Who is (not) vaccinated? A proposal for a comprehensive immunization information system.

The role of immunization in public health is crucial, offering widespread protection against infectious diseases and underpinning societal well-being. However, achieving optimal vaccination coverage is impeded by vaccine hesitancy, a significant challenge that necessitates comprehensive strategies to understand and mitigate its effects. We propose the integration of Population Health Management principles with Immunization Information Systems (IISs) to address vaccine hesitancy more effectively. Our approach leverages systematic health determinants analysis to identify at-risk populations and tailor interventions, thereby promoting vaccination coverage and public health responses. We call for the development of an enhanced version of the Italian National Vaccination Registry, which aims to facilitate real-time tracking of individuals' vaccination status while improving data accuracy and interoperability among healthcare systems. This registry is designed to overcome current barriers by ensuring robust data protection, addressing cultural and organizational challenges, and integrating behavioral insights to foster informed public health campaigns. Our proposal aligns with the Italian National Vaccination Prevention Plan 2023-2025 and emphasizes proactive, evidence-based strategies to increase vaccination uptake and contrast the spread of vaccine-preventable diseases. The ultimate goal is to establish a data-driven, ethically sound framework that enhances public health outcomes and addresses the complexities of vaccine hesitancy within the Italian context and beyond.

Impact of twelve immunization-preventable infectious diseases on population health using disability-adjusted life years (DALYs) in Spain.

BACKGROUND: The objective of this study is to estimate the burden of selected immunization-preventable infectious diseases in Spain using the Burden of Communicable Diseases in Europe (BCoDE) methodology, as well as focusing on the national immunization programme and potential new inclusions. METHODS: The BCoDE methodology relies on an incidence and pathogen-based approach to calculate disease burden via disability-adjusted life year (DALY) estimates. It considers short and long-term sequelae associated to an infection via outcome trees. The BCoDE toolkit was used to populate those trees with Spanish-specific incidence estimates, and de novo outcome trees were developed for four infections (herpes zoster, rotavirus, respiratory syncytial virus [RSV], and varicella) not covered by the toolkit. Age/sex specific incidences were estimated based on data from the Spanish Network of Epidemiological Surveillance; hospitalisation and mortality rates were collected from the Minimum Basic Data Set. A literature review was performed to design the de novo models and obtain the rest of the parameters. The methodology, assumptions, data inputs and results were validated by a group of experts in epidemiology and disease modelling, immunization and public health policy. RESULTS: The total burden of disease amounted to 163.54 annual DALYs/100,000 population. Among the selected twelve diseases, respiratory infections represented around 90% of the total burden. Influenza exhibited the highest burden, with 110.00 DALYs/100,000 population, followed by invasive pneumococcal disease and RSV, with 25.20 and 10.57 DALYs/100,000 population, respectively. Herpes zoster, invasive meningococcal disease, invasive Haemophilus influenza infection and hepatitis B virus infection ranked lower with fewer than 10 DALYs/100,000 population each, while the rest of the infections had a limited burden (< 1 DALY/100,000 population). A higher burden of disease was observed in the elderly (≥ 60 years) and children < 5 years, with influenza being the main cause. In infants < 1 year, RSV represented the greatest burden. CONCLUSIONS: Aligned with the BCoDE study, the results of this analysis show a persisting high burden of immunization-preventable respiratory infections in Spain and, for the first time, highlight a high number of DALYs due to RSV. These estimates provide a basis to guide prevention strategies and make public health decisions to prioritise interventions and allocate healthcare resources in Spain.

Possible counter-intuitive impact of local vaccine mandates for vaccine-preventable infectious diseases.

