Search Results (88)

Background: The 2022 conflict in Ukraine triggered mass migration, leading to a significant influx of Ukrainian refugee children into Poland. This situation raises concerns about hepatitis B virus immunity, as Ukraine’s hepatitis B vaccination coverage has been inconsistent compared to Poland’s high vaccination rates. Objective: To evaluate hepatitis B immunity and infection prevalence among Ukrainian refugee children residing in Southern Poland and to assess implications for vaccination strategies in the host country. Methods: A prospective cross-sectional study was conducted on 1322 Ukrainian refugee children (0–18 years) presenting to a pediatric infectious diseases department in Southern Poland between February 2022 and March 2024. Data on vaccination history, demographic characteristics, and selected laboratory parameters, including hepatitis B surface antigen and anti-HBs antibody levels, were collected. Protective immunity was defined as anti-HBs antibody levels ≥10 IU/L. Results: Among the participants (mean age 9.9 years; 50.2% female), 83.2% were reported as vaccinated according to national immunization programs, but only 64.9% demonstrated protective anti-HBs antibody levels. Protective antibody prevalence declined significantly with age, with less than half of adolescents aged 15–18 years showing immunity. Five children (0.4%) were diagnosed with chronic hepatitis B, four of whom were unvaccinated. Conclusions: This study identifies a significant gap in hepatitis B immunity among Ukrainian adolescent refugees residing in Southern Poland, with less than half possessing protective anti-HBs antibody levels. This immunity gap and the high risk of sexual transmission of the hepatitis B virus in adolescents highlight the urgent need for comprehensive surveillance, screening, and catch-up vaccination programs. Full article

Cervical cancer remains a significant global public health challenge, with human papillomavirus (HPV) as its primary cause. In response, the World Health Organization (WHO) launched a global strategy to eliminate cervical cancer by 2030 and, in its 2022 position paper, recommended a single-dose vaccination schedule. The objective of this review is to critically examine the current HPV vaccination landscape in China, including vaccination policies, immunization schedules, supply–demand dynamics, and the feasibility of transitioning to a single-dose regimen. By synthesizing recent developments in HPV virology, epidemiology, vaccine types, and immunization strategies, we identify both opportunities and barriers unique to the Chinese context. Results indicate that China primarily adheres to a three-dose vaccination schedule, with an optional two-dose schedule for girls aged 9–14, leaving a notable gap compared to the most recent WHO recommendation. The high prevalence of HPV types 52 and 58 contributes to a distinct regional infection pattern, underscoring the specific need for nine-valent vaccines tailored to China’s epidemiological profile. Despite the growing demand, vaccine supply remains inadequate, with an estimated annual shortfall of more than 15 million doses. This issue is further complicated by strong public preference for the nine-valent vaccine and the relatively high cost of vaccination. Emerging evidence supports the comparable efficacy and durable protection of a single-dose schedule, which could substantially reduce financial and logistical burdens while expanding coverage. This review advocates for the adoption of a simplified single-dose regimen, supported by catch-up strategies for older cohorts and the integration of HPV vaccination into China’s National Immunization Program (NIP). Sustained investment in domestic vaccine development and centralized procurement of imported vaccines may also possibly alleviate supply shortage. These coordinated efforts are critical for strengthening HPV-related disease prevention and accelerating China’s progress toward the WHO’s cervical cancer elimination targets. Full article

