Vaccine: X

Background: In Burkina Faso, typhoid fever remains a major public health concern, with a high incidence among children younger than 15 years of age. To address this burden, the country introduced typhoid conjugate vaccine in January 2025 through a national vaccination campaign reaching children aged 9 months to 14 years. This study aimed to estimate the cost of typhoid conjugate vaccine delivery during the national campaign and to identify the main cost drivers across different administrative levels. Methods: We conducted a cross-sectional, retrospective costing study using a microcosting approach from the government perspective. We collected data from fifty health facilities, eight health districts, five health regions, and the national level. Financial and economic costs were estimated for each level, excluding vaccine and syringe costs. All costs were converted to 2024 USD using the official exchange rate. Findings: Vaccinators administered a total of 10.5 million typhoid conjugate vaccine doses. The average financial cost per dose was $0.47 (95% CI: $0.39-$0.51), and the economic cost was $2.16 (95% CI: $1.71-$2.56). Human resources and per diem payments were the main contributors to costs. Costs varied by geography, delivery strategy, and security context, with higher costs observed in rural and conflict-affected areas. The mobile-temporary posts strategy had the highest economic cost per dose ($2.02; 95% CI: $1.64-$2.40), while the fixed strategy had the highest financial cost per dose ($0.41; 95% CI: ($0.32-$0.49). Conclusion: The financial cost per dose remained within Gavi, the Vaccine Alliance's operational support range. The observed cost variations highlight the need for targeted funding and enhanced logistical support to ensure equitable access, particularly in rural and insecure areas. This study provides evidence to inform future vaccination campaigns and supports decision-making for typhoid conjugate vaccine introduction in other countries in the region.

Aim: To explore RSV knowledge and awareness, RSV vaccination perceptions and acceptability, and preferences for maternal vaccine delivery and communication amongst pregnant women and mothers of infants and toddlers in England. Methods: Between July and November 2024, semi-structured qualitative interviews were performed with 30 mothers (youngest child under 2 years), two of whom were pregnant with a subsequent child. The study was conducted as a follow-on to a UK Health Security Agency survey of attitudes towards RSV vaccination amongst pregnant and post-partum women in England. Findings: Although most mothers had heard of RSV, mothers with experience in health roles were more likely to understand the potential severity of RSV in infants. Likelihood of maternal RSV acceptance was reported as high, with most mothers considering RSV vaccination as beneficial in protecting infants. Most mothers preferred a hybrid approach to vaccine communication, with information available online (e.g. through the NHS website), via written sources (e.g. NHS produced leaflet), and through talking with midwives. For convenience, most mothers preferred the option of fitting vaccinations within the antenatal midwifery appointment schedule rather than going to general practice for a separate appointment. Conclusion: To support maternal RSV vaccination decision-making and access, women need vaccine information early in pregnancy; information provision through a range of different sources (i.e. online, paper, in-person); and vaccination delivery in a convenient location (i.e. as part of antenatal appointments).

ObjectiveThis study aimed to assess the effectiveness of SMS and voice message reminders in reducing the dropout rate in Lome-Togo, in 2026. MethodsWe conducted a cross-sectional study between October 2025 and March 2026 in the Grand Lome region. The intervention consisted of an integrated digital system used by health facilities to send automated SMS. Categorical variables were described in terms of frequency and proportion; Fishers exact test was used to compare proportions. Quantitative variables were described by their means accompanied by their standard deviation; the Wilcoxon rank-sum test was used to compare means. The significance level for statistical tests was set at 5%. ResultsA total of 30 health facilities were included. Seventy percent (70.0%) of the health facilities used messages associated with calls. Ninety percent (90.0%) of participants found the reminders useful, and 60.0% reported an improvement in Expanded Program on Immunization services related to their use. Among participants who received a reminder, 51.0% kept their vaccination appointments. The Penta 1/3 dropout rate decreased from 3.2% before the intervention to 1.3% (p < 0.001). Among the 323 parents of children included, only 20.74% reported receiving a reminder by phone. Sixty-point-five percent (60.5%) preferred to receive both text messages and voice calls. ConclusionThis study demonstrates the operational feasibility of an SMS/call-based reminder system in reducing dropout rate for childhood vaccination in Togo.

