Search Results (78)

Background: Despite the widespread implementation of childhood vaccination programmes, hepatitis B virus (HBV) infection remains an ongoing occupational risk for healthcare students. In multi-ethnic and international university settings, differences in vaccination programmes and immune responses must be considered. This retrospective study aimed to assess the prevalence of protective levels of anti-HBs among medical students at an international university in Rome, exploring associations with demographic and vaccination-related factors. Methods: Data were collected from routine occupational health surveillance conducted in 2023. Anti-HB titres were measured in 507 students, and information on age, sex, country of birth, age at vaccination, and time since the last dose was analysed. Results: Overall, 55.0% of students had antibody levels of at least 10 mIU/mL, indicating serological protection. Higher seroprotection rates were observed among students vaccinated in the first year of life compared to those vaccinated later. A significant decline in antibody titres was also associated with longer intervals since vaccination. Students born outside Europe tended to show lower levels of protection. Conclusions: These results emphasise the importance of screening future healthcare professionals and continuously monitoring antibody titres to help reduce HBV infections. Full article

Background: Immunization coverage in Nigeria is low, with many children missing out on important lifesaving vaccines. To enable a better understanding of contextual factors towards increasing uptake, we piloted a Decentralized Immunization Monitoring (DIM) approach in the Kumbotso local government area (LGA) of Kano state, Nigeria, to identify wards with low vaccination rates and understand why this is happening. The findings were used to improve routine immunization (RI) programs and reduce the number of unvaccinated children and children yet to receive their first dose of diphtheria–pertussis–tetanus (DPT) vaccine, referred to as Zero-Dose children (ZD). Methods: This study adopted a cross-sectional design approach using the Behavioural and Social Drivers of Vaccination (BeSD) framework and the Lot Quality Assurance Sampling (LQAS). The study population comprised caregivers of children aged 0–11 months and 12–23 months across the 11 wards in Kumbotso District, Kano State, Nigeria, using a segmentation sampling approach. The study covered 209 settlements selected using probability proportionate to size (PPS) sampling from the wards. Univariate and bivariate analyses were performed to show patterns and relations across variables. Results: Out of 418 caregivers surveyed, 98.1% were female. Delayed vaccination was experienced by 21.9% of children aged 4.5–11 months, while the prevalence of ZD was estimated at 26.8% amongst the older cohort (12–23 months). A total of 71.4% of the delayed group and 89.1% of the ZD group remained unvaccinated. Caregiver education, rural residence, and home births correlated with delayed/ZD status (p < 0.05). Logistic regression associated higher caregiver education with reduced delayed vaccination odds (OR:0.34, p < 0.001) and urban residence with lower ZD odds (OR:1.89, p = 0.036). The antigen coverages of BCG (81.5%), DPT3 (63.6%), and measles 1 (59.7%) all surpassed the national dropout thresholds. Kumbotso, Unguwar Rimi, and Kureken Sani wards were all identified as underperforming and therefore targeted for intervention. Negative vaccine perceptions (50% delayed, 53.6% ZD) and distrust in health workers (46.4% delayed, 48.2% ZD) were significant barriers, though the caregiver intent to vaccinate was protective (OR: 0.27, p < 0.001). The cost of accessing immunization services appeared to have a minor effect on coverage, as the majority of caregivers of delayed and ZD children reported spending less than 200 Naira (equivalent to USD 0.15) on transport. Conclusions: This pilot study highlighted the utility of LQAS and BeSD in identifying low-performing wards, barriers, and routine immunization gaps. Barriers included low caregiver education, rural residence, and negative vaccine perceptions/safety. Caregiver education and urban residence were protective factors against delayed and ZD vaccination, suggesting social and systemic barriers, particularly in rural and less educated populations. Antigen-specific coverage showed disparities, with dropouts for multi-dose vaccines exceeding the national thresholds of 10%. Targeted measures addressing education, trust, and systemic issues are needed. Findings emphasize decentralized monitoring, community engagement, and context-specific strategies to reduce ZD children and ensure equitable vaccination in Nigeria. 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

