COVID-19 (65% in low-income countries [LICs]), 63% against tetanus-containing vaccines (73% in LICs), 57% against influenza (4% in LICs), and 21% against pertussis-containing vaccines (all MICs and HICs). For health workers, 91% against COVID-19 (92% in LICs), 59% against influenza (4% in LICs), and 25% against hepatitis B (10% in LICs). For adults with chronic diseases, COVID-19 vaccination data were not available, 58% against influenza, and 23% against pneumococcal disease. For older adults, more than 90% of MS across all income groups reported COVID-19 vaccination, 59% against influenza (8% of LICs versus 89% of HICs), 17% against pneumococcal, and 7% against herpes zoster (HZ). Conclusion: The disparities in adult immunization policies across income groups highlight the need to improve access and strengthen vaccination efforts. A life course approach is essential to maximize the full potential of immunization across all ages. Full article

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

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13 pages, 1221 KiB

Open AccessArticle

Regional Disparities in HPV Vaccination Coverage Among Girls Aged 9 to 14 Years in Togo: Lessons Learned from the Recent Supplementary Immunization Activities

by Dadja Essoya Landoh, Issifou Yaya, Amevegbe Boko, Kodjovi Adjeoda, Yaovi Temfan Toke, Adidja Amani, Yerima Mouhoudine, Ado Mpia Bwaka, Nsiari-Mueyi Joseph Biey, Charles Shey Wiysonge, Franck Fortune Roland Mboussou, Hèzouwè Looky-Djobo, Tsidi Agbeko Tamekloe, Toyi Nyulelen Mangbassim, Tchasso Kenao, Amadou Bailo Diallo, Fatoumata Binta Tidiane Diallo, Benido Impouma, Ann Lindstrand, Marin Kokou Wotobe and Didier Koumavi Ekouevi Show full author list Hide full author list

Vaccines 2025, 13(4), 373; https://doi.org/10.3390/vaccines13040373 - 31 Mar 2025

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Abstract

Background/Objectives: Human papillomavirus (HPV) vaccination is a critical intervention to prevent cervical cancer, especially in settings where screening is limited. In Togo, cervical cancer is the second most common cancer in women. Togo conducted an HPV vaccination campaign for girls aged 9–14 from [...] Read more.

Background/Objectives: Human papillomavirus (HPV) vaccination is a critical intervention to prevent cervical cancer, especially in settings where screening is limited. In Togo, cervical cancer is the second most common cancer in women. Togo conducted an HPV vaccination campaign for girls aged 9–14 from 27 November to 1 December 2023, followed by introduction of the vaccine into routine immunization. This study aimed to assess regional disparities in vaccination coverage during this campaign. Methods: A cross-sectional study was conducted using data from the nationwide HPV vaccination campaign. The target population included girls aged 9–14, following school and community-based enumeration. The campaign employed school-based, health facility-based, and community-based vaccination strategies. Data were collected via multiple tools, and monitoring was carried out through daily reports and digital tracking. Results: Out of the estimated 654,402 eligible girls, 304,457 (46.5%) were vaccinated. Vaccine coverage varied significantly by region, ranging from 76% in Kara to 15% in Grand Lomé. In-school settings accounted for 91.3% of vaccinations, with the fixed strategy covering 55.4%. In total, 11 districts exceeded 80% vaccine coverage, while 15 districts had <50%. The highest rate of adverse events following immunization was observed in the Maritime region, primarily involving minor symptoms. Conclusion: Although progress was made in HPV vaccination coverage in Togo, regional disparities highlight the need for targeted interventions. Strategies such as expanding vaccine access, enhancing awareness campaigns, and integrating HPV vaccination into routine immunization could improve coverage. Addressing logistical and cultural barriers is also crucial for equitable vaccination, aiming to achieve international benchmarks and reduce HPV-related disease burdens. Further research should explore qualitative factors influencing vaccine acceptance. Full article

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

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16 pages, 533 KiB

Open AccessArticle

Impact of Measles, Mumps, and Rubella Vaccination on Hospitalizations and Human Capital: Evidence from Copenhagen School Health Records

by Onur Altindag, Jane Greve and Erdal Tekin

Vaccines 2025, 13(3), 302; https://doi.org/10.3390/vaccines13030302 - 11 Mar 2025

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Abstract

Background: This paper investigates the long-term effects of the measles, mumps, and rubella (MMR) vaccine on healthcare, education, and economic outcomes using a novel dataset from the Copenhagen School Health Records Register. Methods: To address potential endogeneity, we use within-sibling variation in vaccination [...] Read more.

Background: This paper investigates the long-term effects of the measles, mumps, and rubella (MMR) vaccine on healthcare, education, and economic outcomes using a novel dataset from the Copenhagen School Health Records Register. Methods: To address potential endogeneity, we use within-sibling variation in vaccination status induced by different periods of vaccine availability in Denmark. Results: Our findings reveal that, prior to the establishment of herd immunity, vaccinated cohorts experienced substantial protection against hospitalizations related to MMR. During the same period, we also observe modest improvements in educational outcomes and positive—though statistically insignificant—estimates for labor market outcomes among siblings with discordant vaccination status. We find no impact of vaccination on hospitalizations, education, or economic outcomes for cohorts born after herd immunity was established, a period when everyone benefited from herd protection regardless of individual vaccination status. Conclusions: MMR vaccination, before herd immunity, reduced hospitalization due to Measles, Mumps, and Rubella. The impact on later outcomes, such as education, income, and employment lacks statistical precision at conventional levels. Evidence suggest positive self-selection in vaccination among families with high socioeconomic status. Full article

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

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11 pages, 1369 KiB

Open AccessArticle

Strengthening National Immunization Technical Advisory Groups: Twelve Years of Progress (2012–2023)

by Louise Henaff, Laure Dumolard, Vinod Bura, Gerald Etapelong Sume, Sidy Ndiaye, Jennifer Sanwogou, Heeyoun Cho, Joachim Hombach and Christoph A. Steffen

Vaccines 2025, 13(1), 80; https://doi.org/10.3390/vaccines13010080 - 17 Jan 2025

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Abstract

Introduction: Well-functioning National Immunization Technical Advisory Groups (NITAGs) are valuable contributors to decision-making processes in the complex immunization policy arena. This paper describes the progress made globally on the establishment and strengthening of these key advisory groups and discusses some of their strengths, [...] Read more.

