Mark Jit
Mark Jit
Scroll
Chair and Professor of the Department of Global and Environmental Health
-
Professional overview
-
Mark Jit is the inaugural chair and a professor in the Department of Global and Environmental Health. He was formerly head of the Department of Infectious Disease Epidemiology & Dynamics and co-director of the Global Health Economics Centre (GHECO) at the London School of Hygiene & Tropical Medicine (LSHTM). He holds honorary appointments at LSHTM as well as the University of Hong Kong (HKU) and the National University of Singapore (NUS).
Dr. Jit’s research focuses on epidemiological and economic modeling of vaccines to support evidence-based public health decision making. He has published papers covering a range of vaccine-preventable or potentially vaccine-preventable diseases including COVID-19, measles, HPV, pneumococcus, rotavirus, influenza, Group B Streptococcus, dengue, EV71 and RSV as well as methodological papers advancing the ways vaccines are evaluated. This work has influenced many of the major changes to immunization policy in countries around the world. Dr. Jit has served on a number of expert advisory committees in the UK as well as for international organizations such as the World Health Organization. He also organises or contributes to academic and professional courses on vaccine modeling, economics and decision science around the world.
Dr. Jit received his BSc and PhD in Mathematics from University College London, specializing in mathematical biology, and a Master of Public Health degree from King’s College London.
Visit Dr. Jit's Google Scholar's page to learn more about his research portfolio.
-
Education
-
BSc, Mathematics, University College LondonPhD, Mathematics, University College LondonMPH, Public Health, King's College London
-
Honors and awards
-
Clarivate Highly Cited Researcher (20222023)Fellow of the Academy of Medical Sciences (2023)Training Fund Award, Health Protection Agency (2007)Andrew Rosen Prize, University College London (1999)Institute of Mathematics and its Applications Award (1998)Departmental Research Studentship, University College London (1998)Student Union Commendation, University College London (1997)Fillon Prize, University College London (1996)Pathfinder Award, University College London (1995)
-
Publications
Publications
Association between ambient temperature and childhood vaccination coverage in low- and middle-income countries
AbstractZheng, H., Zhu, Y., Chu, H., Xu, Z., Jit, M., Ding, Z., Zhou, X., Bachwenkizi, J., Chen, R., & Hou, Z. (n.d.).Publication year
2026Journal title
BMC medicineAbstractClimate change aggravates infectious diseases and their transmission, with the large impact on children in low- and middle-income countries (LMICs). Vaccination is an essential tool to prevent infectious disease outbreaks; however, the influence of climatic factors on pediatric vaccination rates globally is unclear.Economic evaluation of combination vaccines: Enabling a more comprehensive assessment of their benefits and challenges
AbstractDebellut, F., Constenla, D., Mvundura, M., Hausdorff, W. P., Hasso-Agopsowicz, M., Jit, M., Portnoy, A., Aggarwal, R., Sheel, M., Davies, N. G., Sim, S. Y. Y., Lambach, P., Postma, M., Gill, C., Giersing, B., & Pecenka, C. (n.d.).Publication year
2026Journal title
VaccineVolume
80Page(s)
128561AbstractEven though two widely used combination vaccines (measles-rubella- and diphtheria- tetanus-pertussis-containing vaccines) are universally acknowledged as the cornerstones of pediatric immunization programs, the development of new combination vaccines for children has not been a priority for manufacturers, policy bodies, or decision-makers. At the same time, economic evaluations have not assessed the full array of benefits and risks associated with combination vaccines. As part of an effort to identify and prioritize potential new combination vaccines, we aimed to enhance efforts to establish their value, a crucial step toward a more thorough, quantifiable, and realistic assessment of these vaccines. We reviewed the literature on economic evaluations of combination vaccines to more precisely identify and define current gaps in value assessment. We identified a set of (often unvalued) benefits and risks and created a list of value drivers and metrics for potential inclusion in future evaluations. Value drivers were then categorized based on how they resonate with decision-makers' priorities and their contribution to product value. Metrics were categorized based on their quantifiability and their fit within existing economic evaluation frameworks. We developed a prioritized checklist of value drivers and metrics to assess combination vaccines through a consultative process involving numerous immunization stakeholders (e.g., immunization specialists, regional immunization advisors, policy bodies). The checklist was further refined through a convening of health economics experts and ultimately endorsed by the World Health Organization's Immunization and Vaccines-related Implementation Research Advisory Committee. This checklist of prioritized value drivers and metrics is meant to serve as a tool for analysts to value combination vaccines and help ensure these vaccines are more comprehensively assessed by decision-makers to inform investment decisions or adoption.Estimating the Uptake of and Factors Associated With a New Vaccine Outside of the National Immunisation Programme: A Case Study of the EV-A71 Vaccine Against Hand, Foot, and Mouth Disease
