Vaccine: X

The Global Polio Eradication Initiative (GPEI) is known to be one of the most successful disease eradication initiatives with massive reductions in polio transmission as well as its contributions to strengthening health systems and capacity building. Existing analyses provide limited insight into how capacity was developed, which forms of capacity were strengthened or neglected, and how these efforts were experienced by implementers. Understanding these factors can be helpful as GPEI accelerates...

BackgroundThe 2013-2016 Ebola virus disease outbreak in West Africa profoundly affected Sierra Leones health financing, health delivery, health governance, and health workforce. The country becomes the first among those most severely affected ten years ago by the West Africa Ebola outbreak, to launch nationwide preventive Ebola vaccination, targeting 20,000 frontline workers who received a single dose of the Ebola Vaccine. MethodsA mixed-method study design that analysed administrative vaccinat...

BackgroundThe LP.8.1-containing COVID-19 mRNA vaccines were recommended for the 2025 seasonal vaccination campaigns in Europe and the United States. Safety data on these vaccines are limited. MethodsWe conducted a nationwide register-based cohort study in Denmark including all adults aged 65 years and older or at high risk of severe COVID-19 who had received previous COVID-19 vaccine doses. The study period was July 1, 2025, to December 3, 2025. We estimated incidence rate ratios using Poisson ...

Background and objectiveVietnam had increasing rates of zero-dose children and sub-optimal COVID-19 vaccine booster coverage in 2022. With the Vietnamese Ministry of Health, we co-designed, implemented and evaluated a vaccine education and communication program for health workers and community leaders to improve trust, knowledge, communication skills and intention to vaccinate for routine childhood and COVID-19 vaccines. MethodThe Train-the-Trainer Vaccine Champions program was piloted in 2022 ...

BackgroundTyphoid fever incidence estimates are central to policy decisions on vaccine introduction and investments in non-vaccine prevention and control but are often unavailable. We explored whether prevalence metrics from sentinel studies of community-onset bloodstream infections could accurately predict local Salmonella Typhi (S. Typhi) incidence. MethodsUsing a previous systematic review (January 2018-December 2024), we identified studies reporting both typhoid incidence and prevalence of ...

BackgroundVaccine hesitancy is a growing issue that the WHO ranks as one of the top 10 threats to global health. Public confidence in vaccines and rates of routine childhood vaccination have been declining around the world since the pandemic, when many countries saw the instatement of COVID-19 vaccine mandates. ObjectivesWe leveraged the COVID-19 add-on study, conducted by the CHILD Cohort Study (Canadas most phenotypically diverse, large prospective longitudinal birth cohort), to determine cha...

ObjectivePregnant women are at higher risk of severe COVID-19, and vaccination significantly reduces the risk of severe infection. Despite its benefits, only 13% of pregnant women in the U.S. had received the updated 2024-25 vaccine by December 2024, with uptake varying across sociodemographic groups. This study examines perceptions on COVID-19 vaccination during pregnancy among U.S. adults enrolled in the Chasing Covid Cohort, analyzing responses across 16 surveys between March 2020 and Decembe...

Vaccine hesitancy emerged as a major challenge during the COVID-19 pandemic and has persisted beyond it, raising concerns about public readiness for vaccination in future pandemics. While extensive research has examined vaccine hesitancy for COVID-19 and routine immunization, it is unknown how the general population would respond to vaccination in a future pandemic, and what conditions might facilitate acceptance. Here, we analyzed data from a nationwide internet-based survey conducted in Japan ...

In 2024, mpox cases surged in the Democratic Republic of the Congo (DRC) with cross-border spread to Burundi. We developed a transmission-dynamic model calibrated against surveillance data to understand drivers in enzootic (Clade Ia) and non-enzootic (Clade Ib) areas, and the potential impact of vaccination. In non-enzootic areas we estimated that 58-84% of transmission occurred within sexual networks. MVA-BN vaccination of sex workers could have averted 91% (95% CrI 81%-98%) of infections in Su...

BackgroundMalawi has one of the highest incidences and mortality due to cervical cancer, which is caused by the human papillomavirus (HPV). Achieving high HPV vaccination coverage is critical for advancing the World Health Organization (WHO) cervical cancer elimination strategy. This study aims to describe the spatio-temporal uptake of the first and second doses of the HPV vaccine in Malawi and to investigate the covariates associated with the uptake. MethodsWe analysed HPV vaccination coverage...