IntroductionThe COVID-19 pandemic disrupted immunization services in Togo, resulting in 69,672 "zero-dose" and 24,846 "under-vaccinated" children by the end of 2023. This study assessed the effectiveness, acceptability, and feasibility of a social marketing approach deployed during the 2025 Big Catch-Up initiative in Togo. MethodsA convergent mixed-methods study was conducted in 17 priority health districts. The quantitative component compared vaccination coverage before and after the intervention using administrative data. Chi-squared test for linear trend compared district-level coverages, and statistical significance was set at p<0.05 for all tests. The qualitative component used in-depth interviews with key informants to collect data, followed by thematic content analysis. The intervention was grounded on the social marketing framework with 4 pillars (4Ps): Product, Price, Place, and Promotion. ResultsCoverage increased dramatically: Penta1 from 1% to 64%, Penta3 from 1% to 45%, MR1 from 4% to 50%, and MR2 from 6% to 49% (all p<0.001). Togo ranked 3rd out of 24 African countries for Penta1 progress. The approach demonstrated high community acceptability, with Vaccination Monitoring Committees praised as being culturally appropriate. Key concerns included sustainability and resource constraints. ConclusionSocial marketing proved to be effective for increased community adherence and immunization coverage improvement. However, long-term sustainability requires institutionalization of community structures with domestic funding and continued health system strengthening.

BackgroundPost-market vaccine safety surveillance and research are essential to detect and evaluate rare adverse events following immunization (AEFIs) not identified in pre-licensure clinical trials, such as myocarditis post-COVID-19 vaccination. AEFI surveillance infrastructure varies between jurisdictions. Factors that enable or hinder AEFI investigation across diverse settings are not well understood. ObjectiveTo examine clinical, social, and structural/system factors that enable AEFI case identification, reporting, data and biosample collection in high-income countries (HICs) and low-and middle-income countries (LMICs). MethodsWe conducted a qualitative study informed by Interpretive Description in Kenya, South Africa, and Canada. Participants were recruited using purposive and snowball sampling from three groups: (1) key informants with leadership roles in AEFI surveillance and research, (2) healthcare workers, research and laboratory staff involved in AEFI investigation and research, and (3) past participants in vaccine studies. Data were collected through semi-structured interviews and focus group discussions. Thematic analysis was conducted. ResultsEighteen key informants, 47 healthcare workers and research staff, and 27 past research participants were enrolled. Facilitators and barriers were identified across two domains: AEFI surveillance and investigation, and vaccine safety research participation. AEFI surveillance and investigation were shaped by trust in system responsiveness, beliefs and awareness around AEFI reporting, digital innovation, and implementation gaps. Research participation was shaped by altruism and social influence, logistics and research infrastructure, and institutional policies and privacy. Facilitators to AEFI surveillance and research included established policies and procedures for AEFI surveillance, digital tools, emphatic communication, and convenient research processes. Barriers included limitations in workforce capacity, diagnostic testing and funding (especially in LMICs), and cumbersome research approval processes. ConclusionsFindings underscore the need for both globally harmonized standards and locally tailored strategies to support vaccine safety surveillance and research in LMICs and HICs that are patient/participant-centered and include sustainable investments in infrastructure and workforce capacity.

Influenza A virus can cause severe complications in pregnant women and infants, yet no influenza vaccines are approved for infants younger than six months. To address this, novel maternal vaccination strategies are needed to increase global access and coverage in these vulnerable populations. This study evaluated a hemagglutinin (HA) A/California/2009 (H1N1)-based human adenovirus 5 (huAd5) vector vaccine, adjuvanted with a TLR3 agonist, for its ability to induce influenza-specific passive immunity from pregnant and lactating pigs to their piglets following different immunization routes. Influenza naive pregnant dams were vaccinated via oral, intranasal (IN), or intramuscular (IM) routes three weeks prepartum and boosted four weeks later. Serum, colostrum and milk samples were collected longitudinally to assess HA-specific antibody induced by vaccination. H1N1-Ca/09 neutralizing antibodies were evaluated in serum and IFN{gamma} producing cells were assessed in blood, spleen and lymph node cells. IN and IM routes elicited robust serum HA-specific antibody responses when compared to control animals at one- and four-weeks post-boost, whereas the oral route resulted in poor antibody induction across all samples tested. Piglets nursing from IN and IM vaccinated dams showed a significantly higher level of HA-specific antibodies in serum at 2-3 weeks post-partum compared to control piglets. Notably, IN immunized dams and their piglets showed significantly elevated influenza neutralizing antibodies compared to controls. This work demonstrated that both IN and IM immunization with a huAd5-vectored vaccine robustly induced maternal influenza-specific immunity that supported passive transfer to nursing piglets, with IN immunization resulting in superior transfer of neutralizing antibodies.