AbstractLiu, F., Cui, F., Quilty, B. J., Song, Y., Tong, X., Flasche, S., Jit, M., Li, Z., Chang, Z., & Liu, Y. (n.d.).Publication year
2026Journal title
Journal of medical virologyVolume
98Issue
1Page(s)
e70776AbstractThe burden of hand, foot, and mouth disease (HFMD) in children under five is substantial, with the greatest burden in China. Most cases are mild, although some are severe and even fatal. A vaccine against EV-A71, the pathogen most commonly associated with severe HFMD, was licensed in China in Dec 2015 but not introduced into the National Immunisation Programme (NIP). It was hence not covered by routine national vaccine surveillance and its coverage remained unknown for the years following its initial licensure. Here we report the results of a novel data collection and analysis approach to address this knowledge gap. Local public health entities were invited to report county-specific numbers of EV-A71 vaccine doses administered between 2016 and 2019 in mainland China. A cohort model was then used to estimate vaccine coverage. The association between county-level factors (epidemiological, socioeconomic, demographic, and environmental) and vaccine coverage was assessed using zero-inflated beta regression models. We received responses from 2,248 out of 3,252 counties in 23 of 31provinces in mainland China. The median county-level EV-A71 vaccine coverage was 10.17% [IQR: 3.50%, 19.39%] in 2018 and 16.70% [IQR: 8.78%, 27.45%] in 2019. However, the median absolute differences in coverage (i.e., max-min) within-prefecture were ~30%. Results from the regression model indicate that low vaccine coverage was associated with low socioeconomic status, small populations and high proportions of young children. Coverage of EV-A71 vaccines was low in China prior to the COVID-19 pandemic, with substantial geographical disparities over 4 years after the initial vaccine licensure. Our results illustrate the private market response to a new childhood vaccine that is licensed but not centrally funded. Despite economic growth, vaccine coverage among marginalised populations will likely be low without targeted policy and financial support.Evaluating the broader impact of improved influenza vaccines: A full value of vaccine assessment approach
AbstractSoble, A., Koh, M., Taaffe, J., Procter, S. R., Eggo, R. M., Malvolti, S., Jit, M., Goldin, S., Bar-Zeev, N., Bresee, J., & Lambach, P. (n.d.).Publication year
2026Journal title
VaccineVolume
60 Suppl 2Page(s)
128166AbstractSeasonal influenza remains a significant global public health challenge, causing substantial morbidity and mortality each year and there remains a need for more effective and durable influenza vaccines. To direct and accelerate research efforts, a full value of vaccine assessment (FVVA) was initiated to quantify the value of next-generation, improved influenza vaccines and identify key challenges that may limit their uptake once available. The FVVA utilized a mixed-methods approach with rapid assessment of literature, stakeholder interviews, and surveys, and quantitative data analysis to estimate the full value of influenza vaccines with improved characteristics. These analyses found that if improved influenza vaccines are broadly employed, depending on their characteristics, using our demand forecast they could avert 6.6-18 billion additional influenza cases, 2.3-6.2 million additional influenza deaths, and 21-57 million disability-adjusted life years (DALYs) between 2025 and 2050 beyond those averted by current seasonal influenza vaccines. Under this scenario, introducing improved influenza vaccines could be cost-effective in 9-48 % of countries at the lowest assumed price point. However, uncertainties about price and future vaccine coverage may impact the potential cost-effectiveness. Furthermore, from the producer perspective, the FVVA highlighted the robust financial value proposition to develop and commercialize improved influenza vaccines, in both established and emerging markets. Strongly tiered prices could make these vaccines cost-effective in more countries and boost impact further. To ensure that improved influenza vaccines achieve the greatest public health benefit, effective collaboration between vaccine developers, vaccine manufacturers, donors, financiers, multilateral organisations, and policy- and decision-makers will be essential.The benefits and risks of maternal RSV vaccination on mortality in South Africa: A modeling study