We modeled the impact of local vaccine mandates on the spread of vaccine-preventable infectious diseases, which in the absence of vaccines will mainly affect children. Examples of such diseases are measles, rubella, mumps, and pertussis. To model the spread of the pathogen, we used a stochastic SIR (susceptible, infectious, recovered) model with two levels of mixing in a closed population, often referred to as the household model. In this model, individuals make local contacts within a specific small subgroup of the population (e.g., within a household or a school class), while they also make global contacts with random people in the population at a much lower rate than the rate of local contacts. We considered what would happen if schools were given freedom to impose vaccine mandates on all of their pupils, except for the pupils that were exempt from vaccination because of medical reasons. We investigated first how such a mandate affected the probability of an outbreak of a disease. Furthermore, we focused on the probability that a pupil that was medically exempt from vaccination, would get infected during an outbreak. We showed that if the population vaccine coverage was close to the herd-immunity level, then both probabilities may increase if local vaccine mandates were implemented. This was caused by unvaccinated pupils possibly being moved to schools without mandates.

Adult vaccination coverage in the United States: A database analysis and literature review of improvement strategies.

Despite vaccines being instrumental in reducing vaccine-preventable disease, adult vaccination rates in the United States (US) are below optimal levels. To better understand factors affecting vaccination rates, we analyzed trends in adult vaccination coverage using data from the Behavioral Risk Factor Surveillance System (BRFSS) and conducted a targeted literature review (TLR) on interventions to improve adult vaccination rates in the US. Both the BRFSS analysis and the TLR focused on influenza; pneumococcal disease; tetanus and diphtheria or tetanus, diphtheria, and acellular pertussis; herpes zoster; and human papillomavirus vaccination for US adults aged 18-64 years. The TLR additionally included hepatitis A and hepatitis B vaccination. Vaccination coverage rates (VCRs) and changes in VCRs were calculated using the 2011-2019 BRFSS survey data. For the TLR, the MEDLINE and MEDLINE In-Process databases were searched for articles on vaccination interventions published between January 2015 and June 2021. The BRFSS analysis showed that changes in VCRs were generally modest and positive for most states over the study period. The TLR included 32 articles that met the eligibility criteria; intervention strategies that improved adult vaccination outcomes incorporated an educational component, vaccination reminders or reinforcement at the point of care, or authorized non-clinician members of the healthcare team to vaccinate. Furthermore, interventions combining more than one approach appeared to enhance effectiveness. The strategies identified in this TLR will be valuable for policymakers and stakeholders to inform the development and implementation of evidence-based policies and practices to improve adult vaccination coverage.

Addressing the re-emergence and resurgence of vaccine-preventable diseases in Africa: A health equity perspective.

Vaccination is one of the greatest public health achievements of the 20th century, with a tremendous impact in the prevention and control of diseases. However, the recent reemergence of vaccine-preventable diseases calls for a need to evaluate current vaccination practices and disparities in vaccination between high-income countries and low-and-middle-income countries. There are massive deficits in vaccine availability and coverage in resource-constrained settings. Therefore, this perspective seeks to highlight the reemergence of vaccine-preventable diseases in Africa within the lens of health equity and offer recommendations on how the continent should be prepared to deal with the myriad of its health systems challenges. Among the notable factors contributing to the reemergence, stand health inequities affecting vaccine availability and the dynamic vaccine hesitancy. Strengthening health systems and addressing health inequities could prove useful in halting the reemergence of vaccine-preventable diseases.

Migration from Epi Info to District Health Information Software 2 for Vaccine-Preventable Disease Surveillance - World Health Organization African Region, 2019-2023.

