Modeling the impact of vaccination for the immunization Agenda 2030: Deaths averted due to vaccination against 14 pathogens in 194 countries from 2021 to 2030

Factors influencing COVID-19 vaccine acceptability among household heads in northern Nigeria: a community-based cross-sectional study

OBJECTIVES

COVID-19 vaccine was rolled out for the public in August 2021 in Zamfara state, Northen Nigeria. We determined the factors influencing COVID-19 vaccine acceptance.

SETTINGS

We executed a community-based analytical cross-sectional study during the first 4 months of the second phase of the COVID-19 (Oxford/AstraZeneca) mass vaccination campaign in Zamfara state.

PARTICIPANTS

We used multistage sampling to select 910 household heads.

OUTCOME MEASURES

We used a semistructured electronic questionnaire to collect data on sociodemographic characteristics, uptake and acceptance of COVID-19 vaccine between 12 October and 20 December 2021. We calculated frequencies, proportions, adjusted ORs and 95% CIs for factors influencing COVID-19 vaccine acceptance using logistic regression.

RESULTS

Our respondents had a median age of 48 years (IQR: 37-55), 78.1% (711) were men, a majority more than 30 years, and only 8.9% (81) had received COVID-19 vaccine. Of the 829 unvaccinated respondents, 10.1% (84) accepted to take the vaccine, the current week of the interview while 12.2% (101) rejected the vaccine. Individuals aged 30 years and older (adjusted OR (aOR)=2.39, 95% CI 1.16 to 4.94, p=0.018), who owned a mobile phone (aOR=25.35, 95% CI 11.23 to 57.23, p<0.001) and a television (aOR=3.72, 95% CI 1.09 to 12.69, p=0.036), with medium-high levels of trust (aOR=7.41, 95% CI 3.10 to 17.74, p<0.001), and those with a medium-high (positive) levels of attitude (aOR=1.82, 95% CI 1.06 to 3.11, p=0.029) were more likely to accept the COVID-19 vaccine. Also, those who had been vaccinated with other vaccines (aOR=2.2, 95% CI 1.09 to 4.43, p=0.027) and those previously tested for COVID-19 (aOR=2.0, 95% CI 1.10 to 3.66, p=0.023) were also more likely to accept it.

CONCLUSION

COVID-19 vaccine had a poor uptake and acceptance. Factors such as age, awareness, trust and previous vaccination experience played a significant role in COVID-19 vaccine acceptance. We recommended targeted public health campaigns, improving community engagement and building trust in community leaders, healthcare providers and public health institutions.

The contributions of T cell-mediated immunity to protection from vaccine-preventable diseases: A primer

In the face of the ever-present burden of emerging and reemerging infectious diseases, there is a growing need to comprehensively assess individual- and population-level immunity to vaccine-preventable diseases (VPDs). Many of these efforts, however, focus exclusively on antibody-mediated immunity, ignoring the role of T cells. Aimed at clinicians, public health practioners, and others who play central roles in human vaccine research but do not have formal training in immunology, we review how vaccines against infectious diseases elicit T cell responses, what types of vaccines elicit T cell responses, and how T cell responses are measured. We then use examples to demonstrate six ways that T cells contribute to protection from VPD, including directly mediating protection, enabling antibody responses, reducing disease severity, increasing cross-reactivity, improving durability, and protecting special populations. We conclude with a discussion of challenges and solutions to more widespread consideration of T cell responses in clinical vaccinology.

Sustainable financing for vaccination towards advancing universal health coverage in the WHO African region: The strategic role of national health insurance

There is a growing political interest in health reforms in Africa, and many countries are choosing national health insurance as their main financing mechanism for universal health coverage. Although vaccination is an essential health service that can influence progress toward universal health coverage, it is not often prioritized by these national health insurance systems. This paper highlights the potential gains of integrating vaccination into the package of health services that is provided through national health insurance and recommends practical policy actions that can enable countries to harness these benefits at population level.

Global challenges and solutions to achieving and sustaining measles and rubella elimination

Measles and rubella have long been recognized as priorities for disease prevention because of their devastating consequences for child health; hence, all World Health Organization (WHO) regions currently have a goal to eliminate measles and four out of six WHO regions have a goal to eliminate rubella. Significant global progress has been made in the twenty-first century, with more than 40% of countries in the world verified by a Regional Verification Commission as having eliminated measles and more than 50% of countries having sustained rubella elimination. Making further progress will require addressing fundamental gaps in health systems, a particular challenge in the current global context where many countries face multiple barriers to both sustaining and achieving measles and rubella elimination. These challenges require a strategic shift toward a holistic approach that embeds immunization at the center of primary health care at all levels, which will have broad benefits beyond preventing measles and rubella. Progress will be supported through technological innovations such as microarray patch vaccines. Whether this holistic approach will be more effective than vertical initiatives at achieving measles and rubella elimination remains to be seen. Measles is so infectious and its immediate impact so visible on individuals and health systems that any weaknesses in global or national strategy are immediately evident. The tools exist to prevent every death from measles and every case of congenital rubella syndrome. Countries and partners - at all levels - share accountability for ensuring children are protected from these entirely preventable diseases.