Introduction: Well-functioning National Immunization Technical Advisory Groups (NITAGs) are valuable contributors to decision-making processes in the complex immunization policy arena. This paper describes the progress made globally on the establishment and strengthening of these key advisory groups and discusses some of their strengths, challenges, and opportunities. Methods: The data submitted annually by countries to the World Health Organization (WHO) via the WHO/UNICEF Joint Reporting Form (JRF) were analyzed, comparing the NITAG functionality criteria in 2012 and 2023. Results: In 2023 and 2012, 88% and 61% of countries, respectively, reported having a NITAG. A total of 77% of NITAGs met all six NITAG process criteria in 2023 compared to 33% in 2012. This progress was most notable in the WHO African Region, increasing from 7% (2012) to 77% (2023), and the South-East Asia Region, increasing from 45% (2012) to 91% (2023). In 2023, 84% of NITAGs issued a vaccine-policy recommendation that was adopted by decision-makers. Discussion: Marked progress has been made since 2012 on establishing and maintaining NITAGs, with a small number of countries yet to form an advisory committee. Supporting and sustaining NITAG functions remains an important means for countries to foster independent and transparent expert advice on vaccine and immunization policy. Setbacks in countries facing instability or political turmoil are a reminder of the reversibility of progress. WHO and partners play an important role in supporting countries in strengthening these advisory committees. Continuous commitment by countries to the function and involvement of NITAGs in policy recommendations is essential for enhancing the strength and resilience of immunization programs. Full article

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

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20 pages, 2608 KiB

Open AccessArticle

Using Human-Centered Design to Bridge Zero-Dose Vaccine Gap: A Case Study of Ilala District in Tanzania

by Simon Martin Nzilibili, Hellen Maziku, Awet Araya, Ruthbetha Kateule, Millenium Anthony Malamla, Suna Salum, Furaha Kyesi, Lotalis Gadau, Tumaini Menson Haonga, Florian Tinuga, Rashid Mfaume, Zaitun Hamza, Georgina Joachim, Alice Geofrey Mwiru, Alex Benson, Oscar Kapela, Ona Machangu, Norman Jonas and Ntuli Kapologwe

Vaccines 2025, 13(1), 38; https://doi.org/10.3390/vaccines13010038 - 6 Jan 2025

Cited by 1 | Viewed by 1521

Abstract

Background: Immunization plays a substantial role in reducing the under-five mortality rate. However, Tanzania still has a significant number of zero-dose and under-vaccinated children and was ranked among the top ten African countries with the highest numbers of zero-dose children in 2022. The [...] Read more.

Background: Immunization plays a substantial role in reducing the under-five mortality rate. However, Tanzania still has a significant number of zero-dose and under-vaccinated children and was ranked among the top ten African countries with the highest numbers of zero-dose children in 2022. The human-centered design (HCD) approach is more ethical and effective at addressing public health challenges in complex sociocultural settings. This study aimed to use the HCD approach to aid in identifying, prioritizing, and implementing community-centric interventions in Tanzania, particularly in the Ilala District of Dar es Salaam, to increase vaccine demand and close the zero-dose gap by at least 50%. Methods: The study involved co-creation workshops with 483 participants to identify, design, and test solutions. The study followed the UNICEF Journey to Health and Immunization framework to identify barriers and enablers influencing stakeholders in adopting and sustaining health- and immunization-related actions. Results: The study identified the causes of under-five defaulting and the zero-dose gap, i.e., the inadequate support of local community leaders in under-five vaccination sensitization and surveillance; poor infrastructure to new settlement areas; hesitancy and unwillingness of parents/guardians; absence of house numbers; limited/time-constrained availability of resources to facilitate mobile immunization services, etc. The participants were able to come up with 309 ideas, which were refined through multiple iterations using the impact–-effort matrix and skimmed down to three (3) solutions: (i) having health facilities to notify and alert local leaders about vaccination dates; (ii) using parents, kids, and grownups who got vaccinated to influence others; (iii) using local government leaders and house representatives for vaccine advocacy. Of these, the solution involving local government leaders and house representatives for vaccine advocacy was implemented. An advocacy strategy was used to enhance the collaboration of the District Commissioner, Council leaders, and community leaders. A home-to-home interpersonal sensitization approach accompanied by the household delivery of vaccination services was employed. The findings reveal that the HCD framework was impactful in increasing collaborations/cooperation with local government leaders and community ownership of the under-five vaccination initiative. As a result, 67,145 houses, equal to 104%, were reached, surpassing the initial target of 64,800 houses, and 131,088 families, equal to 83% of the targeted 156,995 households, were sensitized through a home-to-home campaign approach. This study demonstrates the effectiveness of the approach. Researchers and practitioners are encouraged to adopt the HCD approach when addressing public health challenges, especially in complex sociocultural settings. Full article

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

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12 pages, 230 KiB

Open AccessArticle

COVID-19 Vaccine Hesitancy Among Pediatric Oncology and Bone Marrow Transplant Patients

by Sarah A. O’Neill, Son Tran, Cora Constantinescu and Tony H. Truong

Vaccines 2024, 12(12), 1407; https://doi.org/10.3390/vaccines12121407 - 13 Dec 2024

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Abstract

Background/Objectives: Vaccine hesitancy among immunocompromised patients is complex and not well understood. This study aimed to determine the rate of COVID-19 vaccine hesitancy among pediatric oncology and bone marrow transplant (BMT) patients and to understand associated factors. Methods: Parents of patients (≤18 [...] Read more.