High-quality vaccine-preventable disease (VPD) surveillance data are critical for timely outbreak detection and response. In 2019, the World Health Organization (WHO) African Regional Office (AFRO) began transitioning from Epi Info, a free, CDC-developed statistical software package with limited capability to integrate with other information systems, affecting reporting timeliness and data use, to District Health Information Software 2 (DHIS2). DHIS2 is a free and open-source software platform for electronic aggregate Integrated Disease Surveillance and Response (IDSR) and case-based surveillance reporting. A national-level reporting system, which provided countries with the option to adopt this new system, was introduced. Regionally, the Epi Info database will be replaced with a DHIS2 regional data platform. This report describes the phased implementation from 2019 to the present. Phase one (2019-2021) involved developing IDSR aggregate and case-based surveillance packages, including pilots in the countries of Mali, Rwanda, and Togo. Phase two (2022) expanded national-level implementation to 27 countries and established the WHO AFRO DHIS2 regional data platform. Phase three (from 2023 to the present) activities have been building local capacity and support for country reporting to the regional platform. By February 2024, eight of 47 AFRO countries had adopted both the aggregate IDSR and case-based surveillance packages, and two had successfully transferred VPD surveillance data to the AFRO regional platform. Challenges included limited human and financial resources, the need to establish data-sharing and governance agreements, technical support for data transfer, and building local capacity to report to the regional platform. Despite these challenges, the transition to DHIS2 will support efficient data transmission to strengthen VPD detection, response, and public health emergencies through improved system integration and interoperability.

Global burden and economic impact of vaccine-preventable cancer mortality.

BACKGROUND: Infections are responsible for approximately 13% of cancer cases worldwide and many of these infections can be prevented by vaccination. Human papillomavirus (HPV) and hepatitis B virus (HBV) are among the most common infections that cause cancer deaths globally, despite effective prophylactic vaccines being available. This analysis aims to estimate the global burden and economic impact of vaccine-preventable cancer mortality across World Health Organization (WHO) regions. METHODS: The number of deaths and years of life lost (YLL) due to five different vaccine-preventable cancer forms (oral cavity, liver, laryngeal, cervical, and oropharyngeal cancer) in each of the WHO regions (African, Eastern Mediterranean, European, the Americas, South-East Asia Pacific, and Western Pacific) were obtained from the Institute for Health Metrics Evaluation global burden of disease dataset. Vaccine-preventable mortality was estimated considering the fraction attributable to infection, to estimate the number of deaths and YLL potentially preventable through vaccination. Data from the World Bank on GDP per capita were used to estimate the value of YLL (VYLL). The robustness of these results was explored with sensitivity analysis. Given that several Epstein-Barr virus (EBV) vaccines are in development, but not yet available, the impact of a potential vaccine for EBV was evaluated in a scenario analysis. RESULTS: In 2019, there were 465,740 potentially vaccine-preventable cancer deaths and 14,171,397 YLL across all WHO regions. The estimated economic impact due to this mortality was $106.3 billion globally. The sensitivity analysis calculated a range of 403,025-582,773 deaths and a range in productivity cost of $78.8-129.0 billion. In the scenario analysis EBV-related cancer mortality increased the global burden by 159,723 deaths and $32.4 billion. CONCLUSION: Overall, the findings from this analysis illustrate the high economic impact of premature cancer mortality that could be potentially preventable by vaccination which may assist decision-makers in allocating limited resources among competing priorities. Improved implementation and increased vaccination coverage of HPV and HBV should be prioritized to decrease this burden.

Waning of Humoral Immunity to Vaccine-Preventable Diseases in Children Treated for Acute Lymphoblastic Leukemia: A Single-Center Retrospective Cross-Sectional Analysis