How mathematical modelling can inform outbreak response vaccination

Mathematical models are established tools to assist in outbreak response. They help characterise complex patterns in disease spread, simulate control options to assist public health authorities in decision-making, and longer-term operational and financial planning. In the context of vaccine-preventable diseases (VPDs), vaccines are one of the most-cost effective outbreak response interventions, with the potential to avert significant morbidity and mortality through timely delivery. Models can contribute to the design of vaccine response by investigating the importance of timeliness, identifying high-risk areas, prioritising the use of limited vaccine supply, highlighting surveillance gaps and reporting, and determining the short- and long-term benefits. In this review, we examine how models have been used to inform vaccine response for 10 VPDs, and provide additional insights into the challenges of outbreak response modelling, such as data gaps, key vaccine-specific considerations, and communication between modellers and stakeholders. We illustrate that while models are key to policy-oriented outbreak vaccine response, they can only be as good as the surveillance data that inform them.

Vaccine Strategies Against RNA Viruses: Current Advances and Future Directions

The development of vaccines against RNA viruses has undergone a rapid evolution in recent years, particularly driven by the COVID-19 pandemic. This review examines the key roles that RNA viruses, with their high mutation rates and zoonotic potential, play in fostering vaccine innovation. We also discuss both traditional and modern vaccine platforms and the impact of new technologies, such as artificial intelligence, on optimizing immunization strategies. This review evaluates various vaccine platforms, ranging from traditional approaches (inactivated and live-attenuated vaccines) to modern technologies (subunit vaccines, viral and bacterial vectors, nucleic acid vaccines such as mRNA and DNA, and phage-like particle vaccines). To illustrate these platforms' practical applications, we present case studies of vaccines developed for RNA viruses such as SARS-CoV-2, influenza, Zika, and dengue. Additionally, we assess the role of artificial intelligence in predicting viral mutations and enhancing vaccine design. The case studies underscore the successful application of RNA-based vaccines, particularly in the fight against COVID-19, which has saved millions of lives. Current clinical trials for influenza, Zika, and dengue vaccines continue to show promise, highlighting the growing efficacy and adaptability of these platforms. Furthermore, artificial intelligence is driving improvements in vaccine candidate optimization and providing predictive models for viral evolution, enhancing our ability to respond to future outbreaks. Advances in vaccine technology, such as the success of mRNA vaccines against SARS-CoV-2, highlight the potential of nucleic acid platforms in combating RNA viruses. Ongoing trials for influenza, Zika, and dengue demonstrate platform adaptability, while artificial intelligence enhances vaccine design by predicting viral mutations. Integrating these innovations with the One Health approach, which unites human, animal, and environmental health, is essential for strengthening global preparedness against future RNA virus threats.

Assessment of the Communicable Disease Status of Children in Türkiye: A Community-Based Cross-Sectional Study

AIM

Assessment of children's communicable disease status is effective in preventing child morbidity. This study aims to evaluate the infectious disease status of children aged 0-14 in Türkiye.

METHODS

The research is a cross-sectional study conducted using the microdataset of the "Türkiye Health Survey 2022" obtained from the Turkish Statistical Institute. Seven thousand nineteen individuals aged 0-14 were included in the analysis. Data on communicable diseases of children aged 0-14 years in the 6-month period before the survey date was obtained by asking the household head.

RESULTS

In our research, the data of 7019 individuals aged 0-14 was evaluated. It was determined that 2.2% of children had a vaccine-preventable infectious disease in the last 6 months. It was observed that the frequency of upper respiratory tract infection, lower respiratory tract infection, urinary tract infection, and diarrhea in children was higher in the 0-6 age group than in the 7-14 age group. Urinary tract infections were more common in girls, whereas respiratory tract infections, communicable diseases, and diarrhea were more common in boys.

CONCLUSION

It was determined that diarrhea and upper respiratory tract infections occur in approximately one out of every three children in the 0-6 age group.