Background/Objectives: Vaccine hesitancy among immunocompromised patients is complex and not well understood. This study aimed to determine the rate of COVID-19 vaccine hesitancy among pediatric oncology and bone marrow transplant (BMT) patients and to understand associated factors. Methods: Parents of patients (≤18 years) with cancer or post-BMT completed the Parent Attitudes about Childhood Vaccines Survey. A COVID-19 vaccine hesitancy score (VHS-COVID) was calculated from 0 to 100 (higher scores indicating increasing hesitancy). A small group of patients (patients older than 15 years) were also surveyed directly. Results: Among 113 parent respondents, the majority were female (58%) and at least college/university educated (78%). The majority (73%) of patients had cancer (61% leukemia/lymphoma, 37% solid/CNS tumors), while 27% had received BMT for malignant and non-malignant conditions. Only 48% of patients had been vaccinated against COVID-19, compared to 88% of parents. Ineligibility due to phase of cancer/BMT treatment (27%), vaccine hesitancy (24%), and age (24%) were the top three reasons for not vaccinating against COVID-19. Only 13% of parents said they would “definitely vaccinate” if their child became eligible. VHS-COVID scores were higher for parents of patients in surveillance versus active therapy (mean 61 vs. 48; p = 0.03). Parents who had received fewer COVID-19 vaccine doses (0–1 vs. ≥2) were more hesitant toward all vaccines (p = 0.0002), COVID-19 vaccines (p = 0.0003), and influenza vaccines (p = 0.005). Conclusions: Vaccine hesitancy is common among this population and was demonstrated through beliefs (hesitancy scores) as well as vaccine uptake. Future work should focus on education targeting vaccine eligibility and engaging with vaccine hesitant families in the immunocompromised community. Full article

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

13 pages, 3255 KiB

Open AccessArticle

Addressing Barriers Newcomer Families Face When Obtaining Routine Childhood Vaccines in Alberta, Canada

by Siobhan M. Wong King Yuen, Emily J. Doucette, Caitlin Ford, Madison M. Fullerton, Ginamaria Vetro, Amanda Koyama, Jia Hu and Cora Constantinescu

Vaccines 2024, 12(12), 1380; https://doi.org/10.3390/vaccines12121380 - 7 Dec 2024

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Abstract

Background/Objectives: As the newcomer population in Canada continues to grow, we aimed to collaborate with newcomer families arriving in an urban center in Alberta, Canada to identify strategies to overcome identified barriers newcomers face in obtaining routine childhood vaccines (RCVs). Methods: [...] Read more.

Background/Objectives: As the newcomer population in Canada continues to grow, we aimed to collaborate with newcomer families arriving in an urban center in Alberta, Canada to identify strategies to overcome identified barriers newcomers face in obtaining routine childhood vaccines (RCVs). Methods: We recruited newcomers living in Calgary, Alberta to participate in a workshop utilizing the Nominal Group Technique (NGT) to develop solutions addressing barriers to obtaining RCVs. Ranking exercises helped identify the top-proposed interventions based on perceived impact and feasibility for implementation. Based on the identified need for translated vaccine resources, infographics on school-based vaccines were developed. The infographics were pilot-tested in a first-language focus group before the final product was translated into 10 different languages. Results: Consensus from 15 NGT workshop participants identified five key solutions to facilitate obtaining routine childhood immunizations: (1) Increasing access to reliable vaccine information; (2) Ensuring vaccine information and healthcare services are available in different languages; (3) Increasing vaccine appointment availability and optimizing the booking system for ease of navigation; (4) Increasing the role of family doctors in vaccine counseling and administration; (5) Streamlining vaccine record tracking. We developed infographics on the vaccines children in Alberta can receive through school-based vaccine programs and these were pilot-tested with 16 participants in a first-language (Arabic) focus group. Conclusions: The collaborative and iterative process of solution development with newcomers provided a platform for knowledge translation through the development of educational resources on school-based vaccines, addressing the information barrier that newcomers identified when accessing RCVs. Full article

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

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12 pages, 590 KiB

Open AccessArticle

Routine Immunization Microplanning Challenges and Opportunities in Low- and Middle-Income Countries: A Mixed-Method Landscape Analysis

by Nicole Salisbury, Iqbal Hossain, Parysa Oskouipour, Audry Hong, Elan Ebeling, Jessica C. Shearer and Emily Grapa

Vaccines 2024, 12(12), 1370; https://doi.org/10.3390/vaccines12121370 - 4 Dec 2024

Viewed by 2006

Abstract

Background: Microplanning is widely recognized as a critical tool for improving immunization coverage and equity and is considered a core component of routine immunization. However, there is limited evidence on how microplans are developed and implemented and the effectiveness of microplanning. As such, [...] Read more.

Background: Microplanning is widely recognized as a critical tool for improving immunization coverage and equity and is considered a core component of routine immunization. However, there is limited evidence on how microplans are developed and implemented and the effectiveness of microplanning. As such, this study sought to review the existing evidence on implementation and institutionalization of microplanning; identify strategies to improve microplanning; and document evidence on new approaches to microplanning, including digitally enhanced and integrated microplanning. Methods: We employed a three-stage mixed-method approach. First, we conducted a literature review on microplanning for routine immunization. Second, we administered an online survey to gather insights into the factors that constrained and enabled microplanning in low-resource settings. Third, we conducted key informant interviews to better understand the barriers and enablers. Results: We found a paucity of published literature describing the drivers and effectiveness of microplanning and how to sustain it over time. Our review indicates that factors at both the development and implementation stages influence implementation and whether the process is sustained over time. These include the level of community engagement and health care worker ownership, access to data, the complexity of the microplanning tools, and the extent to which supervisors follow up on the plans. Conclusion: Our review indicates that microplanning is successful when health care workers and communities are engaged in the development process. While these findings highlight the benefits of a ‘bottom-up’ approach to microplanning, this may be more resource-intensive, and there remains a need for more research on the costs and benefits. Full article

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

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11 pages, 1250 KiB

Open AccessArticle

Securing the Future: Strategies for Global Polio Vaccine Security Amid Eradication Efforts

by Vachagan Harutyunyan, Ann Ottosen, Rachel M. Burke, Derek Ehrhardt, Meredith Shirey, Rissa Durham and David Woods

Vaccines 2024, 12(12), 1369; https://doi.org/10.3390/vaccines12121369 - 4 Dec 2024

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Abstract

Background/Objectives: As we commemorate 50 years of the Expanded Programme on Immunization (EPI), the global mission to eradicate polio stands at a critical juncture. While remarkable progress has been made over the past decades, ensuring a steady supply of polio vaccines remains a [...] Read more.