Failed generating bibliography.AbstractPublication year
2026Journal title
PLoS medicineVolume
23Issue
1Page(s)
e1004625AbstractMaternal respiratory syncytial virus (RSV) vaccine, RSV prefusion F protein vaccine (RSVpreF (Abrysvo)), was found to be safe and efficacious in the MATISSE trial. However, post-hoc stratified analyses identified an excess of preterm births in the intervention arm in two upper-middle-income countries, most prominently in South Africa. This study weighs the potential benefits and risks in mortality associated with maternal RSV vaccination in South Africa, assuming the increased risk of preterm births observed in the trial was caused by vaccination.The epidemiological effect and cost-effectiveness of expanded age eligibility for recombinant zoster vaccination in England
AbstractKu, C.-C. C., Rosello, A., Walker, J., Pouwels, K. B., Baguelin, M., Davies, N. G., & Jit, M. (n.d.).Publication year
2026Journal title
VaccineVolume
78Page(s)
128405AbstractSince September 2023, England's national immunisation programme has offered the recombinant zoster vaccine (RZV) to adults aged 65-79 as a preventative measure against shingles (herpes zoster) and its complications. However, adults aged 80 and over are currently not eligible for the vaccine. We aimed to evaluate the feasibility and cost-effectiveness of providing RZV to adults aged 80 and older in England.The potential impact of reduced international donor funding on the household economic burden of tuberculosis in low- and middle-income countries: A modeling study
AbstractPortnoy, A., Clark, R. A., Jit, M., McQuaid, C. F. F., Richards, A. S., Bakker, R., Sumner, T., Prŷs-Jones, T. O., Houben, R. M. G. J., White, R. G., Horton, K. C., & Menzies, N. A. (n.d.).Publication year
2026Journal title
PLoS medicineVolume
23Issue
2Page(s)
e1004946AbstractRecent shifts in the global health funding landscape-most notably the dismantling of the United States Agency for International Development (USAID) and possible reduced contributions to the Global Fund to Fight AIDS, TB, and Malaria (Global Fund)-threaten essential tuberculosis (TB) services in low- and middle-income countries (LMICs). We quantified the potential impact on the household economic burden of TB.A systematised review and evidence synthesis on the broader societal impact of vaccines against Salmonella
AbstractDemirtas, E. D., Barnard, R., Lee, J., & Jit, M. (n.d.).Publication year
2025Journal title
npj VaccinesVolume
10Issue
1AbstractVaccines against Salmonella Typhi are available, while vaccines against invasive non-typhoidal Salmonella are in development. Investments in vaccine development and introduction need to be informed by a full value of vaccines assessment, including consideration of broader societal impacts of salmonellae disease. We reviewed literature on these broader impacts in low- and middle-income countries to inform a conceptual framework. We found 16 studies relevant to Salmonella, but only one study on non-typhoidal Salmonella. Despite variations in study design, methodology, and study quality, salmonellae infections were largely associated with negative broader societal impacts, including detriments in childhood physical development (very weak association), childhood educational development (strong to very strong association), household security (moderate association), public health spending (moderate association), and national income (moderate to strong association). Study quality was low for all impacts except childhood physical development. There were no studies measuring economic impact of antimicrobial resistance, changes in household behaviour or health inequalities.A systematised review and evidence synthesis on the broader societal impact of vaccines against Salmonella
AbstractDemirtas, E. D. D., Barnard, R., Lee, J., & Jit, M. (n.d.).Publication year
2025Journal title
NPJ vaccinesVolume
10Issue
1Page(s)