Strengthening Capacity for Tailored Immunization Programs Using Adult Learning Principles: A Case Study from Nigeria

Introduction: Nigeria has the highest number of children who have not received any vaccines in Africa. The training-of-trainers (TOT) model used to train program managers (PMs) and health care workers (HCWs) is ineffective for adult learning and limits immunization programs' success. We incorporated adult learning principles (ALPs) in designing and delivering TOT for immunization PMs and HCWs to use data to engage communities for tailored immunization strategies.Methods: Our study was implemented in 3 local government areas (LGAs) of the Federal Capital Territory, Nigeria. A training curriculum was developed, integrating ALPs and technical and operational content based on best practices in delivering immunization training and the training needs assessment findings. State PMs (n=10), LGA PMs (n=30), and HCWs (n=42) were trained on the human-centered design for tailoring immunization programs (HCD-TIP) approaches using ALPs. We used interviews and surveys with purposively and conveniently sampled PMs and HCWs, respectively, and observations to assess participants' satisfaction, knowledge and competence, behavior changes, and results. The interviews were analyzed thematically, and surveys were statistically.Results: There was a high level of satisfaction with the training among LGA PMs (100%), state PMs (91%), and HCWs (85%), with significant knowledge and competence improvements post-training (P<.001). The trained participants conducted 2 HCD sessions with 24 undervaccinated communities and co-designed 24 prototype solutions for testing. Results showed increased coverage of the pentavalent vaccine first dose (54%) and third dose (188%) across 12 participating communities. Improved community colaboration, communication skills, and data-driven approaches were the most cited behavior changes in practice.Conclusion: The application of ALPs in training, use of HCD-TIP approaches and tools, and supportive supervision enhanced PMs' and HCWs' capacity for tailored interventions. Countries should consider adopting a holistic approach that focuses on using these approaches in immunization programs to strengthen the health system for equitable vaccine coverage.

Spatial targeting and integration across vaccination, vitamin A and deworming programs throughout India 2019-21

BACKGROUND

Currently, most large-scale public health programs, such as immunization or anti-parasitic deworming, work in relative isolation. Integrating efforts across programs could potentially improve their efficiency, but identifying populations that could benefit from multiple programs has been an operational challenge.

METHODS

We analyzed a nationally representative survey conducted in India between 2019 and 2021 to assess and map coverage of seven vaccines [Bacillus Calmette-Guérin (BCG), hepatitis B, polio, diphtheria-tetanus-pertussis (DTP), haemophilus influenza type b (Hib), rotavirus and measles-containing vaccine (MCV)], plus Vitamin A supplementation and anti-parasitic deworming treatment among 86 761 children aged 1-3 years old.

RESULTS

National coverage varied widely by program, from 42% (rotavirus) to 95% (BCG). There was high correlation between district-level coverage estimates (r ≥ 0.7) and extensive spatial overlap in low-coverage populations. In simulated implementation strategies, we show that an integrated strategy that targets full immunization coverage for four core vaccines (BCG, polio, DTP, MCV) would achieve similar coverage to an optimal (but unrealistic) implementation strategy and far better coverage than multiple efforts focused on individual vaccines. Targeting the most under-vaccinated districts within states based on spatial clustering or coverage thresholds led to further improvements in full coverage per child targeted. Integration of anti-parasitic deworming or rotavirus vaccination into a core vaccine delivery mission could nearly double their coverage (from ∼45% to ∼85%).

CONCLUSIONS

Integrated delivery and geographic targeting across core vaccines could accelerate India's progress toward full immunization coverage. An integrated platform could greatly expand coverage of non-core vaccines and other child health interventions.

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

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.

Estimating the impact of vaccination: lessons learned in the first phase of the Vaccine Impact Modelling Consortium

Estimates of the global health impact of immunisation are important for quantifying historical benefits as well as planning future investments and strategy. The Vaccine Impact Modelling Consortium (VIMC) was established in 2016 to provide reliable estimates of the health impact of immunisation. In this article we examine the consortium in its first five-year phase. We detail how vaccine impact was defined and the methods used to estimate it as well as the technical infrastructure required to underpin robust reproducibility of the outputs. We highlight some of the applications of estimates to date, how these were communicated and what their effect were. Finally, we explore some of the lessons learnt and remaining challenges for estimating the impact of vaccines and forming effective modelling consortia then discuss how this may be addressed in the second phase of VIMC. Modelled estimates are not a replacement for surveillance; however, they can examine theoretical counterfactuals and highlight data gaps to complement other activities. VIMC has implemented strategies to produce robust, standardised estimates of immunisation impact. But through the first phase of the consortium, critical lessons have been learnt both on the technical infrastructure and the effective engagement with modellers and stakeholders. To be successful, a productive dialogue with estimate consumers, producers and stakeholders needs to be underpinned by a rigorous and transparent analytical framework as well as an approach for building expertise in the short and long term.