Background/Objectives: As we commemorate 50 years of the Expanded Programme on Immunization (EPI), the global mission to eradicate polio stands at a critical juncture. While remarkable progress has been made over the past decades, ensuring a steady supply of polio vaccines remains a significant challenge that could undermine these achievements. This manuscript aims to address the complexities of polio vaccine security within the context of the Immunization Agenda 2030 (IA2030) and the Global Polio Eradication Strategy 2022–2029, proposing actionable strategies to strengthen the vaccine supply. Methods: This manuscript analyzes obstacles to vaccine security, including supply disruptions and market uncertainties. It presents the Polio Vaccine Security Framework as a key strategy for addressing these challenges. Data were gathered from Global Polio Eradication Initiative (GPEI) reports, consultations with key stakeholders, and analyses of past vaccine shortages. Results: The findings indicate that the primary risks to vaccine security include the lack of a coherent long-term policy framework on polio vaccination, the absence of a clear polio vaccine development roadmap, and insufficient long-term, predictable forecasting. Additionally, stronger coordination is needed between stakeholders involved in vaccine supply, polio containment, and research, as well as addressing challenges related to financing and access to resources. Conclusions: A robust, adaptable, and sustainable approach to vaccine security, proposed in the Polio Vaccine Security Framework, is critical to achieving and sustaining polio eradication. Collaboration among policymakers, manufacturers, and stakeholders to implement it is essential to ensure the uninterrupted supply of polio vaccines, protecting the progress made over the past half century, and preventing a resurgence of poliovirus in the future. Full article

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

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10 pages, 220 KiB

Open AccessArticle

The Costs and Cost-Effectiveness of a Two-Dose Oral Cholera Vaccination Campaign: A Case Study in a Refugee Camp Setting in Thailand

by Aaron S. Wallace, Kashmira Date, Sarah W. Pallas, Nuttapong Wongjindanon, Christina R. Phares and Taiwo Abimbola

Vaccines 2024, 12(11), 1235; https://doi.org/10.3390/vaccines12111235 - 30 Oct 2024

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Abstract

Oral cholera vaccination (OCV) campaigns are increasingly used to prevent cholera outbreaks; however, little is known about their cost-effectiveness in refugee camps. We conducted a cost-effectiveness analysis of a pre-emptive OCV campaign in the Maela refugee camp in Thailand, where outbreaks occurred with [...] Read more.

Oral cholera vaccination (OCV) campaigns are increasingly used to prevent cholera outbreaks; however, little is known about their cost-effectiveness in refugee camps. We conducted a cost-effectiveness analysis of a pre-emptive OCV campaign in the Maela refugee camp in Thailand, where outbreaks occurred with an annual incidence rate (IR) of up to 10.7 cases per 1000. Data were collected via health sector records and interviews and household interviews. In the base-case scenario comparing the OCV campaign with no campaign, we estimated the campaign effect on the cholera IR and case fatality rate (CFR: 0.09%) from a static cohort model and calculated incremental cost-effectiveness ratios for the outcomes of death, disability-adjusted life-years (DALYs), and cases averted. In sensitivity analyses, we varied the CFR and IR. The household economic cost of illness was USD 21, and the health sector economic cost of illness was USD 51 per case. The OCV campaign economic cost was USD 289,561, 42% attributable to vaccine costs and 58% to service delivery costs. In our base case, the incremental cost was USD 1.9 million per death averted, USD 1745 per case averted, and USD 69,892 per DALY averted. Sensitivity analyses that increased the CFR to 0.35% or the IR to 10.4 cases per 1000 resulted in a cost per DALY of USD 15,666. The low multi-year average CFR and incidence of the cholera outbreaks in the Maela camp were key factors associated with the high cost per DALY averted. However, the sensitivity analyses indicated higher cost-effectiveness in a setting with a higher CFR or cholera incidence, indicating when to consider campaign use to reduce the outbreak risk. Full article

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

14 pages, 1848 KiB

Open AccessArticle

Spectrum and Incidence of Adverse Reactions Post Immunization in the Taiwanese Population (2014–2019): An Analysis Using the National Vaccine Injury Compensation Program

by Wan-Chun Lai, Chin-Hui Yang, Yhu-Chering Huang, Nan-Cheng Chiu and Chih-Jung Chen

Vaccines 2024, 12(10), 1133; https://doi.org/10.3390/vaccines12101133 - 3 Oct 2024

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Abstract

Background: Post-marketing surveillance is crucial for gathering data on vaccine reactogenicity, enhancing public trust in immunization, and promoting vaccine uptake. This study aims to characterize adverse events following immunization (AEFIs) and estimate the incidence rates of adverse reactions (ARs) associated with vaccines [...] Read more.

Background: Post-marketing surveillance is crucial for gathering data on vaccine reactogenicity, enhancing public trust in immunization, and promoting vaccine uptake. This study aims to characterize adverse events following immunization (AEFIs) and estimate the incidence rates of adverse reactions (ARs) associated with vaccines included in Taiwan’s Expanded Program on Immunization (EPI). This study utilizes data from Taiwan’s Vaccine Injury Compensation Program (VICP). Methods: Vaccine injury claims submitted to the VICP between 2014 and 2019 were analyzed. ARs were defined as AEFIs adjudicated as “related” or “indeterminate” by the VICP committee. Data on the annual number of vaccine doses administered were obtained from the Taiwan CDC, which helped calculate the AR incidence rates. Results: A total of 491 AEFI claims were reviewed, with 327 (66.6%) categorized as ARs. The AEFIs were mainly associated with the Bacillus Calmette–Guérin (BCG) vaccine (43.4%) and the seasonal influenza vaccine (22.0%). Most EPI vaccines demonstrated low AR incidence rates, ranging from 1.68 to 13.6 per million doses, with the exception of BCG, which exhibited 162.5 ARs per million doses. Shifting BCG immunization from below 5 months to at least 5 months reduced osteomyelitis incidence significantly, from 41.4 to 7.9 (p = 0.0014), but increased abscess and lymphadenitis cases. Conclusions: EPI vaccines in Taiwan are highly safe, with minimal AR incidences in the general population. The BCG vaccine remains an exception, occasionally causing severe ARs like osteomyelitis. Adjusting the immunization schedule to an older age may mitigate some of these adverse effects. Full article