Clostridioides difficile is an anaerobic bacterium that causes disease in both animals and humans. Despite the known significance of this agent, there are no commercial vaccines available for humans, and only one immunogen is marketed for swine. However, no studies have evaluated this vaccine. Background/Objectives: Therefore, the aim of this study was to assess the potency of the first commercial vaccine for C. difficile infection in piglets and to compare the humoral response in rabbits and sows. Methods: Pregnant sows were divided into two groups: a vaccinated group (n = 12), receiving two doses before farrowing, according to the manufacturer’s recommendation, and an unvaccinated control group (n = 6). Blood samples were taken from sows and also from piglets up to two days after birth. In addition, two groups of New Zealand rabbits (Oryctolagus cuniculus) received either a half-dose (G1) or a full-dose (G2) of the vaccine, with a control group receiving sterile saline (0.85%). Rabbits were vaccinated twice, 21 days apart, with blood samples collected before each dose and 14 days after the final dose. A serum neutralization assay in Vero cells was performed to evaluate the titers of neutralizing antibodies. Results: The vaccine demonstrated immunogenicity by stimulating the production of neutralizing antibodies in both rabbits and sows. Additionally, these antibodies were passively transferred to piglets through colostrum, reaching levels comparable to those found in sows. Furthermore, vaccinated rabbits developed antibody titers that do not significantly differ from those obtained in sows and piglets. Conclusions: The tested vaccine can induce a humoral immune response against C. difficile A/B toxins in sows and these antibodies are passively transferred to neonatal piglets through colostrum. Also, the vaccination of rabbits might be a useful alternative for evaluating the potency of vaccines against C. difficile. Full article

Background/Objectives: Human papillomavirus (HPV) is a recognized cause of cervical cancer and is associated with several other malignancies, including those affecting the vagina, vulva, anus, penis, and head and neck. The introduction of the HPV vaccine has enabled the prevention of HPV-related cancers. This study aimed to determine the HPV vaccination coverage and examine trends in HPV vaccination in Croatia from 2016 to 2023 in the context of the national vaccination program. Methods: This retrospective study analyzed the aggregated school doctors’ data from 2016 to 2023. HPV vaccination coverages within the 2000–2008 birth cohorts were assessed based on the number of doses administrated, sex, and vaccination schedule, while for the trend analysis joinpoint regression was used. The vaccination coverage between sexes was tested using the chi-square test for trends and their ratio was calculated. Results: The HPV full-dose vaccination coverage increased significantly among the observed birth cohorts, from 4.49% in 2000 to 36.88% in 2008, with an APC = 33.97 and 95% CI: 29.37–42.43 (females from 7.74% to 44.98%, males from 1.44% to 29.14%). The highest recorded vaccination coverage was in the one-dose category (2008 female—52.78%). The vaccination coverage of females was significantly higher than that of males (the chi-square for the linear trend = 659.59, p < 0.001) and the female–male ratio decreased from 5.39 in 2000 to 1.54 in 2008. Conclusions: In Croatia, HPV vaccination coverage has increased since the introduction of the national HPV vaccination program. This positive trend was present in both sexes, and the rate ratio between female and male cohorts decreased. Full article

Background: This study aims to analyze the vaccination status and factors influencing delayed vaccination among toddlers born to hepatitis B surface antigen (HBsAg)-positive mothers. Methods: Data of HBsAg-positive mothers between 1 January 2021 and 31 December 2022 were provided by the Suzhou Maternal and Child Health Care and Family Planning Service Center. The vaccination records were obtained from the Jiangsu Province Immunization Service Management Information System. Logistic regression analysis was used to analyze influencing factors of delayed vaccination. Results: A total of 4250 toddlers born to HBsAg-positive mothers were documented. The data revealed that the first dose of the hepatitis B vaccine was administered to 100% of the toddlers. In addition, the coverage of the National Immunization Program (NIP) vaccines among these toddlers ranged from 92.9% to 99.4%. The proportion of delayed NIP vaccination varied between 0% and 12.2%. The proportion of delayed Bacillus Calmette–Guérin (BCG) vaccination was 11.3%, with the delay predominantly observed between 4 and 6 months. Notably, the proportion of delayed BCG vaccination among the toddlers born to HBsAg-positive mothers was significantly higher than that in the general population. Additionally, the proportion of the first dose of non-NIP vaccines was 3.3–36.4%, and the proportion of DTaP-IPV/Hib was 27.0%. Logistic regression analysis revealed that the regional level, the mother’s human papillomavirus (HPV) vaccination status, and the infant’s birth weight were significant factors influencing the timeliness of vaccination. Conclusions: Although the vaccination status of toddlers born to HBsAg-positive mothers in Suzhou city remains stable, the issue of delayed vaccination requires attention. It is essential to continue strengthening targeted vaccine education to reduce vaccine hesitancy and improve the rate of timely vaccination. Full article