Global Status Report for the Verification of Measles and Rubella Elimination, 2022

Since the World Health Assembly (WHA) in 2012 endorsed the Global Vaccine Action Plan (GVAP), which included regional measles and rubella elimination goals by 2020, global progress towards verification of measles and rubella elimination has been incremental. Even though the 2020 elimination goals were not achieved, commitment towards achieving measles and rubella elimination has been firmly established in the Immunization Agenda 2030 (IA2030) and the Measles and Rubella Strategic Framework (MRSF) 2021-2030. In 2023, the six Regional Verification Commissions for measles and rubella elimination (RVCs) reviewed data as of 31 December 2022 and confirmed that 82 (42%) Member States have been verified for measles elimination, and 98 (51%) Member States have been verified for rubella elimination. The six RVCs are composed of independent public health and immunization experts who are well-placed to support accelerating measles and rubella elimination. RVCs should be leveraged not only to review elimination documents but also to advocate for and champion public health programming that supports measles and rubella activities. The verification of elimination process is one of many tools that should be deployed to reinforce and accelerate efforts towards achieving a world free of measles and rubella.

What's going on with measles?

Measles is a highly transmissible systemic viral infection associated with substantial mortality primarily due to secondary infections. Measles induces lifelong immunity to reinfection but loss of immunity to other pathogens. An attenuated live virus vaccine is highly effective, but lapses in delivery have resulted in increasing cases worldwide. Although the primary cause of failure to control measles is failure to vaccinate, waning vaccine-induced immunity and the possible emergence of more virulent virus strains may also contribute.

A Structured Narrative Literature Review of the Broader Value of Adult Immunisation Programmes

Vaccine-preventable diseases continue to generate a substantial burden on health, healthcare systems, and societies, which is projected to increase with population ageing. There is a need to better understand the full value of adult immunisation programmes corresponding to the broader value of vaccine frameworks that are recommended for evidence-based decision-making. This review aims to summarise and map evidence for the value of selected adult immunisation programmes (seasonal influenza, pneumococcal disease, RSV, and HZ) in ten diverse countries. We conducted a structured literature review of evidence published from 2017 to 2023. An existing framework was used to structure the assessment, developing matrices demonstrating the elements of value evidenced for each vaccine and country of focus. Our analysis showed substantial evidence base on the value of adult immunisation programmes, but the availability of evidence varied by value element and by vaccine. The impact on the quality of life of the vaccinated individual was the most evidenced value element. Mortality benefits for vaccinated individuals and cost-offsets to healthcare systems were also well-evidenced. The availability of evidence for 'broader' societal value elements (such as transmission value, carer productivity and impact on social equity, and antimicrobial resistance prevention) varied. No evidence was identified relating to the broader value elements of macroeconomic effects, value to other interventions, or effects on the quality of life of caregivers. Robust evidence exists to show that adult immunisation programmes generate substantial value for population health and health systems, yet some elements of broader value remain underrepresented in the academic literature. Without such evidence, the full value of immunisation programmes is underestimated, risking suboptimal policy decisions.

Integrating Digital Health Solutions with Immunization Strategies: Improving Immunization Coverage and Monitoring in the Post-COVID-19 Era

The COVID-19 pandemic underscored the critical importance of vaccination to global health security and highlighted the potential of digital health solutions to improve immunization strategies. This article explores integrating digital health technologies with immunization programs to improve coverage, monitoring, and public health outcomes. It examines the current landscape of digital tools used in immunization initiatives, such as mobile health apps, electronic health records, and data analytics platforms. Case studies from different regions demonstrate the effectiveness of these technologies in addressing challenges such as vaccine hesitancy, logistics, and real-time monitoring of vaccine distribution and adverse events. The paper also examines ethical considerations, data privacy issues, and the need for a robust digital infrastructure to support these innovations. By analyzing the successes and limitations of digital health interventions in immunization campaigns during and after the COVID-19 pandemic, we provide recommendations for future integration strategies to ensure resilient and responsive immunization systems. This research aims to guide policymakers, health professionals, and technologists in leveraging digital health to strengthen immunization efforts and prepare for future public health emergencies.