Background/Objectives: Adult vaccination remains suboptimal, particularly among older adults and individuals with chronic conditions. Hospitals represent a strategic setting for improving vaccination coverage among these high-risk populations. This systematic review and meta-analysis evaluated hospital-based interventions aimed at enhancing vaccine uptake in adults aged ≥60 years or 18–64 years with at-risk medical conditions. Methods: We conducted a systematic review and meta-analysis following PRISMA and MOOSE guidelines. Searches in PubMed, EMBASE, and Scopus identified studies published in the last 10 years evaluating hospital-based interventions reporting vaccination uptake. The risk of bias was assessed using validated tools (NOS, RoB 2, ROBINS-I, QI-MQCS). A meta-analysis was conducted for categories with ≥3 eligible studies reporting pre- and post-intervention vaccination coverage in the same population. Results: We included 44 studies. Multi-component strategies (n = 21) showed the most consistent results (e.g., pneumococcal uptake from 2.2% to 43.4%, p < 0.001). Reminder-based interventions (n = 4) achieved influenza coverage increases from 31.0% to 68.0% and a COVID-19 booster uptake boost of +38% after SMS reminders. Educational strategies (n = 11) varied in effectiveness, with one study reporting influenza coverage rising from 1.6% to 12.2% (+662.5%, OR 8.86, p < 0.01). Standing order protocols increased pneumococcal vaccination from 10% to 60% in high-risk adults. Hospital-based catch-up programs improved DTaP-IPV uptake from 56.2% to 80.8% (p < 0.001). For patient education, the pooled OR was 2.11 (95% CI: 1.96–2.27; p < 0.001, I² = 97.2%) under a fixed-effects model, and 2.47 (95% CI: 1.53–3.98; p < 0.001) under a random-effects model. For multi-component strategies, the OR was 2.39 (95% CI: 2.33–2.44; p < 0.001, I² = 98.0%) with fixed effects, and 3.12 (95% CI: 2.49–3.92; p < 0.001) with random effects. No publication bias was detected. Conclusions: Hospital-based interventions, particularly those using multi-component approaches, effectively improve vaccine coverage in older and high-risk adults. Embedding vaccination into routine hospital care offers a scalable opportunity to reduce disparities and enhance population-level protection. Future policies should prioritize the institutional integration of such strategies to support healthy aging and vaccine equity. Full article

Introduction: In 2008, Mexico initiated its national HPV vaccination program targeting adolescent girls. This study aims to evaluate the current status of the program, analyzing trends in vaccine acquisition, administration, and coverage over a 16-year period. Materials and Methods: A retrospective longitudinal study was conducted using secondary data from 2008 to 2023. Official records from three major public health institutions—IMSS, ISSSTE, and SSA—were reviewed to assess HPV vaccine procurement and administration. Results: Significant fluctuations were identified in the number of doses acquired, administered, and the corresponding coverage rates. A marked decline was observed between 2019 and 2021, followed by a sharp increase in 2022 and 2023. Over the entire period, an estimated 6.8 million doses were not administered to the intended target population. Furthermore, 2.6 million doses were administered in excess of the number officially acquired, indicating possible discrepancies in data reporting or vaccine inventory management. Discussion: The findings revealed substantial inconsistencies in vaccine procurement, administration, and coverage across institutions. While IMSS and ISSSTE consistently reported coverage below the theoretical target, SSA occasionally exceeded expectations, potentially compensating for deficits elsewhere. Nevertheless, national coverage remained inadequate in several years, with notable disparities between institutions. These gaps highlight systemic weaknesses in program coordination, planning, and data transparency, contributing to millions of unvaccinated individuals. Conclusions: This study offers a comprehensive analysis of Mexico’s HPV vaccination program, uncovering critical irregularities in its implementation. Challenges include inaccurate target population estimation, inconsistencies between vaccine acquisition and administration, and limited data reliability. Despite some progress in recent years, particularly in the post-pandemic years, the program requires urgent restructuring. This includes implementing a national catch-up strategy, expanding vaccine eligibility, and strengthening surveillance systems to ensure equitable and effective coverage toward the elimination of cervical cancer. Full article