Background: Immunization coverage varies across Papua New Guinea. In East New Britain (ENB) Province in 2022, only 65.5% and 50.2% of children under one year received their first dose of pentavalent (DTP1) and measles–rubella (MR1) vaccine, respectively. This study aimed to examine barriers and enablers to routine immunization in areas of un(der)-vaccination in ENB. Methods: A face-to-face survey was conducted with caregivers of children aged 12–23 months in ENB. We used Poisson regression to calculate incidence rate ratios (IRR) and 95% confidence intervals (95% CI) for factors associated with timely receipt of DTP1 or MR1 vaccines, defined as a child who was vaccinated between –2 and +30 days of the vaccine schedule. Delayed receipt is defined as a child who was vaccinated >30 days from the recommended due date. Results: Among 237 caregivers surveyed, 59.9% of children were vaccinated within the “timely” window for DTP1 and 34.1% for MR1. Timely DTP1 receipt was associated with a facility-based birth (IRR:1.93; 95% CI: 1.10–3.38) and trusting healthcare workers “very much”, compared to “a little or moderately” (IRR:1.53; 95% CI: 1.17–1.99). For MR1, the caregiver having completed tertiary/vocational education (IRR:1.79; 95% CI: 1.15–2.78), reporting taking a child to be vaccinated is affordable (IRR:1.52; 95% CI: 1.04–2.22), and healthcare workers explaining immunization services and answering associated questions (IRR:1.68; 95% CI: 1.18–2.41) were associated with timely vaccination. Conclusions: Activities to improve timely vaccination in ENB could include strengthening healthcare worker interpersonal communication skills to optimize trust and incentivizing women to give birth in a health facility. Full article

Respiratory syncytial virus (RSV) causes significant morbidity and mortality, especially in young children and the elderly. RSV vaccine development puzzled vaccinologists for years. Safety concerns of initial formulations, the lack of an absolute correlate of protection, and the need for selecting appropriate virus attenuation and antigen–adjuvant combinations contributed to delayed vaccine production. The recent stabilization of the RSV-F glycoprotein in the prefusion (preF) conformation that constitutes the primary target of RSV-neutralizing antibodies was key for efficient vaccine design. Two protein subunit vaccines (GSK’s Arexvy and Pfizer’s Abrysvo) and one mRNA RSV vaccine (Moderna’s mRESVIA) are now available. This article aims to provide a comparative overview of the safety and efficacy of novel RSV vaccines that are approved for the prevention of RSV-lower respiratory tract disease (LRTD) in adults 60 years of age and older, with updated recommendations calling for the expansion of vaccination to all adults at increased risk for severe RSV disease. Abrysvo is the only vaccine indicated for use in pregnancy to prevent RSV-LRTD in infants from birth to 6 months of age. We provide a comparative assessment of the efficacy of approved RSV vaccines over a maximum of three seasons, summarizing currently available data. We conclude that despite the decreasing vaccine efficacy over time, which should be anticipated for a virus that is characterized by short-term immunity, efficacy was clinically meaningful over placebo. The increased risk of Guillain–Barré syndrome post vaccination with Abrysvo or Arexvy, which prompted the FDA to require the inclusion of such warnings in the prescribing information of these two RSV vaccines, should be prioritized and investigated thoroughly. Furthermore, ongoing vaccine surveillance and further evaluation, particularly among immunocompromised patients, frail elderly subjects, and young infants that were under- or not represented in pivotal clinical trials, are necessary. As in the success story of combined pediatric vaccines, combination vaccines, conferring protection against several respiratory illnesses in one dose, could help improve vaccine acceptance and coverage rates in older adults. Full article

Background/Objectives: Respiratory syncytial virus (RSV) is a leading cause of respiratory infections in children. A novel RSVpreF vaccine for use among pregnant women for the prevention of RSV in infants is expected to be licensed in Mexico. Hence, the clinical and economic burden of RSV among infants in Mexico, with and without a year-round RSVpreF maternal vaccination program, was estimated. Methods: A cohort model was developed to project clinical and economic outcomes of RSV from birth to 1 year of age for maternal vaccination and no intervention. Incremental cost-effectiveness ratios were calculated from direct cost outcomes, life years, and quality-adjusted life years (QALYs). The value per dose of the RSVpreF for which the program would be cost-effective was explored. Analyses were conducted from the healthcare system perspective, with direct costs (2024 Mexican Pesos [MXN]) and outcomes discounted at 5% annually; scenario and sensitivity analyses tested the robustness of model settings and inputs. Results: Compared to no intervention, a year-round RSVpreF vaccine administered to 1891 M pregnant women would prevent 15,768 hospitalizations, 5505 emergency department cases, and 5505 physician office visits annually, averting MXN 1754 M in direct medical costs with an increase of 3402 life years or 3666 QALYs. The RSVpreF vaccine would be cost-saving up to MXN 1301/dose and cost-effective up to MXN 2105–MXN 3715/dose under an assumed cost-effectiveness threshold range of 1–3× the gross domestic product (GDP) per capita (MXN 247,310) per QALY gained. Conclusions: Year-round RSVpreF maternal vaccination would substantially reduce RSV’s clinical and economic burden among infants in Mexico and likely be a cost-effective program. Full article