An Interrupted Time Series Analysis of the Impact of the COVID-19 Pandemic on Routine Vaccination Uptake in Kenya

A strategic priority of the World Health Organization's Immunization Agenda 2030 is to increase vaccination coverage and equity through reaching "zero-dose" children. Through an ecological study, we sought to quantify the impact of the COVID-19 pandemic on the coverage of the pentavalent and the measles/rubella vaccines in Kenya, without implying causality. The monthly number of doses from January 2017 to August 2022 were obtained from the Kenya Health Information System for the pentavalent and the measles/rubella vaccines. Immediate (step) and long-term (ramp) changes following interruptions occurring during the period from March 2020 to December 2020 were assessed through an interrupted time series analysis using an autoregressive integrated moving average (ARIMA) model, accounting for seasonality. In December 2020, there was an immediate decrease of 8337, 12,212, and 20,848 in the number of doses for the first, second, and third dose of the pentavalent vaccine, respectively (statistically significant for the third dose only). This corresponded to a percentage relative difference of -21.6, -20.1, and -24.5, respectively, for three doses of pentavalent vaccines, while for measles/rubella vaccine it was -27.3 and -33.6, respectively, for the first and second dose. COVID-19 resulted in interruptions affecting routine immunization, but recovery occurred within four months.

Accelerating Global Measles and Rubella Eradication-Saving Millions of Lives, Preventing Disability, and Averting the Next Pandemic

No vaccine has been more effective in reducing disease burden, especially in preventing child deaths, than measles-containing vaccine. The return on investment makes measles-containing vaccine one of the most cost-effective public health measures available. Exhaustive reviews of biological, technical, economic and programmatic evidence have concluded that measles can and should be eradicated, and by including rubella antigen in measles-containing vaccine, congenital rubella syndrome will also be eradicated. All World Health Organisation Regions have pledged to achieve measles elimination. Unfortunately, not all countries and global partners have demonstrated an appropriate commitment to these laudable public health goals, and the negative impact of the COVID-19 pandemic on coverage rates has been profound. Unsurprisingly, large disruptive outbreaks are already occurring in many countries with a global epidemic curve ominously similar to that of 2018/2019 emerging. The Immunization Agenda 2030 will fail dismally unless measles and rubella eradication efforts are accelerated. Over half of all member states have been verified to have eliminated rubella and endemic rubella transmission has not been re-established in any country to date. In 2023, 84 countries and areas were verified to have sustained elimination of measles. However, without a global target, this success will be difficult to sustain. Now is the time for a global eradication goal and commitment by the World Health Assembly. Having a galvanising goal, with a shared call for action, will demand adequate resourcing from every country government and global partners. Greater coordination across countries and regions will be necessary. Measles, rubella and congenital rubella syndrome eradication should not remain just a technically feasible possibility but rather be completed to ensure that future generations of children do not live under the shadow of preventable childhood death and lifelong disability.

Struggling to resume childhood vaccination during war in Myanmar: evaluation of a pilot program

BACKGROUND

After the military coup in Myanmar in February 2021, the health system began to disintegrate when staff who called for the restoration of the democratic government resigned and fled to states controlled by ethnic minorities. The military retaliated by blocking the shipment of humanitarian aid, including vaccines, and attacked the ethnic states. After two years without vaccines for their children, parents urged a nurse-led civil society organization in an ethnic state to find a way to resume vaccination. The nurses developed a vaccination program, which we evaluated.

METHODS

A retrospective cohort study and participatory evaluation were conducted. We interviewed the healthcare workers about vaccine acquisition, transportation, and administration and assessed compliance with WHO-recommended practices. We analyzed the participating children's characteristics. We calculated the proportion of children vaccinated before and after the program. We calculated the probability children would become up-to-date after the program using inverse survival.

RESULTS

Since United Nations agencies could not assist, private donations were raised to purchase, smuggle into Myanmar, and administer five vaccines. Cold chain standards were maintained. Compliance with other WHO-recommended vaccination practices was 74%. Of the 184 participating children, 145 (79%, median age five months [IQR 6.5]) were previously unvaccinated, and 71 (41%) were internally displaced. During five monthly sessions, the probability that age-eligible zero-dose children would receive the recommended number of doses of MMR was 92% (95% confidence interval [CI] 83-100%), Penta 87% (95% CI 80%-94%); BCG 76% (95% CI 69%-83%); and OPV 68% (95% CI 59%-78%). Migration of internally displaced children and stockouts of vaccines were the primary factors responsible for decreased coverage.

CONCLUSIONS

This is the first study to describe the situation, barriers, and outcomes of a childhood vaccination program in one of the many conflict-affected states since the coup in Myanmar. Even though the proportion of previously unvaccinated children was large, the program was successful. While the target population was necessarily small, the program's success led to a donor-funded expansion to 2,000 children. Without renewed efforts, the proportion of unvaccinated children in other parts of Myanmar will approach 100%.