Protracted conflict in Sudan since April 2023 has severely disrupted routine immunization services, particularly in the Darfur region, resulting in widespread vaccine stockouts, declining coverage, and increased risk of vaccine-preventable disease outbreaks. Traditional national supply routes became largely inaccessible, exacerbating inequities in immunization access for conflict-affected and displaced populations. This paper examines the design, implementation, and outcomes of a cross-border vaccine deployment strategy implemented in 2025 through Chad to restore vaccine availability in Darfur. Using programmatic data, shipment records, coverage reports, and partner monitoring outputs, the study assessed the operational feasibility, partnership arrangements, and public health impact of the intervention on routine immunization and outbreak response. In 2025, nearly 20 million doses of vaccines were successfully delivered to the five Darfur states through cross-border operations, supporting routine immunization services and outbreak response campaigns. Average coverage for the first dose of a DPT-containing vaccine (DPT1) increased from 22.6% in 2024 to 83.2% in 2025, while DPT3 and MCV1 coverage rose to 55.4% and 50.4%, respectively. Oral cholera vaccine campaigns achieved 90.4% coverage among targeted populations, and polio outbreak response campaigns exceeded 100% administrative coverage, reflecting both successful reach and uncertainties in target population estimates due to population displacement. Investments in cold chain infrastructure and strengthened coordination among government, UNICEF, Gavi, and implementing partners were critical to these outcomes. The findings demonstrate that cross-border vaccine deployment can serve as a viable and effective mechanism for restoring immunization availability and support recovery of immunization service delivery in a highly constrained conflict setting. While not a substitute for functional national systems, such approaches are essential life-saving interventions during acute crises and should be integrated into preparedness planning for fragile and conflict-affected contexts.

Dengue disease remains a significant global health threat, with current vaccines exhibiting variable efficacy and safety concerns. Virus-like particles (VLPs) offer a promising alternative by mimicking native virus structures without infectious genomes. We engineered a mammalian expression plasmid encoding Dengue-1 prM and E proteins, optimized for secretion using Japanese Encephalitis virus signal sequences, and transiently expressed it in HeLa cells. Purified VLPs exhibited spherical morphology ([~]39 nm diameter) consistent with native virions, as confirmed by transmission electron microscopy. Immunization of mice with these VLPs elicited robust Dengue-1 specific IgG antibody responses. Our study demonstrates production of immunogenic Dengue-1 VLPs in HeLa cells, highlighting their potential as a vaccine candidate and a tool for serodiagnosis. Further characterization of VLP epitopes and protective efficacy is warranted to advance vaccine development. ImportanceDengue remains a significant global health challenge, with serotype 1 being one of the dominant strains causing recurrent outbreaks in Nepal. Existing vaccines demonstrate limited efficacy and pose significant safety concerns, particularly in seronegative populations. To address these limitations, this study explores virus-like particles (VLPs) as a safer alternative vaccine platform. VLPs elicit robust immunogenicity by mimicking the structure of native virus while completely lacking genetic components. This study combines DENV1 structural proteins with optimized expression systems to enhance immunogenicity. This work is particularly significant as the first dengue vaccine research conducted in Nepal, directly addressing antigenic mismatches between existing commercial vaccines and locally circulating viral strains. Furthermore, the study provides scalable platform for developing region-specific dengue vaccines for other serotypes and flaviviruses.