Introduction: Vaccines are a significant public health achievement, which are crucial for child survival and disease control globally. In Brazil, the National Immunization Program (PNI) manages vaccination schedules, including essential vaccines like BCG and Hepatitis B, administered at birth. Despite achieving over 95% coverage for years, vaccination rates have declined since 2016, a trend exacerbated by the COVID-19 pandemic. This study aims to analyze spatial and temporal trends in BCG and Hepatitis B vaccination coverage at birth, identify areas with spatial variation in these trends, classify the identified trends, and investigate the pandemic’s impact on vaccination adherence. Methods: This is an ecological study with real-world data from Brazil, focusing on vaccination coverage from 2014 to 2023. Utilizing the Spatial Variation in Temporal Trends (SVTT) technique, the study identifies municipalities’ vaccination trends. It also employs time series analysis and Interrupted Time Series methods to evaluate the pandemic’s impact on vaccination rates, using data from the PNI and the Information System on Live Births (SINASC). Results: Between January 2014 and December 2023, Brazil administered 25,902,207 doses of the BCG vaccine to children at birth, with 3911 municipalities (70.24%) showing declining trends, particularly in Florianópolis. Similarly, 22,962,434 doses of the Hepatitis B vaccine were administered, with 3284 municipalities also experiencing declines. Conclusions: It is crucial that public health policies be reevaluated to address regional disparities in vaccination coverage, particularly in more vulnerable areas. Focused interventions, such as awareness campaigns, improved access to vaccination services, and strengthened monitoring, are fundamental to reversing this trend. Full article

In 2015, the 62nd session of the Regional Committee [RC] of the Eastern Mediterranean Region [EMR] endorsed the Eastern Mediterranean Vaccine Action Plan 2016–2020 (EMVAP) that included postponement of the measles elimination target to before 2020. However, the EMR does not have a regional rubella control or elimination goal. We reviewed the progress of measles and rubella surveillance in context of measles elimination in the Eastern Mediterranean Region during 2019–2022. We compiled data on coverage, reported cases, surveillance indicators, incidence, and genotypes. We conducted an age-cohort analysis to estimate the size of the susceptible population using coverage and SIAs coverage data. We reviewed the dossiers of countries that applied to the Regional Verification Commission [RVC] for the verification of measles and rubella elimination. Between 2019 and 2022, the regional coverage of the vaccine against measles and rubella was stable at 83% for the first dose [MCV1] and increased from 75% to 78% for the second dose [MCV2] after a dip during COVID-19. In the EMRO, eighteen countries are using MR (measles–rubella) and/or measles–mumps–rubella (MMR) vaccines and four are using measles vaccines. The reported regional measles incidence per 1,000,000 was 23.3 in 2019, decreased to 7.4 in 2020, and re-increased to 50 in 2022, with two main genotypes–D8 and B3–in circulation. Both genotypes are considered to be actively circulating in eighteen countries, with different circulating variants of each genotype. There were no genotyping data available from four countries. Measles and rubella surveillance indicators deteriorated in the region. The number of susceptible individuals exceeded one birth cohort in nine of the 22 countries. In 2019–2022, Bahrain, Egypt, Iran, and Oman were verified to have eliminated measles and rubella. While four countries eliminated measles and rubella and another five progressed toward measles and rubella elimination, however, immunity gaps and reported incidence increased in eleven countries. Countries approaching elimination need to prepare verification dossiers, while others need to increase their routine coverage, conduct follow-up campaigns, and improve surveillance. Submission of progress reports to the RVC will measure progress toward the goal. Full article

