A forecasting approach to navigate uncertainty in Lassa fever vaccine demand and guide supply planning

Introduction: Lassa fever poses a growing public health threat across West Africa, with outbreaks shaped by complex ecological and socio-environmental dynamics. Delays in detection limit the effectiveness of reactive responses. In collaboration with national and international partners, we developed the Sentinel Forecasting System: An open-source platform integrating nowcasts and short-term monthly forecasts to support anticipatory public health action, including vaccine trial planning and outbreak preparedness. Methods: Sentinel combines ecological models of Mastomys natalensis habitat, remotely sensed environmental data (e.g. rainfall, vegetation), population and mobility layers, and surveillance data from Nigeria (2012–2023). A Bayesian hierarchical spatiotemporal model generates nowcasts and monthly forecasts. Outputs informed modelling of routine and reactive vaccination strategies across Nigeria and West Africa, including estimates of vaccine impact, demand, and stockpiling needs. Results: Sentinel accurately captured seasonal and interannual shifts in risk. Vaccine effectiveness modelling found that routine vaccination before the Lassa season (August–November) could avert up to 70% of severe cases, compared to ~25% with outbreak response starting in January. Targeting high-incidence or environmentally suitable areas offers substantial impact with feasible coverage. Ecological models identified broader spillover zones across West Africa; routine vaccination in these areas or stockpiling (e.g. 1M doses for pregnant people, 35,000 for healthcare workers) would improve protection in hard-to-reach regions. Conclusion: By integrating diverse data streams into real-time forecasts, Sentinel enables more proactive and targeted Lassa fever interventions. The approach supports smarter decision-making for vaccine trial planning, surveillance, and response. Next steps include regional scale-up and embedding Sentinel within national public health systems.

Lassa fever (LF) is caused by a viral pathogen with pandemic potential. LF vaccines have the potential to prevent significant disease in individuals at risk of infection, but no such vaccine has been licensed or authorised for use thus far. We conducted a scoping review to identify and compare registered phase 1, 2 or 3 clinical trials of LF vaccine candidates, and appraise the current trajectory of LF vaccine development. We systematically searched 24 trial registries, PubMed, relevant conference abstracts and additional grey literature sources up to 27 October 2022. After extracting key details about each vaccine candidate and each eligible trial, we qualitatively synthesised the evidence. We found that four LF vaccine candidates (INO-4500, MV-LASV, rVSV∆G-LASV-GPC, and EBS-LASV) have entered the clinical stage of assessment. Five phase 1 trials (all focused on healthy adults) and one phase 2 trial (involving a broader age group from 18 months to 70 years) evaluating one of these vaccines have been registered to date. Here, we describe the characteristics of each vaccine candidate and trial and compare them to WHO's target product profile for Lassa vaccines. Though LF vaccine development is still in early stages, current progress towards a safe and effective vaccine is encouraging.

BackgroundA face-to-face survey of 158 policymakers and other influential professionals was conducted in eight dengue-endemic countries in Asia (India, Sri Lanka, Thailand, Vietnam) and Latin America (Brazil, Colombia, Mexico, Nicaragua) to provide an indication of the potential demand for dengue vaccination in endemic countries, and to anticipate their research and other requirements in order to make decisions about the introduction of dengue vaccines. The study took place in anticipation of the licensure of the first dengue vaccine in the next several years.Methods/Principal FindingsSemi-structured interviews were conducted on an individual or small group basis with government health officials, research scientists, medical association officers, vaccine producers, local-level health authorities, and others considered to have a role in influencing decisions about dengue control and vaccines. Most informants across countries considered dengue a priority disease and expressed interest in the public sector use of dengue vaccines, with a major driver being the political pressure from the public and the medical community to control the disease. There was interest in a vaccine that protects children as young as possible and that can fit into existing childhood immunization schedules. Dengue vaccination in most countries surveyed will likely be targeted to high-risk areas and begin with routine immunization of infants and young children, followed by catch-up campaigns for older age groups, as funding permits. Key data requirements for decision-making were additional local dengue surveillance data, vaccine cost-effectiveness estimates, post-marketing safety surveillance data and, in some countries vaccine safety and immunogenicity data in the local population.Conclusions/SignificanceThe lookout for the public sector use of dengue vaccines in the eight countries appears quite favorable. Major determinants of whether and when countries will introduce dengue vaccines include whether WHO recommends the vaccines, their price, the availability of external financing for lower income countries, and whether they can be incorporated into countries' routine immunization schedules.