Background/Objectives: In the Republic of Serbia, measles vaccination was first introduced in 1971, while combined vaccination (measles, mumps, rubella) was made mandatory in 1996 as part of the national vaccination program. Reported prevalence values for 2023 were <0.75 cases per 100K population for measles, 0.09 cases per 100K for mumps, and no cases of rubella. Methods: This cross-sectional study was performed in May, 2024 as part of the project “Herd Immunity to Vaccine-Preventable and Other Relevant Infections in the Belgradian Population.” It focused on assessing herd immunity to measles, mumps and rubella (MMR) among residents insofar as these remain a public concern despite the availability of vaccines. A total of 2533 subjects were distributed across nine age groups, covering those aged 1–70⁺ years and various professional groups residing in Belgrade. Participants were stratified by age and activity. Upon obtaining individual information by online questionnaire and receiving a signed statement of informed consent, blood samples were obtained for IgG antibody testing (ELISA) to determine MMR serological status. The results were compared to national and international immunization standards to evaluate herd immunity levels. Results: Our results indicate varying levels of immunity for each virus, with specific demographic groups showing different immunity levels. Total measles seroprevalence during this study was 74.7%, with significant variation across all age groups. While high seropositivity was observed in both children (90.7%) and elder age groups (98.4%), middle-aged individuals in the age group 30–49 years showed significantly lower IgG levels. Between 2021 and 2023, there were no registered cases of rubella detected in Serbia, which indicates a high level of immunity. This was confirmed here with consistently high IgG levels across all age groups, with an average seropositivity of 94.8%. Average mumps seropositivity across all age groups was 85.1%. The lowest value was in the young child (1–5 years) age group (76.1%); the highest was in the elderly group (92.6%). Conclusions: The current findings suggest that the Belgradian population has strong overall immunity to MMR, yet with some concerns regarding measles immunity in middle-aged adults, suggesting a potential need for catch-up vaccinations. While rubella status indicates strong herd immunity and minimal risk of outbreaks, mumps immunity in some groups (children, middle-aged adults) is below the protective threshold. While it is still sufficient to prevent widespread transmission, it should be closely observed. To our knowledge, this study is the first of its kind to provide data about MMR seroprevalence in Belgrade. Findings indicate the need for constant surveillance and revaccination of vulnerable/seronegative groups. Full article

Background/Objectives: In France, non-pharmaceutical interventions (NPIs) implemented to control COVID-19 led to a significant decline in invasive meningococcal disease (IMD) cases. However, a rebound in cases, particularly for serogroups W and Y, was observed after the gradual lifting of NPIs, raising questions about an “immunity gap” due to reduced circulation of the bacteria. During the study period, vaccination against MenC was mandatory from 2018, and vaccination against MenB has been recommended since 2022. Methods: We conducted a retrospective seroepidemiological study using 166 normal sera collected between 2016 and 2024. Anti-Neisseria meningitidis IgG levels were quantified by ELISA using purified capsular polysaccharides for serogroups B, C, W, Y, and X. Samples were categorized into three periods: pre-NPIs (n = 72), during NPIs (n = 33), and post-NPIs (n = 61). Statistical comparisons were performed using Kruskal–Wallis tests for non-parametric data. Results: Our results show a significant decline in anti-serogroup B IgG antibody levels after the lifting of NPIs (p < 0.0001) in line with reduced circulation. Anti-serogroup C IgG antibody levels increased incrementally (p = 0.0003), particularly in those aged 1–4 years, likely reflecting a catch-up in anti-meningococcal C vaccination coverage. Anti-serogroup W IgG antibody levels remained stable, suggesting sustained circulation, but shifted to young children in the post-NPI period, potentially due to a genotypic shift. Anti-serogroup Y IgG antibody levels transiently increased significantly (p < 0.0001) during the NPI period but then decreased back after their lifting. Anti-serogroup X IgG antibody levels remained stable, consistent with its low prevalence and the absence of targeted vaccination. Full article

The dynamic nature of infectious diseases introduces inherent challenges to the design of vaccine clinical trials, which consequently makes vaccine indirect treatment comparisons (ITCs) and meta-analyses (MAs) more challenging compared with regular pharmaceuticals. However, comparisons of efficacy and safety between vaccines are being frequently required in vaccine decision making due to a low number of head-to-head clinical trials in the vaccine landscape. The introduction of the European Union Health Technology Assessment (HTA) Regulation (EU HTAR) aims to harmonize HTA efforts across Europe. However, the EU HTAR could also escalate existing challenges for conducting vaccine MAs and ITCs. Such challenges include generating efficacy evidence in time for Joint Clinical Assessment (JCA), incorporating high levels of heterogeneity due to infectious disease-specific characteristics, and tackling a high number of PICOs per submission—likely driven by heterogeneity in the available data and differences in national vaccine calendars. Opportunities to tackle these challenges include introducing a stepwise approach to vaccine assessment in JCA, best-practice recommendations for conducting/interpreting vaccine MAs and ITCs, and condensing the number of PICOs to create larger ‘catch-all’ ITC networks. This perspective article explores these challenges and opportunities further. Full article