IntroductionChildhood immunization is highly cost-effective, yet uptake is shaped by sociocultural and religious influences. In Bauchi State, Nigeria, coverage remains low (Penta3 58.2%; fully vaccinated according to the national schedule 22.5% among children aged 12-23 months; Nigeria Demographic and Health Survey (NDHS) 2024). Religious leaders shape community norms, but their perspectives on immunization in Bauchi are not well characterized. Guided by Omans model of religion/spirituality and health, we explored religious leaders knowledge, beliefs, attitudes, practices and recommendations regarding childhood immunization. MethodsBetween December 2022 and January 2023, semi-structured interviews were conducted with 22 religious leaders purposively sampled across Bauchi State (geographically stratified by local government area). Sampling continued until thematic saturation. Interviews were conducted in Hausa or English, audio-recorded, translated into English where necessary and transcribed. Data were analyzed using Braun and Clarkes thematic analysis in ATLAS.ti. Ethical approval was obtained from the Bauchi State Health Research Ethics Committee, and participants provided verbal informed consent. ResultsMost leaders described immunization as preventive and compatible with religious teachings and reported that observed child health benefits reinforced support. Many described shifts from earlier skepticism to endorsement after lived experience and religious and scientific explanation, while noting persistent misinformation, particularly fertility-related and "population control" narratives. Leaders described three recurring influence practices: Visible role modelling, sermon-based messaging aligned with scripture, and community mobilization through religious gatherings and support during outreach activities. Leaders emphasized that respectful health worker engagement and reliable service delivery were perceived to strengthen trust and support community uptake. ConclusionReligious leaders in Bauchi State may be strategic partners for improving vaccine acceptance. However, this leader-level qualitative study did not measure congregant outcomes. Programs should consider structured engagement with religious leaders, strengthen bidirectional rumor tracking and response, and support frontline health workers to strengthen trust and demand for routine and outreach immunization services, pending evaluation. Future work should include dissenting and more diverse leaders and link engagement to measurable outcomes. SUMMARY BOXO_ST_ABSWhat is already known on this topicC_ST_ABSO_LIChildhood immunization coverage remains low in northern Nigeria, including Bauchi State, and both demand- and supply-side barriers contribute to under-vaccination C_LIO_LIReligious leaders can influence health behaviors and have been engaged in immunization efforts, but their perspectives and practical roles are not consistently described for Bauchi State C_LI What this study addsO_LIMost interviewed religious leaders viewed childhood immunization as preventive and compatible with religious teachings, and many described actively supporting immunization after engagement with immunization programs C_LIO_LILeaders reported persistent community concerns and misinformation, including fertility-related rumors, alongside service delivery constraints such as distance, waiting times, and staff attitudes C_LIO_LILeaders described mobilization practices, including sermon messaging, role modelling, and outreach-related community engagement, and proposed practical program improvements, including house-to-house service delivery and coordination between immunization teams and local religious leaders C_LI How this study might affect research, practice and policyO_LIImmunization programs may benefit from structured partnerships with religious leaders, including timely, credible information and co-developed messaging to address misconceptions C_LIO_LIImprovements in service accessibility and respectful care should accompany demand-generation to maximize impact C_LI

Background: The COVID-19 pandemic disrupted childhood immunization programmes in many countries worldwide. However, evidence on its impact in low and middle-income countries remains limited. This study examined the impact of the COVID-19 pandemic on childhood immunization coverage across 514 districts in Indonesia and identified district-level associated factors. Methods: We conducted a nationwide longitudinal analysis of the Expanded Programme on Immunization to compare immunization coverage before and after the pandemic. The outcome variable was the annual childhood immunization coverage (proportion of children aged 0-12 months who have received all recommended doses of childhood immunization as per the national immunization schedule). The explanatory variables include COVID-19 burden and vaccination rates, health system and human development indicators. Mixed-effect logistic regression was done to assess association between the explanatory and outcome variables. Results: At the national level, the coverage was 83.2% in pre-pandemic, 75.0% in the first year of pandemic, and 88.6%, in the second. In the first year, 69.3% of districts experienced significant decline, with a lower national coverage ratio of 0.92 (95% confidence interval 0.89-0.94). In the second year, 36.2% districts were still affected. The multivariable analysis showed that a significant decline in coverage during the first pandemic year was associated with high COVID-19 incidence (adjusted odds ratio 2.19, 95%CI 1.01-4.73 for the highest vs. lowest group), low midwife adequacy (5.84, 2.40-14.16 for the lowest vs. the highest group, 2.61, 1.26-5.40 for low-middle vs. the highest group), and a high proportion of health facility-based births (2.98, 1.49-5.98 for middle-high vs. the lowest group). Conclusions: The COVID-19 pandemic negatively and unevenly impacted childhood immunization in Indonesia, with greatest impacts in districts facing a higher COVID-19 burden and weaker health system capacity. These findings underscore the need for targeted efforts to strengthen the local health system for future health crises. Keywords: COVID-19, pandemic, immunization, vaccine preventable diseases