21AbstractVaccines against Salmonella Typhi are available, while vaccines against invasive non-typhoidal Salmonella are in development. Investments in vaccine development and introduction need to be informed by a full value of vaccines assessment, including consideration of broader societal impacts of salmonellae disease. We reviewed literature on these broader impacts in low- and middle-income countries to inform a conceptual framework. We found 16 studies relevant to Salmonella, but only one study on non-typhoidal Salmonella. Despite variations in study design, methodology, and study quality, salmonellae infections were largely associated with negative broader societal impacts, including detriments in childhood physical development (very weak association), childhood educational development (strong to very strong association), household security (moderate association), public health spending (moderate association), and national income (moderate to strong association). Study quality was low for all impacts except childhood physical development. There were no studies measuring economic impact of antimicrobial resistance, changes in household behaviour or health inequalities.A systematised review of seasonal influenza case-fatality risk
AbstractFilipe, J. A. N., Wong, C. K. H., van Leeuwen, E., Goodfellow, L., Procter, S. R., & Jit, M. (n.d.).Publication year
2025Journal title
VaccineVolume
60 Suppl 2Page(s)
128011AbstractCase-fatality risk (CFR) is an important indicator of disease severity for influenza infection and an input to estimates of influenza burden and vaccination impact. However, CRF estimates based on laboratory-confirmed cases (cCFR) are more-highly sensitive to features of the local health-care system and surveillance. Estimates based on diagnosed-symptomatic cases (sCFR) are likely to be more consistent across health systems but are less commonly reported. We present a systematised review of sCFR for seasonal influenza to determine the availability of studies, variation across their sCFR estimates, and factors driving this variation. We identified 10 studies reporting sCFR, or primary data for its direct estimation, resulting in 40 location and season-specific point estimates (range 0.3-908 per 100,000 cases). There is considerable variation in sCFR across geographies, which was not linearly related to key socio-economic factors, but the variation can be even larger across seasons in a geography. The wide variation across studies and the lack of studies in many world regions point to the need for standardised protocols and more data collection.A vaccine chatbot intervention for parents to improve HPV vaccination uptake among middle school girls : a cluster randomized trial
AbstractHou, Z., Wu, Z., Qu, Z., Gong, L., Peng, H., Jit, M., Larson, H. J., Wu, J. T., & Lin, L. (n.d.).Publication year
2025Journal title
Nature MedicineAbstractConversational artificial intelligence, in the form of chatbots powered by large language models, offers a new approach to facilitating human-like interactions, yet its efficacy in enhancing vaccination uptake remains under-investigated. This study assesses the effectiveness of a vaccine chatbot in improving human papillomavirus (HPV) vaccination among female middle school students aged 12–15 years across diverse socioeconomic settings in China, where HPV vaccination is primarily paid out-of-pocket. A school-based cluster randomized trial was conducted from 18 January to 31 May 2024. The study included 2,671 parents from 180 middle school classes stratified by socioeconomic setting, school and grade level in Shanghai megacity, and urban and rural regions of Anhui Province. Participants were randomly assigned to either the intervention group (90 classes, 1,294 parents), which engaged with the chatbot for two weeks, or the control group (90 classes, 1,377 parents), which received usual care. The primary outcome was the receipt or scheduled appointment of the HPV vaccine for participants’ daughters. In intention-to-treat analyses, 7.1% of the intervention group met this outcome versus 1.8% of the control group (P < 0.001) over a two-week intervention period. In addition, there was a statistically significant increase in HPV vaccination-specific consultations with health professionals (49.1% versus 17.6%, P < 0.001), along with enhanced vaccine literacy (P < 0.001) and rumor discernment (P < 0.001) among participants using the chatbot. These findings indicate that the chatbot effectively increased vaccination and improved parental vaccine literacy, although further research is necessary to scale and sustain these gains. Clinical trial registration: NCT06227689.An Introduction to Costing and the Types of Costs Used within Health Economic Studies
AbstractTurner, H. C., Rivillas-Garcia, J. C. C., Prinja, S., Hung, T. M. M., Dabak, S. V. V., Asare, B. A., Jit, M., & Teerawattananon, Y. (n.d.).Publication year
2025Journal title
PharmacoEconomics - openVolume
9Issue
6Page(s)