Human papillomavirus (HPV) infection remains a principal cause of cervical cancer worldwide. Although large-scale vaccination efforts have substantially lowered HPV infection rates and precancerous lesions, not all regions have achieved high coverage. In Japan, proactive HPV vaccine recommendations were suspended from 2013 to 2022 due to concerns over alleged adverse events, causing vaccination rates to drop from over 70% to below 1%. This narrative review synthesized research published from 2014 to 2025 in PubMed, Cochrane Library, and Google Scholar, focusing on English-language studies. Inclusion criteria encompassed analyses of HPV vaccine efficacy or safety, policies related to vaccination in Japan or other countries, and investigations into vaccine hesitancy or media influences. Data were categorized into five thematic areas: historical and policy contexts, evidence of vaccine safety and efficacy, societal drivers of hesitancy, communication strategies, and administrative or clinical interventions. Evidence robustly confirms the HPV vaccine’s favorable safety profile, with severe adverse events appearing exceedingly rare. Nonetheless, media sensationalism and limited risk communication in Japan perpetuated mistrust, impeding vaccination uptake. Comparisons with Denmark and Ireland indicate that transparent, interactive risk communication can restore coverage to near-pre-suspension levels. Japan’s recent policy reforms, including reinstating proactive recommendations and catch-up initiatives, have begun to reverse vaccination hesitancy. Sustained policy support, evidence-based messaging, and empathetic engagement with communities are central to rebuilding trust in the HPV vaccine. Lessons from best international practices emphasize the importance of multifaceted interventions, collaborative stakeholder engagement, and transparent risk communication to reduce the burden of HPV-related malignancies. Full article

Background: Given the significant impact of population immunity on the measles epidemic, understanding immunity differences among populations with varying immunity backgrounds is necessary for identifying immunity gaps and informing vaccination policies. In this study, we aimed to determine the distinct dynamics of vaccine-induced and naturally acquired antibodies, with specific focus on difference in vaccine-induced antibody responses across different birth cohorts. Methods: Based on two cohorts and one cross-sectional study conducted in Anhua County, Hunan Province, China, serum samples from children who followed China’s routine measles vaccination schedule (i.e., two-dose schedule at 8/18 months) and adults who acquired immunity through natural infection were tested for measles IgG antibodies using an enzyme-linked immunosorbent assay. The generalized additive mixed model and a mechanistic model were employed to describe antibody dynamics following vaccination and infections. Wavelet analysis was used to investigate the temporal relationship between the measles epidemic and long-term antibody levels after natural infection. Results: A total of 408 children (0–12 years) and 222 adults (54–84 years) were included in the present study. Vaccine-induced antibody levels following 8 m/18 m vaccination were estimated to fall below the protective threshold of 200 mIU/mL by age of 15.8, whereas antibody levels following infections remained high. The decay rate of vaccine-induced antibodies was estimated at 3.0 × 10⁻³ log-log mIU/mL per year, whereas naturally acquired measles antibodies persisted lifelong with a significantly lower decay rate of 2.30 × 10⁻⁵ log-log mIU/mL per year. Moreover, vaccine-induced antibody levels in children born after 2010—a period of low measles incidence—declined more rapidly (duration of protective immunity: 12.5 years), compared to those born before 2010. Discussion: Our findings revealed immunity heterogeneity among individuals with difference measles immunity backgrounds. In particular, the birth-cohort specific differences in vaccine-induced immunity highlighted the key role of young generations born in settings with low measles incidence in contributing to population immunity gaps. This underlines that greater attention should be given to this group in future catch-up vaccination efforts. Full article