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

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12 pages, 238 KiB

Open AccessArticle

COVID-19 Vaccine Hesitancy and Associated Oral Cholera Vaccine Hesitancy in a Cholera-Endemic Country: A Community-Based Cross-Sectional Study in the Democratic Republic of Congo

by Arsene Daniel Nyalundja, Patrick Musole Bugeme, Alain Balola Ntaboba, Victoire Urbain Hatu’m, Guillaume Shamamba Ashuza, Jacques Lukenze Tamuzi, Duduzile Ndwandwe, Chinwe Iwu-Jaja, Charles Shey Wiysonge and Patrick D. M. C. Katoto

Vaccines 2024, 12(4), 444; https://doi.org/10.3390/vaccines12040444 - 22 Apr 2024

Cited by 2 | Viewed by 1928

Abstract

COVID-19 vaccine hesitancy and its enablers shape community uptake of non-covid vaccines such as the oral cholera vaccine (OCV) in the post-COVID-19 era. This study assessed the impact of COVID-19 vaccine hesitancy and its drivers on OCV hesitancy in a cholera-endemic region of [...] Read more.

COVID-19 vaccine hesitancy and its enablers shape community uptake of non-covid vaccines such as the oral cholera vaccine (OCV) in the post-COVID-19 era. This study assessed the impact of COVID-19 vaccine hesitancy and its drivers on OCV hesitancy in a cholera-endemic region of the Democratic Republic of Congo. We conducted a community-based survey in Bukavu. The survey included demographics, intention to take OCV and COVID-19 vaccines, reasons for COVID-19 hesitancy, and thoughts and feelings about COVID-19 vaccines. Poisson regression analyses were performed. Of the 1708 respondents, 84.66% and 77.57% were hesitant to OCV alone and to both OCV and COVID-19, respectively. Hesitancy to COVID-19 vaccines rose OCV hesitancy by 12% (crude prevalence ratio, [cPR] = 1.12, 95%CI [1.03–1.21]). Independent predictors of OCV hesitancy were living in a semi-urban area (adjusted prevalence ratio [aPR] = 1.10, 95%CI [1.03–1.12]), religious refusal of vaccines (aPR = 1.06, 95%CI [1.02–1.12]), concerns about vaccine safety (aPR = 1.05, 95%CI [1.01–1.11]) and adverse effects (aPR = 1.06, 95%CI [1.01–1.12]), as well as poor vaccine literacy (aPR = 1.07, 95%CI [1.01–1.14]). Interestingly, the belief in COVID-19 vaccine effectiveness reduced OCV hesitancy by 24% (aPR = 0.76, 95%CI [0.62–0.93]). COVID-19 vaccine hesitancy and its drivers exhibited a significant domino effect on OCV uptake. Addressing vaccine hesitancy through community-based health literacy and trust-building interventions would likely improve the introduction of novel non-COVID-19 vaccines in the post-COVID-19 era. Full article

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

Review

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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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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

Cited by 2 | Viewed by 1465

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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15 pages, 1318 KiB

Open AccessReview

The Strategic Advisory Group of Experts (SAGE) on Immunization—Past, Present and Future

by Melanie Marti, Hanna Nohynek, Philippe Duclos, Katherine L. O’Brien and Joachim Hombach

Vaccines 2024, 12(12), 1402; https://doi.org/10.3390/vaccines12121402 - 12 Dec 2024

Cited by 3 | Viewed by 5717

Abstract

Background/Objectives: In November 1999, WHO established the Strategic Advisory Group of Experts (SAGE) on Immunization as a multidisciplinary group of experts to provide high-level recommendations on vaccines and immunization. Methods: This review provides an overview of SAGE’s work in the past 25 years. [...] Read more.

Background/Objectives: In November 1999, WHO established the Strategic Advisory Group of Experts (SAGE) on Immunization as a multidisciplinary group of experts to provide high-level recommendations on vaccines and immunization. Methods: This review provides an overview of SAGE’s work in the past 25 years. It further outlines the processes and methods currently used by SAGE and highlights some of its major achievements. Results: SAGE’s global policies have driven action toward eradication, elimination and disease control and addressed the optimization of vaccination and immunization. In total, 27 major policy positions on vaccines/vaccine-preventable diseases have guided global public health. During times of epidemics and pandemics, interim recommendations issued by SAGE have responded iteratively in real-time to provide evidence-driven response policies. SAGE is an adaptive advisory group that has modified its procedures and working approaches to meet the evolving challenges in public health and stay up-to-date with evolving scientific and guideline development standards. Conclusions: Over the last quarter century, SAGE has significantly contributed to shaping the immunization landscape. It has achieved and maintained a high level of integrity and credibility. The advisory group continues to be an authority in global public health, and its recommendations have profound implications for the health of individuals and populations across the globe. Full article

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

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16 pages, 238 KiB

Open AccessConference Report

WHO Workshop Report: Regulatory Science to Inform Clinical Pathways for Shigella Vaccines Intended for Use in Children in Low- and Middle-Income Countries

by Robert W. Kaminski, Patricia B. Pavlinac, James A. Platts-Mills, Elizabeth T. Rogawski McQuade, William P. Hausdorff, Richard A. Isbrucker, Kirsten S. Vannice, Marco Cavaleri, Sonali Kochhar, Kirsty Mehring-LeDoare, Godwin Enwere, Annelies Wilder-Smith, Karen L. Kotloff, Samba Sow and Birgitte K. Giersing

Vaccines 2025, 13(5), 439; https://doi.org/10.3390/vaccines13050439 - 23 Apr 2025

Abstract

Infectious diarrhea caused by Shigella remains a significant global health concern, and several vaccine candidates are approaching phase III clinical studies in the target population of young children in low- and middle-income countries. The World Health Organization (WHO) has published preferred product characteristics [...] Read more.