Cervical cancer is a significant global health issue, ranking as the fourth highest cause of cancer-related deaths among women globally. HPV vaccination for girls aged 9-14 offers a powerful tool for cervical cancer prevention, yet global coverage remains low, particularly in low- and middle-income countries. While research has documented parental and stakeholder perspectives, few studies center on girls own experiences and how gender norms shape their access and decision-making. This study appl...

IntroductionWomen living with HIV (WLHIV) face an increased risk of cervical cancer (CC). With inequitable HPV vaccine access and a programmatic focus on girls-only school-based delivery, many WLHIV in high HIV prevalence countries remain vulnerable to HPV infection and CC. We assessed the incremental impact of adding catch-up vaccination for WLHIV in South Africa. MethodsWe used two independently developed HPV/CC and HIV transmission models to predict the incremental impact of catch-up HPV vac...

The prospective design of vaccine efficacy trials for deployment in outbreaks requires advance consideration of plausible outbreak scenarios, anticipated vaccine characteristics, and logistical and ethical constraints. As part of CEPIs 100 Days Mission to accelerate vaccine development against a novel Disease X, we evaluated trial designs for a hypothetical Nipah-X outbreak. We assumed Nipah-X would share key features with Nipah, including high case fatality rates and substantial super-spreading...

BackgroundIndia bears the worlds highest cervical cancer burden, yet awareness and uptake of the effective HPV vaccine remain low. Although Kerala has initiated pilot HPV vaccination programmes, stakeholder knowledge, attitudes, and practices (KAP) are not well documented. This pilot study aimed to assess the feasibility of a KAP study and to identify gaps in the questionnaire, for future analytical modelling. MethodsA cross-sectional pilot study was conducted in a school in Pulinkunnu, Kerala,...

Background Persistent inequities in immunisation coverage, particularly among zero-dose and under-immunised children, continue to challenge Pakistan's Expanded Programme on Immunization. Weak feedback loop, inconsistent data quality, and limited real-time monitoring impede effective decision-making. This Implementation Research was conducted under the MAINSTREAM Initiative funded by Alliance for Health Policy and Systems Research (AHPSR) and supported by the Aga Khan Community Health Services De...

Residual blood specimens collected at health care facilities provide a low-cost and readily available specimen source to monitor population immunity through serological surveillance compared to more resource-intensive probability-based surveys. Despite concerns about the representativeness of these specimens, there has recently been increased interest in the use of residual specimens, driven by the need for rapid estimates of seroprevalence during outbreaks to inform response and prevention. Alt...

BackgroundAdverse Events Following Immunization (AEFI) remain a significant concern for immunization programs, as underreporting can undermine public confidence and compromise vaccine safety monitoring. Despite significant efforts to address challenges associated with AEFI reporting globally, the AEFI reporting rate in the Ahafo Region of Ghana still remains a challenge. This study investigated healthcare workers knowledge and practices regarding AEFI reporting in the Ahafo Region of Ghana, aimi...

BackgroundSeveral Shigella vaccine candidates are in late stages of development, and the design of large Phase 3 trials in target populations is underway. Immunologic catch up by unvaccinated infants to vaccinated infants, which is determined by the trial site-specific force of infection, may modify the vaccine efficacy (VE) estimates observed in such trials. To set expectations and support optimal planning of future Shigella vaccine trials, we aimed to quantify the potential bias of VE estimate...

BackgroundCOVID-19 vaccine hesitancy remains a public health issue despite the fact that vaccines are readily available and recommended for all persons aged [≥]5 years in the United States. We aimed to describe parents plan to vaccinate their children in two different populations: families in a prospective, longitudinal cohort study and families experiencing homelessness enrolled in cross-sectional surveillance for acute respiratory infections. MethodsParticipants were parents/guardians of c...

ObjectiveAlthough COVID-19 vaccination is important for People Living with HIV given their elevated infection and comorbidity risks, some PLHIV are hesitant to accept vaccination. Hence, we conducted a cross-sectional study in British Columbia, Canada, aimed to identify socio-economic and health-related factors predicting COVID-19 vaccine uptake and contributing to hesitancy among PLHIV. MethodsA 34-item anonymous self-administered survey was disseminated to PLHIV accessing services through HIV...