IntroductionThe Palestinian Ministry of Health (MOH) started a routine rotavirus immunization program with ROTARIX in May 2016, with support for vaccine procurement and introduction provided through a global development organization. In 2018, financial responsibility for rotavirus vaccine procurement was transferred to the Palestinian government, which elected to shift to ROTAVAC vaccine because of its lower price per dose. This study aims to assess the cost, impact, and cost-effectiveness of rotavirus vaccination, specifically evaluating the economic implications of the change in vaccine product, accounting for the different characteristics of each rotavirus vaccine used.MethodsWe conducted primary and secondary data collection to assess the introduction, procurement, supply chain, and service delivery costs related to each vaccine. We used the UNIVAC model to project costs and benefits of rotavirus vaccination over a 10-year period comparing the use of ROTARIX versus no vaccination; ROTAVAC versus no vaccination; and ROTAVAC versus ROTARIX. We undertook scenario and probabilistic analyses to capture uncertainty in some of the study parameters. We used a 3% discount rate, and all costs are in 2018 US$.ResultsThe cost to deliver one dose was lower for ROTAVAC than ROTARIX (US$2.36 versus $2.70), but the total cost per course, excluding vaccine cost, favored ROTARIX ($7.09 versus $5.39). Both vaccines had high probability of being cost-effective interventions in Palestine compared to no vaccine. Because of lower vaccination program costs for ROTAVAC, however, switching from ROTARIX to ROTAVAC was cost-saving.ConclusionNational decision-makers should consider systematically assessing multiple criteria beyond vaccine price when comparing the health and economic value of several products in order to fully account for all characteristics including product presentation, number of doses per course, cold chain volume, cost of delivery, and wastage.

The Economic Value of Childhood Varicella Vaccination in France and Germany

The Procurement of a COVID-19 Vaccine in Developing Countries: Lessons from the 2009-H1N1 Pandemic

Ebola vaccine trials back on track

Building global vaccine manufacturing capacity: Spotlight on Africa

Introduction: The routine vaccine injections are one of the most common and painful procedures during childhood specifically in infancy. In order to improve the effectivity of pain reduction during routine vaccination OPD this study was done to analyse the effectiveness of audio-visual gadgets as a distraction tool for pain reduction in infants during the vaccination procedure. Methods: A comparative observational study conducted at a tertiary healthcare center vaccination out patient department. Children aged 1 month to 2 years receiving the vaccine were included in the study. The study group was exposed to audio-visual clip while the control group received the vaccine as per routine vaccination protocol. The Face, Legs, Activity, Cry, Controllability Scale score was used to assess the behavioural reactions to pain which assesses five behavioural areas. The study protocol was approved by the Institute Ethics Committee (Reference number: BJGMC/IEC/1122238-238).Results: The Face, Legs, Activity, Cry, Controllability Scale score were studied among two groups, it was observed that the pain score and every component of the score had a statistically significant lower mean score in audio-visual group as compared to the control group. Mean pain score in the audio-visual group was 6.31±0.79 as compared to 9.57±0.65 in the control group with the p value of 0.001.Conclusions: A lower pain score in response to vaccination with an audio-visual distraction indicates that it can be regularly used to reduce pain during the vaccination procedure and can be used during different painful procedures.

Whole-cell diphtheria-tetanus-pertussis (DTP) and oral polio vaccine (OPV) were introduced to children in Guinea-Bissau in 1981. We previously reported that DTP in the target age group from 3 to 5 months of age was associated with higher overall mortality. DTP and OPV were also given to older children and in this study we tested the effect on mortality in children aged 6-35 months. In the 1980s, the suburb Bandim in the capital of Guinea-Bissau was followed with demographic surveillance and tri-monthly weighing sessions for children under 3 years of age. From June 1981, routine vaccinations were offered at the weighing sessions. We calculated mortality hazard ratio (HR) for DTP-vaccinated and DTP-unvaccinated children aged 6-35 months using Cox proportional hazard models. Including this study, the introduction of DTP vaccine and child mortality has been studied in three studies; we made a meta-estimate of these studies. At the first weighing session after the introduction of vaccines, 6-35-month-old children who received DTP vaccination had better weight-for-age z-scores (WAZ) than children who did not receive DTP; one unit increase in WAZ was associated with an odds ratio of 1.32 (95% CI = 1.13-1.55) for receiving DTP vaccination. Though lower mortality compared with not being DTP-vaccinated was, therefore, expected, DTP vaccination was associated with a non-significant trend in the opposite direction, the HR being 2.22 (0.82-6.04) adjusted for WAZ. In a sensitivity analysis, including all children weighed at least once before the vaccination program started, DTP (±OPV) as the most recent vaccination compared with live vaccines or no vaccine was associated with a HR of 1.89 (1.00-3.55). In the three studies of the introduction of DTP in rural and urban Guinea-Bissau, DTP-vaccinated children had an HR of 2.14 (1.42-3.23) compared to DTP-unvaccinated children; this effect was separately significant for girls [HR = 2.60 (1.57-4.32)], but not for boys [HR = 1.71 (0.99-2.93)] (test for interaction p = 0.27). Although having better nutritional status and being protected against three infections, 6-35 months old DTP-vaccinated children tended to have higher mortality than DTP-unvaccinated children. All studies of the introduction of DTP have found increased overall mortality.