Infectious diarrhea caused by Shigella remains a significant global health concern, and several vaccine candidates are approaching phase III clinical studies in the target population of young children in low- and middle-income countries. The World Health Organization (WHO) has published preferred product characteristics (PPCs) for Shigella vaccines to provide strategic guidance that aids in advancing product development and highlights policy considerations for use in LMIC settings where the vaccine is most needed. However, the selection of appropriate clinical endpoints was not clearly defined within the PPCs and remains an important issue for phase III study design. Previously, an expert panel identified areas of alignment and consensus on many clinical study design components while also recognizing that further discussions and data were required to solidify recommendations on key study design aspects. Therefore, WHO convened a diverse range of stakeholders, including manufacturers, regulators, and policymakers across national, regional, and global levels, with the aim of achieving consensus and soliciting inputs from the regulatory community surrounding vaccine phase III study design considerations. The intent of this report is to outline the key points from those discussions to inform the phase III design strategies and investment decisions of product developers and donors and to share recommendations for next steps. Full article

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

22 pages, 878 KiB

Open AccessSystematic Review

Immunization Coverage, Equity, and Access for Children with Disabilities: A Scoping Review of Challenges, Strategies, and Lessons Learned to Reduce the Number of Zero-Dose Children

by Godfrey Musuka, Diego F. Cuadros, F. DeWolfe Miller, Zindoga Mukandavire, Tapiwa Dhliwayo, Patrick Gad Iradukunda, Oscar Mano and Tafadzwa Dzinamarira

Vaccines 2025, 13(4), 377; https://doi.org/10.3390/vaccines13040377 - 31 Mar 2025

Viewed by 444

Abstract

Background: Children with disabilities, particularly in low- and middle-income countries (LMICs), face heightened risks of vaccine-preventable diseases due to a range of systemic and social barriers. Although immunization is a fundamental human right and a proven public health intervention, this vulnerable group [...] Read more.

Background: Children with disabilities, particularly in low- and middle-income countries (LMICs), face heightened risks of vaccine-preventable diseases due to a range of systemic and social barriers. Although immunization is a fundamental human right and a proven public health intervention, this vulnerable group is often overlooked in policy and practice. Understanding the factors compromising vaccine equity for these children is critical to reducing zero-dose prevalence and improving health outcomes. Methods: This scoping review examined peer-reviewed, gray literature from 2010 to 2024. Searches were conducted in PubMed, Google Scholar, and relevant organizational reports (WHO, UNICEF). Studies addressing children with disabilities and focusing on immunization barriers, interventions, or lessons learned were selected. English-language publications were screened in title/abstract and full-text stages. Key data extracted included population, barriers, and immunization outcomes. Since this review focused on articles in English, this is a key limitation. Results were synthesized thematically to identify recurring patterns and to guide improved interventions and policies. Results: Twelve articles met the inclusion criteria. Key barriers identified were inadequate healthcare infrastructure, insufficient provider training, limited follow-up services in rural regions, societal stigma, and pervasive misconceptions around both disability and vaccines. Factors such as maternal education, logistical support for caregivers, and using low-sensory, inclusive vaccination settings were consistently linked with better outcomes. Effective strategies included mobile vaccination units, tailored interventions (e.g., distraction or sedation techniques), school-based immunization programs, and robust community engagement to address stigma. Lessons learned underscored the importance of flexible, individualized care plans and empowering families through transparent communication. Conclusions: Children with disabilities continue to experience significant gaps in immunization coverage, driven by intersecting barriers at the individual, health system, and societal levels. Scaling tailored interventions, inclusive policies, strengthened infrastructure, and ongoing research can help ensure these children receive equitable access to life-saving vaccinations. Full article

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

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9 pages, 354 KiB

Open AccessConference Report

The 2024 Annual Meeting of the Essential Programmes on Immunization Managers in Central Africa: A Peer Learning Platform

by Franck Mboussou, Audry Mulumba, Celestin Traore, Florence Conteh-Nordman, Shalom Tchokfe Ndoula, Antoinette Demian Mbailamen, Jean Claude Bizimana, Christian Akani, Yolande Vuo-Masembe, Bridget Farham, Marcelin Menguo Nimpa, Thomas Noel Gaha, Martin Morand, Lynda Rey, Maria Carolina Danovaro-Holliday, Charles Shey Wiysonge and Benido Impouma

Vaccines 2025, 13(3), 301; https://doi.org/10.3390/vaccines13030301 - 11 Mar 2025

Viewed by 518

Abstract

Background: Since 1974, Essential Programme on Immunisation managers from ten Central African countries meet yearly with partners to review progress made and share experiences and lessons learned from the implementation of immunization programmes. The 2024 meeting occurred in Kinshasa, Democratic Republic of Congo, [...] Read more.

Background: Since 1974, Essential Programme on Immunisation managers from ten Central African countries meet yearly with partners to review progress made and share experiences and lessons learned from the implementation of immunization programmes. The 2024 meeting occurred in Kinshasa, Democratic Republic of Congo, in September 2024. This conference report summarizes the key takeaways from discussions on using immunization data for decision-making, the implementation of the Big Catch-Up (BCU) initiative to reduce the burden of zero-dose children, and progress and challenges in introducing selected new vaccines. Conference Takeaways: Inaccurate administrative data on routine immunization observed in most countries, compared to WHO/UNICEF Estimates of National Immunization Coverage and national survey estimates, affect timely decisions to improve the Expanded Programme on Immunization (EPI) performance. Five countries in Central Africa are among the priority countries of the BCU initiative but, as of the end of August 2024, are yet to formally start its implementation. Cameroon and Central African Republic introduced the malaria vaccine in January 2024 and August 2024, respectively, while the Democratic Republic of Congo, Chad, and Burundi have planned to do so by 2025. Conclusions and Recommendations: Meeting participants put forward several recommendations for countries and immunization partners, including but not limited to (i) investing more in routine immunization data quality assurance to better use data to inform decisions, (ii) accelerating the implementation of the BCU initiative to close the immunity gap resulting from routine immunization disruptions due to the COVID-19 pandemic, (iii) updating malaria vaccine introduction plans to invest more in demand generation and community engagement, and (iv) learning from Cameroon’s experience in tackling hesitancy to human papilloma virus vaccine. It is critical to set up an appropriate mechanism for monitoring the implementation of these recommendations. Full article

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

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20 pages, 3294 KiB

Open AccessSystematic Review

Evaluating the Immunogenicity, Efficacy, and Effectiveness of Recombinant Zoster Vaccine for Global Public Health Policy

by Lucy R. Williams, Joachim Hombach and Melanie Marti

Vaccines 2025, 13(3), 250; https://doi.org/10.3390/vaccines13030250 - 27 Feb 2025

Viewed by 612

Abstract

Background: Herpes zoster (HZ) is a painful neurocutaneous disease caused by the varicella-zoster virus. The recombinant zoster vaccine (RZV) is becoming increasingly incorporated into national vaccination schedules. We aimed to evaluate RZV from a global public health policy perspective. Methods: We [...] Read more.