Facilitating the development of urgently required combination vaccines

The essence of a vaccine lies in its ability to elicit a set of immune responses specifically directed at a particular pathogen. Accordingly, vaccines were historically designed, developed, registered, recommended, procured, and administered as monopathogen formulations. Nonetheless, the control and elimination of an astonishing number of diseases was realised only after several once-separate vaccines were provided as combinations. Unfortunately, the current superabundance of recommended and pipeline vaccines is now at odds with the number of acceptable vaccine administrations and feasible health-care visits for vaccine recipients and health-care providers. Yet, few new combinations are in development because, in addition to the scientific and manufacturing hurdles intrinsic to coformulation, developers face a gauntlet of regulatory, policy, and commercialisation obstacles in a milieu still largely designed for monopathogen vaccines. We argue here that national policy makers and public health agencies should prospectively identify and advocate for the development of new multipathogen combination vaccines, and suggest ways to accelerate the regulatory pathways to licensure of combinations and other concrete, innovative steps to mitigate current obstacles.

Report from the World Health Organization's immunization and vaccines-related implementation research advisory committee (IVIR-AC) meeting, virtual gathering, 26 February-1 March 2024

The Immunization and Vaccine-related Implementation Research Advisory Committee (IVIR-AC) is the World Health Organization's key standing advisory body to conduct an independent review of research, particularly of transmission and economic modeling analyses that estimate the impact and value of vaccines. From 26th February-1st March 2024, at its first of two semi-annual meetings, IVIR-AC provided feedback and recommendations across four sessions; this report summarizes the proceedings and recommendations from that meeting. Session topics included modeling of the impact and cost-effectiveness of the R21/Matrix-M malaria vaccine, meta-analysis of economic evaluations of vaccines, a global analysis estimating the impact of vaccination over the last 50 years, and modeling the impact of different RTS,S malaria vaccine dose schedules in seasonal settings.

Electronic Immunization Registry in Rwanda: Qualitative Study of Health Worker Experiences

BACKGROUND

Monitoring childhood immunization programs is essential for health systems. Despite the introduction of an electronic immunization registry called e-Tracker in Rwanda, challenges such as lacking population denominators persist, leading to implausible reports of coverage rates of more than 100%.

OBJECTIVE

This study aimed to assess the extent to which the immunization e-Tracker responds to stakeholders' needs and identify key areas for improvement.

METHODS

In-depth interviews were conducted with all levels of e-Tracker users including immunization nurses, data managers, and supervisors from health facilities in 5 districts of Rwanda. We used an interview guide based on the constructs of the Human, Organization, and Technology-Fit (HOT-Fit) framework, and we analyzed and summarized our findings using the framework.

RESULTS

Immunization nurses reported using the e-Tracker as a secondary data entry tool in addition to paper-based forms, which resulted in considerable dissatisfaction among nurses. While users acknowledged the potential of a digital tool compared to paper-based systems, they also reported the need for improvement of functionalities to support their work, such as digital client appointment lists, lists of defaulters, search and register functions, automated monthly reports, and linkages to birth notifications and the national identity system.

CONCLUSIONS

Reducing dual documentation for users can improve e-Tracker use and user satisfaction. Our findings can help identify additional digital health interventions to support and strengthen the health information system for the immunization program.

Contribution of vaccination to improved survival and health: modelling 50 years of the Expanded Programme on Immunization

BACKGROUND

WHO, as requested by its member states, launched the Expanded Programme on Immunization (EPI) in 1974 to make life-saving vaccines available to all globally. To mark the 50-year anniversary of EPI, we sought to quantify the public health impact of vaccination globally since the programme's inception.

METHODS

In this modelling study, we used a suite of mathematical and statistical models to estimate the global and regional public health impact of 50 years of vaccination against 14 pathogens in EPI. For the modelled pathogens, we considered coverage of all routine and supplementary vaccines delivered since 1974 and estimated the mortality and morbidity averted for each age cohort relative to a hypothetical scenario of no historical vaccination. We then used these modelled outcomes to estimate the contribution of vaccination to globally declining infant and child mortality rates over this period.

FINDINGS

Since 1974, vaccination has averted 154 million deaths, including 146 million among children younger than 5 years of whom 101 million were infants younger than 1 year. For every death averted, 66 years of full health were gained on average, translating to 10·2 billion years of full health gained. We estimate that vaccination has accounted for 40% of the observed decline in global infant mortality, 52% in the African region. In 2024, a child younger than 10 years is 40% more likely to survive to their next birthday relative to a hypothetical scenario of no historical vaccination. Increased survival probability is observed even well into late adulthood.

INTERPRETATION

Since 1974 substantial gains in childhood survival have occurred in every global region. We estimate that EPI has provided the single greatest contribution to improved infant survival over the past 50 years. In the context of strengthening primary health care, our results show that equitable universal access to immunisation remains crucial to sustain health gains and continue to save future lives from preventable infectious mortality.