Background Vaccine-preventable diseases (VPDs) continue to impose a significant health and economic burden globally, despite advances in immunization programs. Narrower to the context of Saudi Arabia, the current literature consistently shows that the high vaccination coverage has had the primary impact of reducing disease incidence. Regardless, the broader economic impact of VPDs and the financial benefits of immunization remain important for policy evaluation within Saudi Arabia. Methods This study employed a model-based economic evaluation using a societal perspective in order to carry out an estimation of the economic burden of measles, influenza, and pneumococcal diseases. We utilized the Cost of Illness (COI) approach for the purpose of quantifying direct medical costs and indirect productivity losses. On the other hand, the Value of Statistical Life (VSL) approach helped in the estimation of the monetary value of mortality reduction. A comparative framework analyzed current vaccination coverage against a counterfactual no-vaccination scenario for the calculation of the return on investment (ROI). Results The estimated annual economic burden of the three selected VPDs in the absence of vaccination was USD 385 (95% CI: 315-460) million. Immunization programs generated substantial economic benefits, with total benefits estimated at USD 1085 (95% CI: 815-1360) million annually. The calculated ROI was 9.0 (95% CI: 6.8-11.3), essentially an indication that for each dollar invested in vaccination, there was multiple economic returns yielded. Sensitivity analyses confirmed the robustness of these findings. Conclusion Immunization programs in Saudi Arabia provide significant economic and public health benefits and for this reason, sustained investment in vaccination is fundamentally essential towards the reduction of disease burden, improve population health, and ultimately support long-term economic productivity.

BackgroundOlder adults face a disproportionately high risk of severe influenza, yet the standard inactivated vaccine (IIV) offers suboptimal protection in this population. This study evaluates the cost-effectiveness of replacing IIV with the recombinant influenza vaccine (RIV) for adults aged [&ge;]50, [&ge;]65, and [&ge;]80 years in Hong Kong. MethodsA decision tree model was used to compare RIV with IIV for adults aged [&ge;]50, [&ge;]65, and [&ge;]80 years in Hong Kong, from a societal perspective. Costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios (ICERs) were evaluated with the impact of parameter uncertainty on the results assessed via deterministic and probabilistic sensitivity analyses. ResultsFor adults [&ge;]50 years, RIV increased total costs by USD5.1 (HKD39.8) per person and gained 0.00012 QALYs (ICER: USD40,659 [HKD317,140] per QALY) compared to IIV. Among adults [&ge;]65 years, RIV cost USD6.0 (HKD46.8) more and gained 0.00021 QALYs (ICER: USD29,077 [HKD226,801] per QALY). For adults [&ge;]80 years, RIV cost USD3.2 (HKD25.0) more and gained 0.00015 QALYs (ICER: USD21,092 [HKD164,518] per QALY). ICERs were less than willingness-to-pay thresholds of one to three times Hong Kongs gross domestic product per capita. ConclusionsRIV is cost-effective compared with IIV for adults [&ge;]50, [&ge;]65, and [&ge;]80 years in Hong Kong, with the lowest ICER observed in individuals [&ge;]80 years.

Background Ever since the COVID-19 vaccine became available, vaccinations in adolescents lagged behind adults. Whether adolescent vaccination rates were higher in states with "Minor Consent" policies remains unknown. Methods We accessed adolescent (aged 12-17) county-level vaccine administration data from the CDC (12/2020-05/2023). Our outcomes were COVID-19 vaccination counts for: 1) initial dose, 2) completed series doses, and 3) booster doses. Panel Poisson regression models with state and time random effects, seasonal fixed effects, log-population offsets, and adult vaccination rates were estimated to calculate incidence rate ratios (IRR), testing the association between residing in a state with a Minor Consent policy and COVID-19 vaccine uptake. Results Overall, for the initial dose and complete series, there was no difference in adolescent COVID-19 vaccination between states with or without Minor Consent policies. However, we found that Minor Consent policies were associated with lower COVID-19 booster doses (IRR = 0.582; 95% CI: 0.409, 0.828; p = 0.0026). This association was not found in urban counties (IRR = 0.867; CI = 0.722, 1.043; p = 0.1295), but only in rural counties (IRR = 0.541; CI = 0.401, 0.730; p < 0.0001). Conclusions Minor Consent policies were not associated with higher adolescent COVID-19 vaccination. Rather, we found that Minor Consent policies were associated with lower adolescent vaccination for booster doses in rural counties. Despite minimal evidence of impact, states continue to implement Minor Consent vaccination policies. Future research should investigate not just other vaccines, but also how Minor Consent policies impact parental trust in public health more broadly.