Today, vaccines play a crucial role in ensuring personal safety and are the most effective method for preventing related diseases. The ages over which vaccines are efficacious, from infancy to the old, is of utmost importance. With the recent outbreak of COVID-19 in 2019, the demand for vaccines and their usage has significantly increased. This surge in demand has led to issues such as vaccine counterfeiting and related problems, which have raised concerns among the public regarding vaccine administration. As a result, this has also resulted in a lack of trust in vaccine manufacturing companies and raised doubts about production processes. To address these concerns, this study proposed a vaccine production supervision system with Internet of Things (IoT) device based on blockchain. By utilizing IoT devices, vaccine-sensitive production data can be collected and encrypted and leaks that could lead to great benefit losses for vaccine manufacturing companies can also be prevented. This system adopts a digital signature technique to import immutable characteristics to the data, offering conclusive evidence in case any issues occur with the vaccine in the future. Finally, the system also integrates with the Inter Planetary File System (IPFS) with a blockchain solution, storing manufacturing plant vaccine production records in a secure, publicly accessible, and decentralized storage space, and also enabling public verification.

Immune Response 2019 : Factors influencing intention to obtain the HPV vaccine among a population of universitywomen in morocco - Dr. Aicha yacouti â University of Hassan

Early indication for a reduced burden of radiologically confirmed pneumonia in children following the introduction of routine vaccination against Haemophilus influenzae type b in Nha Trang, Vietnam

With increased demand for smallpox vaccination during the nineteenth century, vaccination days--early mass vaccination campaigns--were conducted over time-limited periods to rapidly and efficiently protect maximum numbers of susceptible persons. Two centuries later, the challenge to rapidly and efficiently protect populations by mass vaccintion continues, despite the strengthening of routine immunization services in many countries through the Expanded Programme on Immunization strategies and GAVI support. Perhaps the most widely accepted reason for mass vaccination is to rapidly increase population (herd) immunity in the setting of an existing or potential outbreak, thereby limiting the morbidity and mortality that might result, especially when there has been no routine vaccination, or because populations have been displaced and routine immunization services disrupted. A second important use of mass vaccination is to accelerate disease control to rapidly increase coverage with a new vaccine at the time of its introduction into routine immunization programmes, and to attain the herd immunity levels required to meet international targets for eradication and mortality reduction. In the twenty-first century, mass vaccination and routine immunization remain a necessary alliance for attaining both national and international goals in the control of vaccine preventable disease.

Countries with fragile health systems like South Sudan experienced significant impacts on routine immunization during the COVID-19 pandemic. Routine immunization in children aged younger than 1 year declined due to pandemic-related constraints and was compounded by the introduction of the COVID-19 vaccine, which was met with hesitancy and reluctance. When South Sudan reported the first COVID-19 case in March 2020, the CORE Group Partners Project (CGPP) rapidly integrated the COVID-19 outbreak response into its ongoing polio eradication activities, leveraging the existing polio infrastructure and human resources. We describe the integration process, results, and challenges and detail the impact of the integration on coverage for both routine immunization and COVID-19 vaccinations. Efforts to integrate COVID-19 vaccination and routine immunization service delivery were implemented in 5 phases: assessing the need, developing multisector collaborations, developing a service delivery plan, assessing implementation readiness, and implementing and evaluating the service delivery plan. Integration efforts prioritized coordination, training vaccinators and volunteers, development of microplans, data management, and last-mile vaccine delivery. Integrated service delivery was implemented through "one-stop shop" sessions where communities accessed routine immunizations for children, COVID-19 vaccinations for adults, and other primary health services. Integrating health service delivery contributed to improved routine immunization coverage among children, improved COVID-19 vaccination coverage among adults, reduced cost for service delivery, and increased access to more comprehensive health services in hard-to-reach communities. COVID-19 vaccinations were delivered at US$4.70 per dose, a cost substantially lower than other reported delivery mechanisms. Integration can yield positive results and improve access to vaccination and other health services for communities. However, it requires clear policy guidelines, commitment, and strong collaboration. Challenges included resistance from stakeholders, overstretched human resources, and diversion of funding and attention from program areas, which were overcome through deliberate high-level advocacy, partnership, and intensified community engagement.