FUNDING

WHO.

Estimating the health effects of COVID-19-related immunisation disruptions in 112 countries during 2020-30: a modelling study

BACKGROUND

There have been declines in global immunisation coverage due to the COVID-19 pandemic. Recovery has begun but is geographically variable. This disruption has led to under-immunised cohorts and interrupted progress in reducing vaccine-preventable disease burden. There have, so far, been few studies of the effects of coverage disruption on vaccine effects. We aimed to quantify the effects of vaccine-coverage disruption on routine and campaign immunisation services, identify cohorts and regions that could particularly benefit from catch-up activities, and establish if losses in effect could be recovered.

METHODS

For this modelling study, we used modelling groups from the Vaccine Impact Modelling Consortium from 112 low-income and middle-income countries to estimate vaccine effect for 14 pathogens. One set of modelling estimates used vaccine-coverage data from 1937 to 2021 for a subset of vaccine-preventable, outbreak-prone or priority diseases (ie, measles, rubella, hepatitis B, human papillomavirus [HPV], meningitis A, and yellow fever) to examine mitigation measures, hereafter referred to as recovery runs. The second set of estimates were conducted with vaccine-coverage data from 1937 to 2020, used to calculate effect ratios (ie, the burden averted per dose) for all 14 included vaccines and diseases, hereafter referred to as full runs. Both runs were modelled from Jan 1, 2000, to Dec 31, 2100. Countries were included if they were in the Gavi, the Vaccine Alliance portfolio; had notable burden; or had notable strategic vaccination activities. These countries represented the majority of global vaccine-preventable disease burden. Vaccine coverage was informed by historical estimates from WHO-UNICEF Estimates of National Immunization Coverage and the immunisation repository of WHO for data up to and including 2021. From 2022 onwards, we estimated coverage on the basis of guidance about campaign frequency, non-linear assumptions about the recovery of routine immunisation to pre-disruption magnitude, and 2030 endpoints informed by the WHO Immunization Agenda 2030 aims and expert consultation. We examined three main scenarios: no disruption, baseline recovery, and baseline recovery and catch-up.

FINDINGS

We estimated that disruption to measles, rubella, HPV, hepatitis B, meningitis A, and yellow fever vaccination could lead to 49 119 additional deaths (95% credible interval [CrI] 17 248-134 941) during calendar years 2020-30, largely due to measles. For years of vaccination 2020-30 for all 14 pathogens, disruption could lead to a 2·66% (95% CrI 2·52-2·81) reduction in long-term effect from 37 378 194 deaths averted (34 450 249-40 241 202) to 36 410 559 deaths averted (33 515 397-39 241 799). We estimated that catch-up activities could avert 78·9% (40·4-151·4) of excess deaths between calendar years 2023 and 2030 (ie, 18 900 [7037-60 223] of 25 356 [9859-75 073]).

INTERPRETATION

Our results highlight the importance of the timing of catch-up activities, considering estimated burden to improve vaccine coverage in affected cohorts. We estimated that mitigation measures for measles and yellow fever were particularly effective at reducing excess burden in the short term. Additionally, the high long-term effect of HPV vaccine as an important cervical-cancer prevention tool warrants continued immunisation efforts after disruption.

FUNDING

The Vaccine Impact Modelling Consortium, funded by Gavi, the Vaccine Alliance and the Bill & Melinda Gates Foundation.

TRANSLATIONS

For the Arabic, Chinese, French, Portguese and Spanish translations of the abstract see Supplementary Materials section.

Report from the World Health Organization's immunization and vaccines related implementation research advisory committee (IVIR-AC) meeting, Geneva, 11-13 September 2023

Evaluating vaccine-related research is critical to maximize the potential of vaccination programmes. The WHO Immunization and Vaccine-related Implementation Research Advisory Committee (IVIR-AC) provides an independent review of research that estimates the performance, impact and value of vaccines, with a particular focus on transmission and economic modelling. On 11-13 September 2023, IVIR-AC was convened for a bi-annual meeting where the committee reviewed research and presentations across eight different sessions. This report summarizes the background information, proceedings and recommendations from that meeting. Sessions ranged in topic from timing of measles supplementary immunization activities, analyses of conditions necessary to meet measles elimination in the South-East Asia region, translating modelled evidence into policy, a risk-benefit analysis of dengue vaccine, COVID-19 scenario modelling in the African region, therapeutic vaccination against human papilloma virus, the Vaccine Impact Modelling Consortium, and the Immunization Agenda 2030 vaccine impact estimates.