(1) Background/Objectives: Two pneumococcal conjugate vaccines, 15-(PCV15) and 20-(PCV20) valent formulations, are routinely recommended for US children in a 3+1 schedule. The first three doses are administered during the first year of life at 2, 4, and 6 months, while a booster dose is given at 12 to 15 months. This study evaluated the health and economic effects of the PCV20 infant series within the first year of life compared to PCV15. (2) Methods: Using a decision-analytic model, we calculated the health and economic effects of introducing PCV15 or PCV20 for five subsequent birth cohorts. Epidemiological data were drawn from peer-reviewed studies and estimates for vaccine effectiveness were extrapolated from established PCV13 effectiveness and PCV7 efficacy studies. Direct medical costs related to the disease treatment were extracted from the literature and inflated to 2024 dollars. (3) Results: Over the course of five years, the implementation of PCV20 vaccination for newborns in the United States, compared to PCV15, is projected to prevent an additional 220 cases of invasive pneumococcal disease, 6542 cases of community-acquired pneumonia, and 112,095 cases of otitis media within the first year of life across five subsequent birth cohorts. This strategy could prevent 66 infant deaths linked to these illnesses and confer extra health gains, amounting to 5058 years of life and 5037 quality-adjusted life years. These prevented cases are estimated to save approximately USD 147 million over 5 years. (4) Conclusions: This study demonstrated that vaccinating with PCV20 during the first 12 months of life compared to PCV15 in the US would yield a substantially greater health and economic return due to the five additional serotypes covered by PCV20. Full article

This study aimed to evaluate the cost-effectiveness of routine childhood immunization with the 20-valent pneumococcal conjugate vaccine (PCV20) in a four-dose regimen (3 + 1 schedule) versus the 15-valent PCV (PCV15/V114) in a three-dose regimen (2 + 1) in Germany. The study utilized a decision-analytic Markov model to estimate lifetime costs and effectiveness outcomes for a single birth cohort in Germany. The model tracked the incidence of acute pneumococcal infections and long-term pneumococcal meningitis sequelae for both vaccination strategies. The vaccine effectiveness data were derived from published clinical trials and observational studies of PCV7 and PCV13. Indirect effects, such as herd protection and serotype replacement, were included in the model. The model adopted a societal perspective, including direct medical, direct non-medical, and indirect costs. Scenario and sensitivity analyses were performed. In the base case, PCV20 prevented more pneumococcal disease cases and deaths, with an expected gain of 96 quality-adjusted life years (QALYs) compared to V114. However, PCV20 was associated with a total incremental cost of EUR 48,358,424, resulting in an incremental cost-effectiveness ratio (ICER) of EUR 503,620/QALY. Most of the scenario and sensitivity analyses estimated that the ICER for PCV20 exceeded EUR 150,000/QALY. Routine childhood immunization with PCV20 instead of V114 may not be an economically efficient use of healthcare resources in Germany. Full article

Measles is a highly contagious disease and remains a major cause of child mortality worldwide. While measles vaccine is highly effective, high levels of population immunity are needed to prevent outbreaks. Simple but accurate tools are needed to estimate the profile of population measles immunity by age to identify and fill immunity gaps caused by low levels of vaccination coverage. The measles immunity profile estimates and visualizes the percentage of each birth cohort immune or susceptible to measles based on measles vaccination coverage. Several tools that employed this approach have been developed in the past, including informal unpublished versions. However, these tools used varying assumptions and produced inconsistent results. We updated the measles population immunity profile methodology to standardize and better document the assumptions and methods; provide timely estimates of measles population immunity; and facilitate prompt actions to close immunity gaps and prevent outbreaks. We recommend assuming that the second dose of the measles-containing vaccine (MCV2) and doses given during supplementary immunization activities (SIAs) first reach children who have been previously vaccinated against measles, so that previously unvaccinated children are reached only when the coverage of MCV2 or SIA is higher than the coverage achieved by all previous measles vaccination opportunities. This updated method provides a conservative estimate of immunization program impact to assess measles outbreak risk and to facilitate early planning of timely preventive SIAs to close population immunity gaps. Full article

Despite considerable global efforts to enhance vaccine distribution in low-income countries, a significant number of children remain unvaccinated, particularly in Ethiopia. The underlying socioeconomic challenges in these regions are recognized as primary contributors to the low vaccination rates. However, the reasons for this persistent disparity in Ethiopia’s remote and underserved regions need further analysis. The study employed a cross-sectional design and was conducted as part of the Project HOPE Zero-Dose Evaluation from 1 February to 31 July 2022. Concentration indices were utilized to quantify the extent of inequality, with further decomposition aimed at identifying contributing factors to this disparity. The findings underscored that populations with lower socioeconomic status encounter high numbers of children receiving no vaccinations. Key factors influencing the number of zero-dose children included distance from healthcare facilities (61.03%), economic status of the household (38.93%), absence of skilled birth assistance (20.36%), underutilization of antenatal care services (<four visits; 8.66%), lack of postnatal care (8.62%), and rural residency (7.69%). To reduce the number of zero-dose children in Ethiopia, it is essential to implement context-specific strategies that address socioeconomic barriers and integrate innovative approaches with community engagement. This approach will help to ensure equitable access to vaccines for children across all socioeconomic statuses. Full article