Objective: The survival rates of children with acute lymphoblastic leukemia (ALL) have improved over the years, but infections remain a significant cause of morbidity and mortality. Chemotherapy has a range of harmful side effects including the loss of protective antibodies against vaccine-preventable diseases. The objective of this study was to evaluate the serological status of pediatric ALL cases before and after intensive chemotherapy. Materials and Methods: Children treated and followed for ALL at Dokuz Eylül University were included in this retrospective cross-sectional study. Antibody levels against hepatitis A, hepatitis B, and rubella were routinely assessed at both the time of diagnosis and 6 months after completion of chemotherapy. Measles, mumps, and varicella antibody levels were evaluated at only 6 months after treatment. Results: Seventy-eight children who completed chemotherapy for ALL were enrolled in the study. All participants had non-protective antibody levels for at least one of the diseases. The highest seropositivity rate was found for hepatitis A (55.1%) and the lowest for measles (17.9%) after chemotherapy. Overall, 50.7%, 30.6%, and 45.7% of the patients significantly lost their humoral immunity against hepatitis B, hepatitis A, and rubella, respectively. Patients in the higher-risk group for ALL had lower seropositivity rates than patients of the other risk groups. There were statistically significant relationships between the protective antibody rates for hepatitis A and varicella and the ages of the patients. Except for hepatitis A vaccination, pre-chemotherapy vaccination did not affect post-chemotherapy serology. On the other hand, all children with a history of varicella before diagnosis showed immunity after chemotherapy. Conclusion: Patients with ALL, including those previously fully vaccinated, are at great risk of infection due to the decrease in protective antibody levels after chemotherapy. There is a need for routine post-chemotherapy serological testing and re-vaccination based on the results obtained.

A worldwide overview for hexavalent vaccines and a glimpse into Turkiye's perspective.

The surge in recommended vaccinations for child's has spurred the development of combination vaccines, notably hexavalent vaccines, which provide multiple immunizations in a single dose. These vaccines offer various advantages, such as streamlining vaccination schedules, minimizing injection-related pain and exposure to preservatives, expanding vaccine coverage, and reducing administration costs. However, the intricate and expensive development of these vaccines presents substantial challenges, requiring increased investment and healthcare provider education to optimize their utilization and sustain high vaccination rates. Turkey, known for its robust vaccine coverage, strategic geographic location, and the influx of refugees, is at a critical juncture for integrating hexavalent vaccines into national programs. This transition is especially relevant given the rising vaccine hesitancy and the potential resurgence of vaccine-preventable diseases. This review assesses the deployment of hexavalent vaccines, examining their benefits and challenges through clinical trials and global experiences, with a specific emphasis on Turkiye's public health context.

Vaccine-Preventable Disease Outbreaks Among Healthcare Workers: A Scoping Review.

BACKGROUND: Outbreaks of vaccine-preventable diseases (VPDs) in healthcare workers (HCWs) can result in morbidity and mortality and cause significant disruptions to healthcare services, patients, and visitors as well as an added burden on the healthcare system. This scoping review aimed to describe the epidemiology of VPD outbreaks in HCWs caused by diseases that are prevented by the 10 vaccines recommended by the World Health Organization for HCWs. METHODS: In April 2022, CINAHL, MEDLINE, Global Health, and EMBASE were searched for all articles reporting on VPD outbreaks in HCWs since the year 2000. Articles were included regardless of language and study type. Clinical and epidemiological characteristics of VPD outbreaks were described. RESULTS: Our search found 9363 articles, of which 216 met the inclusion criteria. Studies describing 6 of the 10 VPDs were found: influenza, measles, varicella, tuberculosis, pertussis, and rubella. Most articles (93%) were from high- and upper-middle-income countries. While most outbreaks occurred in hospitals, several influenza outbreaks were reported in long-term-care facilities. Based on available data, vaccination rates among HCWs were rarely reported. CONCLUSIONS: We describe several VPD outbreaks in HCWs from 2000 to April 2022. The review emphasizes the need to understand the factors influencing outbreaks in HCWs and highlights the importance of vaccination among HCWs.

A Review of the Resurgence of Measles, a Vaccine-Preventable Disease, as Current Concerns Contrast with Past Hopes for Measles Elimination.