Background and Objectives: Cervical cancer remains a critical public health challenge in Eastern Europe and Central Asia (EECA), where systemic barriers have hindered prevention efforts. This descriptive regional study evaluates progress toward achieving Target 1 of the WHO Global Strategy for Cervical Cancer Elimination—vaccinating 90% of girls by age 15—in 17 countries and territories. The research is situated within the context of the Regional Alliance for Cervical Cancer Prevention in EECA, a multi-stakeholder platform launched by UNFPA in 2021 to accelerate regional progress toward WHO targets. The Alliance supports countries through technical collaboration, shared learning, and political engagement. Therefore, as a secondary endpoint, the study explores possible correlations between national achievements and the post-2021 scale-up efforts supported by the Alliance. Methods: A standardized questionnaire, consolidated by United Nation Population Fund (UNFPA) technical experts, was disseminated in November 2024 to 17 national focal points, yielding 19 responses due to disaggregated submissions from Bosnia and Herzegovina. The survey collected data on HPV vaccination policies, delivery models, vaccine type, target populations, and coverage. Results: By late 2024, six countries had implemented HPV vaccination before 2021, while six more launched programs after the Regional Alliance’s formation in 2021. Coverage varied widely, from 0.2% in Brčko District to 99.3% in Uzbekistan. Most countries targeted girls aged 9–14, with increasing male inclusion and catch-up cohorts. Gardasil 4 was the most used vaccine, though Gardasil 9 is gaining ground. School-based and hybrid delivery strategies were associated with significantly higher coverage (p = 0.0121). Inferential analysis also showed significant variation by vaccine type (p = 0.0067) and a positive correlation with program maturity (ρ = 0.52, p = 0.067). However, findings should be interpreted considering limitations including reliance on self-reported country data and absence of independent validation. Conclusions: The results offer actionable insights into delivery models, gender inclusion, and regional disparities—supporting efforts to close the gap toward 2030 elimination targets in EECA Countries. Full article

Between 2016 and 2023, over 400,000 dogs in Greater Bangkok, Thailand, were sterilised and vaccinated against rabies through a Catch, Neuter, Vaccinate, Return (CNVR) programme. CNVR is practiced in many countries to humanely and effectively manage free-roaming dog populations, and to mitigate canine and human rabies risks. Residents were surveyed about their experiences, attitudes, and behaviours towards free-roaming dogs. Responses were evaluated in relation to respondents’ dog ownership status and the CNVR intensity within their local administrative area (0, 1, 2, or 3 CNVR rounds). The results show an overall positive effect of CNVR. A dose-dependent CNVR effect was observed with residents’ perceptions of declines in free-roaming dog populations and puppies born in their community, as well as in being “troubled” by free-roaming dogs now versus before the intervention. Residents living in areas with the highest levels of CNVR also had lower odds of reporting a dog bite. Some measures, including other current attitudes and behaviours towards free-roaming dogs, did not exhibit this dose-dependent effect. Dog owners showed higher levels of tolerance and care for street dogs than non-owners. The results suggest that owned dogs contributed substantially to the roaming dog population and must be considered in management efforts. CNVR appears to have delivered meaningful benefits to Greater Bangkok residents, and the majority reported sterilisation as their preferred management approach. Full article

Greater Bangkok, Thailand, has large numbers of both owned and free-roaming dogs, two populations that intersect and overlap in complex and nuanced ways. A more robust understanding of owned dog populations is, therefore, important not only in supporting the welfare of owned dogs but also in managing free-roaming dog populations and protecting human health through the prevention of rabies transmission. Over 3200 residents were surveyed to explore the numbers and demographics of owned dogs in Greater Bangkok, plus owners’ attitudes and reported behaviours related to their dogs; the acquisition and loss of owned dogs; and caretaking by owners (confinement practices, sterilisation, rabies vaccination, and other veterinary care). The study also considered dog owners’ practices in relation to a Catch, Neuter, Vaccinate, Return (CNVR) programme designed to humanely manage dog populations and vaccinate dogs against rabies. Survey results indicate that there are approximately 1.3 million owned dogs in Greater Bangkok. Key findings include high reported rabies vaccination among owned dogs (84% in the past year). Fifty-three percent of owned dogs in the sample were reported to be sterilised, 66% were allowed to roam, and 46% of dogs acquired into households were adopted from the street. The CNVR programme appeared to impact the care and keeping of owned dogs in the community, as it was associated with greater confinement and sterilisation levels. Full article