Background: Herpes zoster (HZ) is a painful neurocutaneous disease caused by the varicella-zoster virus. The recombinant zoster vaccine (RZV) is becoming increasingly incorporated into national vaccination schedules. We aimed to evaluate RZV from a global public health policy perspective. Methods: We performed a rapid review of studies evaluating the immunogenicity, efficacy, and effectiveness of RZV for protection against HZ and associated complications. We searched PubMed for English-language studies published between 7 August 2012 and 30 September 2023. Included studies reported vaccine efficacy or effectiveness against HZ and HZ-associated complications. Immunogenicity studies were included if they contributed to the understanding of RZV protection over time and/or co-administration with other vaccines. HZ outcomes were stratified by socio-demographic and clinical variables. Results: From 405 identified publications, 33 were eligible for the study. Most studies were conducted in the US (N = 12), across North America (N = 10), and Europe (N = 5), or across multiple locations across North America, Latin America, and Asia–Australia (N = 6). Vaccine efficacy against HZ in immunocompetent populations ranged between 90% and 97%, while effectiveness ranged between 71% and 86%. Protection stayed above 70% for at least 10 years, with no significant differences by age or ethnicity. Conclusions: RZV is effective in reducing the risk of HZ and its associated complications. Protection is long-lasting and the vaccine is suitable for older and immunocompromised populations. However, the decision to incorporate the vaccine into national policies depends on additional factors (e.g., cost-effectiveness), which may be difficult to characterize without an understanding of the global disease burden. Full article

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

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11 pages, 736 KiB

Open AccessCommentary

Missed Measles Immunisations Places Individuals and Communities at Risk: The Equity Argument for Including Measles in Under-Immunised Definitions

by Stefanie Vaccher, Moses Laman, Margie Danchin, Fiona Angrisano and Christopher Morgan

Vaccines 2025, 13(2), 108; https://doi.org/10.3390/vaccines13020108 - 22 Jan 2025

Viewed by 1130

Abstract

Background: Measles is consistently one of the leading causes of death from vaccine-preventable diseases in children, and cases and deaths have increased globally since 2019. While measles often serves as a ‘canary in the coalmine’ for health system weaknesses, global definitions of zero-dose [...] Read more.

Background: Measles is consistently one of the leading causes of death from vaccine-preventable diseases in children, and cases and deaths have increased globally since 2019. While measles often serves as a ‘canary in the coalmine’ for health system weaknesses, global definitions of zero-dose and under-immunised children continue to centre on those who have missed diphtheria-tetanus-pertussis (DTP) containing vaccine. We propose that lack of receipt of measles vaccine is included in global definitions of ‘under-immunised’ children. Methods: We used publicly available WHO/UNICEF estimates of national immunization coverage (WUENIC) data to determine the number and proportion of children missing out on routine immunisations in each country globally in 2019 and 2022. We stratified countries by income status to further investigate inequalities in vaccine coverage between different countries. Results: In 2022, 50% more children missed out on their first dose measles-containing vaccine compared to DTP1, and 96% of these children resided in low-middle income countries (LMICs), highlighting the compounding inequities in measles immunisations globally. Furthermore, countries with the largest number of children missing out on DTP1 were not reflective of countries with the lowest measles immunisation coverage rates, suggesting targeted programs are needed to reach children who are missing out on measles vaccination. Recommendations: Given the high transmissibility and inequitable burden measles outbreaks pose to both at-risk individuals and communities, especially in LMICs, measles immunisation coverage should be included as a key metric when reporting and estimating the number of under-immunised children globally. Full article

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

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14 pages, 1014 KiB

Open AccessSystematic Review

Immunogenicity, Efficacy, and Effectiveness of Two-Dose and Shorter Schedules of Hepatitis E Vaccine: A Systematic Review

by Bilal Azam, Melanie Marti, Amit Goel and Rakesh Aggarwal

Vaccines 2025, 13(1), 28; https://doi.org/10.3390/vaccines13010028 - 31 Dec 2024

Viewed by 1043

Abstract

Background: Hepatitis E virus (HEV) is a leading cause of acute viral hepatitis in adults. The schedule for HEV 239, the only approved anti-HEV vaccine, consists of three doses at 0, 1, and 6 months, which is unsuitable for use in emergency [...] Read more.

Background: Hepatitis E virus (HEV) is a leading cause of acute viral hepatitis in adults. The schedule for HEV 239, the only approved anti-HEV vaccine, consists of three doses at 0, 1, and 6 months, which is unsuitable for use in emergency and outbreak situations where quick protection is desired. We, therefore, undertook a systematic review of data on immunogenicity, efficacy, and effectiveness of alternative accelerated schedules. Methods: Data sources on immunogenicity, efficacy, and effectiveness of the HEV 239 vaccine following accelerated schedules published between 22 January 2005 and February 2024 were identified from five electronic databases, and the relevant data were extracted. Results: The search identified seven relevant reports, including one phase II pre-licensure trial, three reports from the phase III licensure trial, and three post-licensure reports. In these studies, following administration of the HEV 239 vaccine in two doses at 0 and 1 month or a three-dose rapid (0, 7, and 21 days) schedule, anti-HEV antibody seroconversion rates were similar to and geometric mean concentrations of anti-HEV antibody were only slightly lower than those following the standard three-dose schedule. In individuals who were seropositive for anti-HEV antibodies at baseline, the antibody response persisted for several years irrespective of the number of vaccine doses, and in those who were seronegative at baseline, administration of two vaccine doses induced antibodies whose level remained substantially high till at least 13 months of follow-up. Administration of two doses was also associated with a high protective efficacy against HEV infection and associated disease. Conclusions: The available data indicate that two doses of HEV 239 administered one month apart confer sufficiently high antibody titers and protection for at least 13 months, a duration which should be adequate for its use as an outbreak control measure. Full article