On 22 February 2024, the World Health Organization (WHO) stated that, following the recent resurgence of measles cases in Europe, more than half the world's countries could expect significant measles outbreaks this year. Measles is a highly infectious virus with a primary case reproduction number (R0) of 12-18. Measles infection can be severe, resulting in pneumonia, and also more rarely in subacute sclerosing panencephalitis (SSPE), which occurs in 1 child out of every 1,000 and can be fatal. Until the 1990s, the hope of eliminating measles seemed possible following the successful development of effective vaccines, given individually or in the combined measles, mumps, and rubella (MMR) vaccine. Vaccine hesitancy due to misinformation about possible vaccine side effects, reduced vaccine uptake during and after the COVID-19 pandemic, and lack of awareness of the severe consequences of measles infection have contributed to low vaccine uptake, resulting in vulnerable communities. This article aims to review the recent resurgence of measles cases in the US, Europe, and the UK, to provide a reminder of the potential severity of measles, and to consider the causes of the failure to eliminate this vaccine-preventable viral infection.

Effectiveness of interventions to increase healthcare workers' adherence to vaccination against vaccine-preventable diseases: a systematic review and meta-analysis, 1993 to 2022.

BackgroundVaccination adherence among healthcare workers (HCWs) is fundamental for the prevention of vaccine-preventable diseases (VPDs) in healthcare. This safeguards HCWs' well-being, prevents transmission of infections to vulnerable patients and contributes to public health.AimThis systematic review and meta-analysis aimed to describe interventions meant to increase HCWs' adherence to vaccination and estimate the effectiveness of these interventions.MethodsWe searched literature in eight databases and performed manual searches in relevant journals and the reference lists of retrieved articles. The study population included any HCW with potential occupational exposure to VPDs. We included experimental and quasi-experimental studies presenting interventions aimed at increasing HCWs' adherence to vaccination against VPDs. The post-intervention vaccination adherence rate was set as the main outcome. We included the effect of interventions in the random-effects and subgroup meta-analyses.ResultsThe systematic review considered 48 studies on influenza and Tdap vaccination from database and manual searches, and 43 were meta-analysed. A statistically significant, positive effect was seen in multi-component interventions in randomised controlled trials (relative risk (RR) = 1.37; 95% CI: 1.13-1.66) and in observational studies (RR = 1.43; 95% CI: 1.29-1.58). Vaccination adherence rate was higher in community care facilities (RR = 1.58; 95% CI: 1.49-1.68) than in hospitals (RR = 1.24; 95% CI: 0.76-2.05).ConclusionInterventions aimed at increasing HCWs' adherence to vaccination against VPDs are effective, especially multi-component ones. Future research should determine the most effective framework of interventions for each setting, using appropriate study design for their evaluation, and should compare intervention components to understand their contribution to the effectiveness.

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.

Impact of a research-action on vaccination indicators in the state of Minas Gerais, Brazil.

OBJECTIVE: Analyze the impact of the state research-action project on immunization indicators (vaccination coverage - VC, homogeneity of vaccination coverage - HVC, dropout rate - DR, and risk rating) before and after the intervention in municipalities and priority Regional Health Administrations/Regional Health Superintendencies (RHA/RHS). METHODS: The state research-action project was a before-after community clinical trial conducted in 212 municipalities belonging to eight RHA/RHS in the state of Minas Gerais, Brazil. The study sample comprised RHA/RHS with a decreasing trend for routine vaccination coverage in children under one year from 2015 to 2020. This study used secondary VC and DR data from 10 immunobiologicals recommended for children younger than two years from January to December 2021 (pre-intervention period, prior to the state research-action project) and from January to December 2022 (post-intervention period). The categorical variables were presented in proportions, and initially, a comparison was made between those of DR, HVC, and the risk rating for the transmission of vaccine-preventable diseases, according to the two periods (2021 and 2022), using the McNemar test. RESULTS: All immunization indicators increased after conducting the research-action project. In 2021, 80.66% of the state's municipalities had a risk rating for the transmission of vaccine-preventable diseases as "high and very high." In 2022, the value reduced to 68.40%. CONCLUSIONS: Risk rating for the transmission of vaccine-preventable diseases is an important mechanism to assist managers in defining priorities. The state research-action project used a method that enabled the construction and execution of unique action plans for each municipality, directing the improvement of immunization indicators in the state.