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

Background: Invasive meningococcal disease (IMD) can lead to severe and fatal outcomes. Vaccines against meningococcus (serogroups B, MenB; or ACWY, MenACWY) are recommended for patients at high risk of developing IMD. Our aim was to identify high-risk patients through a systematic search of medical codes and to evaluate vaccination coverage by high-risk group. Methods: An observational retrospective study was conducted in patients discharged at Reina Sofía University Hospital (Cordoba, Spain) from 1 January 2000, to 31 December 2023. Selection of high-risk patients was conducted through national administrative and clinical databases and vaccination coverage was determined through the Andalusian electronic vaccine database. Vaccine coverages of MenB and MenACWY were calculated within risk groups. Finally, bivariate analyses were conducted to assess the potential association between coverage, sex, and the year of admission. Results: A total of 2689 patients with 2710 high-risk conditions for IMD were identified from the databases searched. Of the 1755 requiring MenB vaccination, only 624 (35.6%) had received one dose and 558 (31.8%) two doses. Of the 2710 requiring MenACWY vaccination, only 784 (28.9%) had received one dose and 520 (19.2%) two doses. Patients with properdin-complement deficiencies showed the lowest vaccination rates (<10%). For the rest of the high-risk groups, vaccination coverages were significantly lower when the condition was diagnosed before the immunization guideline recommendations (p < 0.001). Conclusions: The identification of high-risk patients through databases using R-coded algorithms is both feasible and effective for identifying and catching-up patients for vaccination. The population at risk of IMD lacks adequate meningococcal vaccination coverage. Our methodology can serve to identify patients in other regions and for different vaccines. Full article

Background/Objectives: Human papillomavirus (HPV) is linked to multiple cancers that can be prevented through vaccination. While the optimal age for vaccination is in childhood and adolescence, vaccination recommendations include adults through age 26 who missed childhood/adolescent vaccination. There are limited data about disparities among adults eligible for catch-up HPV vaccination. We conducted a comprehensive examination of HPV vaccination among US young adults, disaggregating the group by race/ethnicity and nativity status to identify subgroups that may require additional interventions. Methods: We analyzed 2019 and 2022 data of individuals aged 18–26 years from the National Health Interview Survey. Generalized linear models using Poisson regression with log link were used to examine the receipt of 1+ dose of HPV vaccine, race/ethnicity, and nativity (i.e., US- versus foreign-born) status. Results: The overall receipt of 1+ doses of HPV vaccine was 47.5%. The vaccination rate among the US-born group was 49.7% versus 31.9% among the foreign-born group with an adjusted prevalence ratio (APR) of 0.72; (95% CI, 0.62–0.82). Foreign-born non-Hispanic (NH) Black individuals (APR 0.31; 95% CI, 0.13–0.70) were less likely to be vaccinated against HPV than foreign-born NH White individuals, while US-born NH Asians (APR 1.27; 95% CI, 1.09–1.48) had a higher prevalence of the vaccination than the US-born NH White group. Additionally, foreign-born NH Asian (APR 0.60; 95% CI, 0.46–0.77), NH Black (APR 0.27; 95% CI, 0.12–0.61), and Hispanic (APR 0.76; 95% CI, 0.60–0.97) populations were less likely to be vaccinated than their respective US-born counterparts. Conclusion: Profound HPV vaccination inequalities exist among US young adults with particularly low vaccine coverage among racially and ethnically minoritized immigrant populations. Full article