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

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12 pages, 286 KiB

Open AccessOpinion

Epidemiology of Pertussis After the COVID-19 Pandemic: Analysis of the Factors Involved in the Resurgence of the Disease in High-, Middle-, and Low-Income Countries

by Lucia F. Bricks, Juan C. Vargas-Zambrano and Denis Macina

Vaccines 2024, 12(12), 1346; https://doi.org/10.3390/vaccines12121346 - 28 Nov 2024

Cited by 3 | Viewed by 1740

Abstract

Pertussis is a highly contagious bacterial disease of the respiratory tract that can be prevented by vaccination. Before the COVID-19 pandemic, the vaccine coverage rate for the third dose of a DPT-containing vaccine was 86%, with large disparities among countries. Since 2022, many [...] Read more.

Pertussis is a highly contagious bacterial disease of the respiratory tract that can be prevented by vaccination. Before the COVID-19 pandemic, the vaccine coverage rate for the third dose of a DPT-containing vaccine was 86%, with large disparities among countries. Since 2022, many high-income countries have reported a resurgence of pertussis, especially in the European region, but the disease has also caused outbreaks in middle- and low-income countries, despite their less extensive disease surveillance capacities. This paper aims to review the incidence rates (IRs) of pertussis in high-, middle-, and low-income countries following the COVID-19 pandemic and to discuss the most relevant factors associated with the resurgence of the disease. The epidemiology of pertussis is highly variable and is influenced not only by the type of vaccine used but also by the specific characteristics of the disease, vaccine coverage rates, vaccination schedules, and the quality of surveillance. Since the cessation of COVID-19 measures, there have been significant pertussis outbreaks that could have been partially mitigated with higher coverage rates and more comprehensive pertussis vaccination throughout life. Full article

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

16 pages, 778 KiB

Open AccessOpinion

Polio Epidemiology: Strategies and Challenges for Polio Eradication Post the COVID-19 Pandemic

by Lucia F. Bricks, Denis Macina and Juan C. Vargas-Zambrano

Vaccines 2024, 12(12), 1323; https://doi.org/10.3390/vaccines12121323 - 26 Nov 2024

Viewed by 1893

Abstract

The Global Polio Eradication Initiative (GPEI), launched in 1988, has successfully reduced wild poliovirus (WPV) cases by over 99.9%, with WPV type 2 and WPV3 declared eradicated in 2015 and 2019, respectively. However, as of 2024, WPV1 remains endemic in Afghanistan and Pakistan. [...] Read more.

The Global Polio Eradication Initiative (GPEI), launched in 1988, has successfully reduced wild poliovirus (WPV) cases by over 99.9%, with WPV type 2 and WPV3 declared eradicated in 2015 and 2019, respectively. However, as of 2024, WPV1 remains endemic in Afghanistan and Pakistan. Since 2000, outbreaks of circulating virus derived of polio vaccines (cVDPVs) have emerged in multiple regions, primary driven by low vaccine coverage rates (VCRs). The COVID-19 pandemic disrupted routine immunization, resulting in millions of unvaccinated children, and leaving many countries vulnerable to both WPV1 and cVDPVs outbreaks. This paper reviews the epidemiological landscape of poliomyelitis post the COVID-19 pandemic, and the strategies and challenges to achieve the global polio eradication. Full article

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

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29 pages, 711 KiB

Open AccessSystematic Review

Integrated Approaches for the Delivery of Maternal and Child Health Services with Childhood Immunization Programs in Low- and Middle-Income Countries: Systematic Review Update 2011–2020

by Monica P. Shah, Christopher J. Morgan, James G. Beeson, Elizabeth Peach, Jessica Davis, Barbara McPake and Aaron S. Wallace

Vaccines 2024, 12(12), 1313; https://doi.org/10.3390/vaccines12121313 - 23 Nov 2024

Viewed by 2024

Abstract

Background: The integration of maternal and child health services (MCH) with routine immunization is an important global health strategy, particularly in low- and middle-income countries (LMICs). However, evidence is lacking regarding the best practices for service integration and the effect of integration [...] Read more.

Background: The integration of maternal and child health services (MCH) with routine immunization is an important global health strategy, particularly in low- and middle-income countries (LMICs). However, evidence is lacking regarding the best practices for service integration and the effect of integration on immunization and linked health service outcomes. Methods: We searched publication databases and gray literature for articles published between 2011 and 2020 that include approaches to integrating MCH services with immunizations during the first two years of life in LMICs. Abstracts and full-text articles were screened for eligibility. For the included articles, data extraction and analysis examined the descriptive characteristics of studies, outcomes, and implementation considerations. Results: Among the 16,578 articles screened, 44 met the criteria for inclusion, representing 34 studies, of which 29 were from Africa. The commonly linked MCH services were family planning (24%), human immunodeficiency virus (HIV) diagnosis or care (21%), and malaria prevention or control (21%). Multiple integration strategies were typically used; the co-location of linked services (65%), the provision of extra services by immunization staff (41%), and/or the provision of extra information by immunization staff (41%) were the most common. In general, integration improved MCH service outcomes (76%) and was either beneficial (55%) or neutral for immunization (35%), with some examples in family planning, malaria, and HIV where integrated services were not beneficial. Important implementation considerations included the careful matching of target populations in service re-design, ensuring support from policy, logistics, and information systems, the provision of adequate training and support of staff to avoid overload, clear client communication regarding service integration, and the need to address community concerns. Conclusions: Integrating MCH services with routine immunization can expand linked services and improve immunization coverage. This study has identified key implementation considerations relevant to both childhood and adult vaccination programs. More research is needed regarding costs and client preferences. Full article

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

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