BackgroundReliable estimates of immunization delivery costs are essential for planning, budgeting, and economic evaluation of vaccination programs. Although a number of empirical costing studies have been conducted in recent years, many low- and middle-income countries (LMICs) continue to lack up-to-date, accurate delivery unit cost estimates--particularly for adolescent and campaign vaccination strategies. Building on prior work, this study aimed to produce updated, standardized country-level estimates of immunization delivery unit costs for different vaccination modalities across all LMICs. MethodsUsing data on study-level unit cost estimates reported by empirical costing studies in the 2024 update of the Immunization Delivery Cost Catalogue, we fitted Bayesian meta-regression models predicting per-dose delivery costs for routine childhood vaccination, routine adolescent vaccination (using human papillomavirus vaccination as a proxy), and vaccination delivered via mass campaigns. Regression models incorporated country-level covariates (per-capita gross domestic product, population size, third-dose diphtheria-tetanus-pertussis vaccination coverage, urbanization, population density, and under-five mortality) and study-level characteristics (cost category, financial versus economic costing perspective, and full versus incremental costing methodology). Fitted models were used to generate country-specific and population-weighted average economic and financial cost per dose estimates for 2024, in 2024 US dollars. ResultsThe analysis included 142 observations for routine childhood vaccination, 63 observations for routine adolescent vaccination, and 113 observations for campaign vaccination. For 2024, the population-weighted mean economic cost per dose across all LMICs was estimated at $5.86 (95% uncertainty interval: $2.74-13.43) for routine childhood vaccination, $17.65 ($7.76-44.30) for routine adolescent vaccination, and $3.13 ($2.03-4.78) for campaign vaccination. Corresponding financial costs per dose were $3.02 ($1.52-6.29), $10.08 ($4.15-25.01), and $1.79 ($1.11-2.91), respectively. Substantial heterogeneity in delivery costs was observed across countries, delivery modalities, and cost perspectives. The estimated associations between predictors and unit costs may be influenced by unobserved study characteristics, and therefore should be interpreted as correlational rather than causal. ConclusionsBy leveraging an expanded empirical evidence base and a Bayesian meta-regression framework, this study provides updated per-dose delivery costs for routine childhood vaccination and estimates new per-dose delivery costs for routine adolescent vaccination and campaign vaccination. As policy decisions often must be made despite incomplete information, these estimates provide a practical source of evidence to support analyses when direct cost data are unavailable.

Background: The value proposition for Shigella vaccines is strengthened by the potential for vaccines to prevent linear growth faltering. However, because expected effect sizes in Phase 3 vaccine trials are small due to limited Shigella incidence, a simple comparison of growth by randomized vaccine arm is likely underpowered and may yield null or even inverse results. Methods: We consider a new approach that estimates vaccine effects in the subgroup that would be infected in absence of vaccination, termed the naturally infected. In simulations parameterized by multi-site studies of diarrhea, we compare power for detecting linear growth effects in the naturally infected versus the full study. We further quantified how power is impacted by trial design choices including immunization schedule, study site, and timing of growth measurements. Findings: Simple comparisons of height-for-age z-score (HAZ) by randomized vaccine arm have extremely limited power (<15%) at realistic trial sizes (n=2,500 to 20,000) and carry risk of showing an inverse effect due to random chance. In contrast, naturally infected effects were five to ten times larger and power was up to three times higher. Using a twelve month immunization schedule with a single growth endpoint in high-incidence settings maximized power to detect an effect. Interpretations: While realistically sized clinical trials may be underpowered to detect an effect of vaccination on growth, estimation using the naturally infected subpopulation and careful trial design improve chances of detecting an effect while mitigating risks of null or inverse results.

Cameroon introduced Human papilloma virus vaccine (HPVV) into the routine immunization schedule in October 2020. By the end of 2022, coverage remained low. To increase coverage, Cameroon switched to a country-wide, gender-neutral vaccination (GNV) approach in 2023, coupled with a revamped delivery strategy consisting of Community Dialogues (CDs) and Periodic Intensification of Routine Immunization (PIRIs) activities in selected health districts (HDs). We assessed the impact of these programmatic changes, notably the GNV approach, on HPVV coverage. This retrospective, cross-sectional study measured the effect of GNV and CDs + PIRIs on HPVV coverage among 9-year-old girls in Cameroon (2022-2023). Data on HPVV coverage from all 203 HDs were extracted from DHIS2, and coverage was calculated at the HD level, based on the estimated population eligible of 9-year-old girls. Descriptive statistics and multiple regression models were employed to assess the impact of GNV on vaccination coverage while adjusting for CDs + PIRIs and urban/rural status. In 2023, of the 203 HDs, 115 (56.7%) conducted GNV only, 74 (36.5%) implemented GNV & CDs + PIRIs, and 75.9% (154) were classified as rural. Among age-eligible girls, there was an overall increase in HPV vaccination coverage, with coverage rising 39.2 percentage points from 2022 to 2023. Following multiple linear regression, there was a significant increase in HPVV coverage in HDs with GNV & CDs + PIRIs compared to those with no GNV and no CDs + PIRIs ({beta}:55.5%, 95%CI: 38.7, 72.3, p=0.000). Furthermore, there was a significant increase in HPVV coverage in HDs with GNV only compared to those with no GNV or no CDs + PIRIs ({beta}:28.7%, 95%CI: 12.5, 45.0 p=0.001). Overall, the GNV approach increased HPVV coverage for girls significantly, particularly when implemented alongside CDs + PIRIs.