Prevalence of infectious diseases, immunity to vaccine-preventable diseases and chronic medical conditions among Ukrainian refugees in Germany - A cross sectional study from the German Network University Medicine (NUM).

BACKGROUND: Vulnerability to infectious diseases in refugees is dependent on country of origin, flight routes, and conditions. Information on specific medical needs of different groups of refugees is lacking. We assessed the prevalence of infectious diseases, immunity to vaccine-preventable diseases, and chronic medical conditions in children, adolescents, and adult refugees from Ukraine who arrived in Germany in 2022. METHODS: Using different media, we recruited Ukrainian refugees at 13 sites between 9-12/2022. An antigen test for acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) infection, serologies for a range of vaccine-preventable diseases, as well as interferon gamma release assays (IGRAs) for tuberculosis (TB), and SARS-CoV-2 were performed. We assessed personal and family history of chronic medical conditions, infectious diseases, vaccination status, and conditions during migration. RESULTS: Overall, 1793 refugees (1401 adults and 392 children/adolescents) were included. Most participants were females (n = 1307; 72·3%) and from Eastern or Southern Ukraine. TB IGRA was positive in 13% (n = 184) of the adults and in 2% (n = 7) of the children. Serology-based immunological response was insufficient in approximately 21% (360/1793) of the participants for measles, 32% (572/1793) for diphtheria, and 74% (1289/1793) for hepatitis B. CONCLUSIONS: We show evidence of low serological response to vaccine-preventable infections and increased LTBI prevalence in Ukrainian refugees. These findings should be integrated into guidelines for screening and treatment of infectious diseases in migrants and refugees in Germany and Europe. Furthermore, low immunity for vaccine-preventable diseases in Ukrainians independent of their refugee status, calls for tailor-made communication efforts.

Investigating sources of non-response bias in a population-based seroprevalence study of vaccine-preventable diseases in the Netherlands.

BACKGROUND: PIENTER 3 (P3), conducted in 2016/17, is the most recent of three nationwide serological surveys in the Netherlands. The surveys aim to monitor the effects of the National Immunisation Programme (NIP) by assessing population seroprevalence of included vaccine preventable diseases (VPDs). The response rate to the main sample was 15.7% (n = 4,983), following a decreasing trend in response compared to the previous two PIENTER studies (P1, 55.0%; 1995/1996 [n = 8,356] and P2, 33.0%; 2006/2007 [n = 5,834]). Non-responders to the main P3 survey were followed-up to complete a "non-response" questionnaire, an abridged 9-question version of the main survey covering demographics, health, and vaccination status. We assess P3 representativeness and potential sources of non-response bias, and trends in decreasing participation rates across all PIENTER studies. METHODS: P3 invitees were classified into survey response types: Full Participants (FP), Questionnaire Only (QO), Non-Response Questionnaire (NRQ) and Absolute Non-Responders (ANR). FP demographic and health indicator data were compared with Dutch national statistics, and then the response types were compared to each other. Random forest algorithms were used to predict response type. Finally, FPs from all three PIENTERs were compared to investigate the profile of survey participants through time. RESULTS: P3 FPs were in general healthier, younger and higher educated than the Dutch population. Random forest was not able to differentiate between FPs and ANRs, but when predicting FPs from NRQs we found evidence of healthy-responder bias. Participants of the three PIENTERs were found to be similar and are therefore comparable through time, but in line with national trends we found P3 participants were less inclined to vaccinate than previous cohorts. DISCUSSION: The PIENTER biobank is a powerful tool to monitor population-level protection against VPDs across 30 years in The Netherlands. However, future PIENTER studies should continue to focus on improving recruitment from under-represented groups, potentially by considering alternative and mixed survey modes to improve both overall and subgroup-specific response. Whilst non-responder bias is unlikely to affect seroprevalence estimates of high-coverage vaccines, the primary aim of the PIENTER biobank, other studies with varied vaccination/disease exposures should consider the influence of bias carefully.