Informal health sector and routine immunization: making the case for harnessing the potentials of patent medicine vendors for the big catch-up to reduce zero-dose children in sub-Saharan Africa

The COVID-19 pandemic caused a surge in the number of unimmunized and under-immunized children in Africa. The majority of unimmunized (or zero-dose) children live in hard-to-reach rural areas, urban slums, and communities affected by conflict where health facilities are usually unavailable or difficult to access. In these settings, people mostly rely on the informal health sector for essential health services. Therefore, to reduce zero-dose children, it is critical to expand immunization services beyond health facilities to the informal health sector to meet the immunization needs of children in underserved places. In this perspective article, we propose a framework for the expansion of immunization services through the informal health sector as one of the pillars for the big catch-up plan to improve coverage and equity. In African countries like Nigeria, Ethiopia, Tanzania, and the Democratic Republic of Congo, patent medicine vendors serve as an important informal health sector provider group, and thus, they can be engaged to provide immunization services. A hub-and-spoke model can be used to integrate patent medicine vendors into the immunization system. A hub-and-spoke model is a framework for organization design where services that are provided by a central facility (hub) are complimented by secondary sites (spokes) to optimize access to care. Systems thinking approach should guide the design, implementation, and evaluation of this model.

A Practical Guide to Full Value of Vaccine Assessments

Articulating the wide range of health, social and economic benefits that vaccines offer may help to overcome obstacles in the vaccine development pipeline. A framework to guide the assessment and communication of the value of a vaccine-the Full Value of Vaccine Assessment (FVVA)-has been developed by the WHO. The FVVA framework offers a holistic assessment of the value of vaccines, providing a synthesis of evidence to inform the public health need of a vaccine, describing the supply and demand aspects, its market and its impact from a health, financial and economic perspective. This paper provides a practical guide to how FVVAs are developed and used to support investment in vaccines, ultimately leading to sustained implementation in countries. The FVVA includes a range of elements that can be broadly categorised as synthesis, vaccine development narrative and defining vaccine impact and value. Depending on the features of the disease/vaccine in question, different elements may be emphasised; however, a standardised set of elements is recommended for each FVVA. The FVVA should be developed by an expert group who represent a range of stakeholders, perspectives and geographies and ensure a fair, coherent and evidence-based assessment of vaccine value.

Assessing a Digital Scorecard on Global Immunization Progress: Stakeholder Views and Implications for Enhancing Performance and Accountability

Global health agencies and regional and national stakeholders collaborated to develop the Immunization Agenda 2030 Scorecard, a digital data visualization platform displaying global, regional, and country-level immunization progress. The scorecard serves to focus attention and enable strategic actions around the measures visualized. To assess the scorecard's usability, appropriateness, and context for use, we interviewed 15 immunization officers working across five global regions. To further understand the implementation context, we also reviewed the characteristics of 15 public platforms visualizing population health data. We integrated thematic findings across both methods. Many platforms highlight service gaps and enable comparisons between geographies to foster political pressure for service improvements. We observed heterogeneity regarding the platforms' focus areas and participants' leading concerns, which were management capacity and resourcing. Furthermore, one-third of platforms were out of date. Results yielded recommendations for the scorecard, which participants felt was well suited to focus the attention of decision makers on key immunization data. A simpler design coupled with implementation strategies that more actively engage policymakers would better align the scorecard with other public platforms engaging intended users. For population health platforms to serve as effective accountability mechanisms, studying implementation determinants, including usability testing, is vital to meet stakeholder needs.

Assessing Vaccination Delivery Strategies for Zero-Dose and Under-Immunized Children in the Fragile Context of Somalia

Somalia is one of 20 countries in the world with the highest numbers of zero-dose children. This study aims to identify who and where zero-dose and under-vaccinated children are and what the existing vaccine delivery strategies to reach zero-dose children in Somalia are. This qualitative study was conducted in three geographically diverse regions of Somalia (rural/remote, nomadic/pastoralists, IDPs, and urban poor population), with government officials and NGO staff (n = 17), and with vaccinators and community members (n = 52). The data were analyzed using the GAVI Vaccine Alliance IRMMA framework. Nomadic populations, internally displaced persons, and populations living in remote and Al-shabaab-controlled areas are three vulnerable and neglected populations with a high proportion of zero-dose children. Despite the contextual heterogeneity of these population groups, the lack of targeted, population-specific strategies and meaningful engagement of local communities in the planning and implementation of immunization services is problematic in effectively reaching zero-dose children. This is, to our knowledge, the first study that examines vaccination strategies for zero-dose and under-vaccinated populations in the fragile context of Somalia. Evidence on populations at risk of vaccine-preventable diseases and barriers to vital vaccination services remain critical and urgent, especially in a country like Somalia with complex health system challenges.