Background To anticipate the impact of new pneumococcal vaccines and guide future updates, accurate forecasts of changes in non-vaccine serotypes (NVTs) are needed. We developed and evaluated three models that incorporated different assumptions about the way in which NVTs will increase and generated ensemble predictions for the frequency of NVTs in different post- pneumococcal conjugate vaccines (PCV) periods. Methods We analyzed age- and serotype-specific invasive pneumococcal disease (IPD) cases from the United States CDCs Active Bacterial Core surveillance during the pre-PCV (1998-1999), early post-PCV7 (2000-2004), late post-PCV7/pre-PCV13 (2005-2009), early post-PCV13 (2010-2014), and late post-PCV13 (2015-2019) periods. These data were augmented with IPD cases from several countries and combined with serotype-specific invasiveness to infer serotype-specific carriage prevalence. Three models (Ranking, Proportionate, NFDS-lite) generated independent predictions of post-PCV IPD frequencies, which were integrated using an accuracy-weighted ensemble. Model performance was evaluated using the normalized root mean square error (NRMSE). Results A total of 23,959 non-PCV7 and 15,580 non-PCV13 cases were analyzed. NVT cases increased from the pre-PCV7 to the late post-PCV7 and post-PCV13 periods. The accuracy of predictions across age groups and models was consistent and high during the post-PCV13 periods but varied during the post-PCV7 periods. The Proportionate model (NRMSE=0.70-3.95) outperformed the NFDS-lite (NRMSE=0.93-8.91) and Ranking (NRMSE=1.51-5.37) models during the early-post-PCV7 period, whereas the NFDS-lite model (NRMSE=1.55-9.82) was superior to the Proportionate (NRMSE=1.45-10.22) and Ranking (NRMSE=1.86-11.35) models during the late post-PCV7 period. The Ensemble model improved on these individual models. Conclusions The Ensemble model offers a tool for forecasting serotype patterns to inform pneumococcal vaccines impact and future pneumococcal vaccine formulation.

BackgroundNeisseria gonorrhoeae poses significant public health challenges due to multidrug-resistant gonorrhoeic and severe reproductive health complications of untreated infection. No vaccine is licensed to prevent gonorrhea. However, the meningococcal outer membrane vesicle (OMV)-containing vaccine, 4CMenB, provides moderate cross-protection against gonorrhea. We have recently demonstrated that immunization with gonococcal OMV accelerates clearance of gonococcal infection in mice compared with 4CMenB. MethodsTo gain insight into possible mechanisms of protection of gonococcal OMV, we evaluated the immunogenicity of GonoVac, a candidate native OMV (nOMV) vaccine against gonorrhea, in mice and rabbits. Three doses of GonoVac were administered intramuscularly from 0.15 to 5 {micro}g in mice, and four doses were used to immunize rabbits at 50 {micro}g per dose, formulated with or without aluminum hydroxide (Al(OH)3). Systemic and mucosal antibody responses were evaluated by enzyme-linked immunosorbent assay (ELISA) and serum bactericidal assay (SBA). Cellular responses were assessed by enzyme-linked immunosorbent spot (ELISpot). ResultsImmunization with GonoVac formulated with and without Al(OH)3 induced significantly higher levels of gonococcal serum and vaginal IgG, and serum bactericidal antibodies, compared with 4CMenB, which induced no serum killing activity. Serum bactericidal activity of GonoVac correlated with anti-gonococcal IgG and IgG2a levels. Serum IgA levels were minimal. Cellular immune responses were higher in mice receiving GonoVac/Al(OH)3 compared with GonoVac alone. Immunogenicity was similar for GonoVac produced in a bioreactor and shake flasks. ConclusionGonoVac elicits robust and functional immune responses in mice and rabbits compared with 4CMenB, supporting its further development as a promising candidate vaccine against gonorrhea. ImportanceGonorrhea, caused by Neisseria gonorrhoeae, remains a significant global health concern, disproportionately affecting populations in low- and middle-income countries (LMICs), particularly women. The emergence of multidrug-resistant strains of N. gonorrhoeae has raised the concern of untreatable gonorrhea, underscoring the urgent need for effective preventive measures. Although there is no licensed vaccine against gonorrhea, the meningococcal OMV-based vaccine, 4CMenB, is partially effective against the disease and has been recommended for use in high-risk groups. In this article, we build on previous findings of enhanced efficacy of gonococcal OMV vaccine candidates compared with 4CMenB in the mouse gonococcal infection model to demonstrate the superior anti-gonococcal immunogenicity of a gonococcal OMV-based candidate vaccine (GonoVac) compared with 4CMenB. GonoVac elicits robust immunity in mice, inducing antibodies that are able to kill gonococci, whereas 4CMenB does not. The findings highlight the potential of GonoVac as a promising vaccine candidate for the prevention of gonorrhea worldwide.