The immune status of migrant populations in Europe and implications for vaccine-preventable disease control: a systematic review and meta-analysis.

BACKGROUND: Ensuring vaccination coverage reaches established herd immunity thresholds (HITs) is the cornerstone of any vaccination programme. Diverse migrant populations in European countries have been associated with cases of vaccine-preventable diseases (VPDs) and outbreaks, yet it is not clear to what extent they are an under-immunized group. METHODS: We did a systematic review and meta-analysis to synthesize peer-reviewed published primary research reporting data on the immune status of migrants in EU/EEA countries, the UK and Switzerland, calculating their pooled immunity coverage for measles, mumps, rubella and diphtheria using random-effects models. We searched on Web of Science, Embase, Global Health and MEDLINE (1 January 2000 to 10 June 2022), with no language restrictions. The protocol is registered with PROSPERO (CRD42018103666). FINDINGS: Of 1103 abstracts screened, 62 met eligibility criteria, of which 39 were included in the meta-analysis. The meta-analysis included 75 089 migrants, predominantly from outside Europe. Pooled immunity coverage among migrant populations was well below the recommended HIT for diphtheria (n = 7, 57.4% [95% confidence interval (CI): 43.1-71.7%] I2 = 99% vs HIT 83-86%), measles (n = 21, 83.7% [95% CI: 79.2-88.2] I2 = 99% vs HIT 93-95%) and mumps (n = 8, 67.1% [95% CI: 50.6-83.6] I2 = 99% vs HIT 88-93%) and midway for rubella (n = 29, 85.6% [95% CI: 83.1-88.1%] I2 = 99% vs HIT 83-94%), with high heterogeneity across studies. INTERPRETATION: Migrants in Europe are an under-immunized group for a range of important VPDs, with this study reinforcing the importance of engaging children, adolescents and adults in 'catch-up' vaccination initiatives on arrival for vaccines, doses and boosters they may have missed in their home countries. Co-designing strategies to strengthen catch-up vaccination across the life course in under-immunized groups is an important next step if we are to meet European and global targets for VPD elimination and control and ensure vaccine equity.

2022 Polio outbreak, Rockland County, NY: Cost evaluation of strategies to prevent future outbreaks of vaccine-preventable diseases.

In 1994, the World Health Organization Region of the Americas was declared polio-free. In July 2022, a confirmed case of paralytic polio in an unvaccinated adult resident of Rockland County, New York was reported by the New York State Department of Health (NYSDOH) and Rockland County Department of Health (RCDOH). While only one case was identified, a single case of paralytic polio represents a public health emergency in the United States. The patient's county of residence was identified to have low vaccination coverage indicating that the community was at risk for additional cases. Disease outbreaks are resource-intensive and incur high costs to the patient, local health departments, and to society. These costs are potentially avoidable for vaccine-preventable diseases and thus, highlight the urgency to not only interrupt transmission but to prevent future vaccine-preventable disease outbreaks by improving vaccination coverage. Following case confirmation, an investigation and response was initiated by NYSDOH, along with local health departments and the Centers for Disease Control and Prevention (CDC). After the initial investigation and response, collaborative efforts to mitigate risk and strengthen routine immunization continued, which included provider outreach and immunization record assessments of Head Start and licensed childcare facilities (primarily those with missing or incomplete required vaccination coverage reports from the previous year) in Rockland County. We estimated the costs of (1) provider outreach and (2) childcare and pre-kindergarten immunization record assessments of select licensed childcare and Head Start facilities in Rockland County. The total labor cost incurred for these activities was $138,514 with a total of 2,555 h incurred. Often there are unique opportunities in the midst of an outbreak for public health to implement activities to proactively address low vaccination and strengthen vaccination coverage and possibly prevent future outbreaks. Understanding the cost of these activities might help inform future outbreak planning.