BackgroundVaccination is a cost-effective intervention preventing causes of 48% of deaths among children Under-5 in sub-Saharan Africa. However, one in five African children still has not completed basic vaccination, and over six million children have not received a single dose of the Diphtheria, Tetanus and Pertussis vaccine, resulting in over half a million deaths annually. This study aims to understand the key factors influencing pediatrics health (vaccination) decision-making in sub-Saharan Africa. MethodsA cross-sectional design using a multi-stage stratified sampling approach was used. Data were collected from 2,451 households with children Under-5 in three countries and analyzed using R. Correlation analysis was used to understand the associations between variables, while regression analysis was used to control for covariates and identify influences on one another. ResultsThe findings show that beliefs in gender disparity, misinformation, and masculinity can undermine childhood vaccination outcomes. A childs gender (r = -0.33-0.40, p < 0.01) and misinformation (r = -0.38-0.54, p < 0.01) impact vaccination intentions and behavior. Meanwhile, positive attitudes (r = 0.36-0.49, p < 0.01), trust (r = 0.17-0.34, p < 0.01) and peer influence (r = 0.27-0.33, p < 0.01) significantly improve uptake. However, regressions show that male caregivers had weaker attitudes ({beta} = -0.31, p < 0.001), stronger beliefs about misinformation ({beta} = 0.33, p < 0.001) and lower vaccination intentions ({beta} = -0.12, p < 0.001). Country comparisons reveal that Kenyan and Malawian children are 3.6 (OR = 3.64, p < 0.001) and 13 (OR = 13.13, p < 0.001) times more likely to be vaccinated than Nigerian children, respectively. Furthermore, masculinity had a significant effect on men, Muslims and polygamous households. ConclusionTo address low vaccination uptake in sub-Saharan Africa, context-sensitive strategies are required that incorporate gender norms, counter misinformation, and engage fathers.

Pneumonia remains a leading cause of global child mortality. Following the Pneumococcal Conjugate Vaccine (PCV) introduction in Yogyakarta, Indonesia, uptake for the primary series (PCV1 and PCV2) exceeded 90%. However, PCV3 coverage remained suboptimal (60% in 2023; 75% in 2024), indicating significant dropout. This study aimed to identify determinants of PCV immunization completeness and timeliness to address this gap. We conducted a cross-sectional study using cluster sampling among 405 caregivers of children aged 13-37 months in Yogyakarta City in March 2025. Data were collected via structured digital questionnaires assessing socio-demographics, perinatal conditions, knowledge, support systems, and attitudes toward multiple injections. Multivariate logistic regression was employed to determine factors associated with PCV immunization completeness and timeliness. Of 398 participants (98.3% response rate), the majority were female (95.7%) and housewives (75.1%). The prevalence of PCV completeness was 66.3%, while timeliness was only 36.4%. Multivariate analysis revealed that acceptance of multiple injections was the strongest predictor for both completeness (aOR 49.18; 95% CI: 21.30-113.50) and timeliness (aOR 22.04; 95% CI: 6.55-74.08). Additionally, home ownership (aOR 1.93; 95% CI: 1.04-3.58) was associated with completeness, whereas high knowledge (aOR 1.85; 95% CI: 1.12-3.03) improved timeliness. Conversely, preterm birth was significantly associated with lower odds of timeliness (aOR 0.29; 95% CI: 0.09-0.88). Acceptance of multiple injections emerged as the most critical modifiable factor for both outcomes. To optimize the PCV program, health authorities should prioritize counselling strategies to alleviate parental concerns regarding multiple injections. Additionally, intensified monitoring for preterm infants is crucial to mitigate immunization delays.