849-868AbstractThe number of published health economic analyses, especially economic evaluations, has rapidly expanded globally since the 1990s, and costs are an essential component of such studies. Cost is a general term that refers to the value of the resources/inputs used to produce a good or service. However, within health economics, there are several different types of costs (such as financial, economic, unit, average, etc.). The terminology and application of these cost types often differ, leading to inconsistencies in the health economics literature. These inconsistencies create challenges in comparing studies and hinder the use of health economic analyses to effectively inform policy decisions. This paper aims to provide an up-to-date overview of the cost types, key cost terms, and definitions of different cost measures used within health economics, while highlighting key inconsistencies in the literature. We also discuss common adjustments made to cost data, such as accounting for inflation, discounting, and currency conversions, as well as the influence of economies of scale and scope on cost estimates. We highlight that the different definitions/categories for the different types of costs are not mutually exclusive and that the type of cost that should be used will depend on the purpose of the study, highlighting recommendations of what to do in practice where relevant. The content was tailored to be relevant across both high-income and LMIC contexts.Cost-effectiveness analysis of switching from a bivalent to a nonavalent HPV vaccination programme in China : a modelling study
AbstractGao, M., Hu, S., Zhao, X., You, T., Hong, Y., Liu, Y., Qiao, Y., Jit, M., Zhao, F., & Wang, C. (n.d.).Publication year
2025Journal title
The Lancet Regional Health - Western PacificVolume
56AbstractBackground: Several domestically-manufactured nonavalent HPV vaccine candidates are in phase III clinical trials and their future availability may address the current dilemma of insufficient supply and high price of the overseas-manufactured nonavalent HPV vaccine in China. We compare the population-level effectiveness and cost-effectiveness of switching to nonavalent HPV vaccination in China. Methods: We used a previously validated transmission model to project the lifetime costs and effectiveness of five same-vaccine and two mixed-vaccine strategies. Nonavalent HPV vaccines were assumed to be available and meet the production requirements for national vaccination between 2030 and 2050. All women living or projected to be born in China during 2023–2100 were considered. We adopted a societal perspective and determined optimal strategies using cost-effectiveness efficiency frontiers. Findings: Under our pricing assumptions, switching to nonavalent vaccination was always cost-saving compared with maintaining the current bivalent vaccination programme, irrespective of the screening scenarios and the year when nonavalent vaccine was assumed to become available (status quo screening: net cost saving $2589–5211 million; improved screening: net cost saving $1852–3789 million). In the same-vaccine strategies, the optimal strategy changed from “routine nonavalent HPV vaccination with catch-up to age 18” to “switching from bivalent to nonavalent HPV vaccination” if nonavalent vaccination is available after 2035. Compared with the optimal same-vaccine strategy, adopting mixed schedules with bivalent and nonavalent vaccines would further save $1336–4280 million net costs and gain 87,000–833,000 QALYs, depending on the screening scenario and the year when nonavalent vaccine becomes available. Interpretation: Switching from bivalent to nonavalent HPV vaccination is likely to be cost-saving and have a significant impact on reducing the cervical cancer burden in China. Funding: Bill & Melinda Gates Foundation (INV-031449 and INV-003174) and CAMS Innovation Fund for Medical Sciences (CIFMS) (2021-I2M-1-004).Effect of a pay-it-forward strategy on reducing HPV vaccine delay and increasing uptake among 15- to 18-year-old girls in China: A randomized controlled trial
AbstractLi, J., Li, Y., Qin, C., He, Y., Lu, H., Xie, Y., Ong, J. J., Lu, Y., Yang, Y., Yang, F., Du, H., Gong, W., Zou, F., Larson, H. J., Jit, M., Lin, L., Smith, J. S., Geng, E. H., Xu, D., … Wu, D. (n.d.).Publication year
2025Journal title
PLoS medicineVolume
22Issue
7Page(s)
e1004535AbstractCatch-up human papillomavirus (HPV) vaccination is challenging in many low- and middle-income countries (LMICs). Pay-it-forward offers an individual a subsidized vaccine, then an opportunity to donate to help others access vaccinations. Our randomized control trial assessed the effectiveness of pay-it-forward in improving HPV vaccination among girls aged 15-18 years in China.Effect of a pay‑it‑forward strategy on reducing HPV vaccine delay and increasing uptake among 15‑ to 18‑year‑old girls in China : A randomized controlled trial
AbstractLi, J., Li, Y., Qin, C., He, Y., Lu, H., Xie, Y., Ong, J. J., Lu, Y., Yang, Y., Yang, F., Du, H., Gong, W., Zou, F., Larson, H. J., Jit, M., Lin, L., Smith, J. S., Geng, E. H., Xu, D., … Wu, D. (n.d.).Publication year
2025Journal title
PLoS MedicineVolume
22Issue
7 JulyAbstractBackground Catch-up human papillomavirus (HPV) vaccination is challenging in many low- and middle-income countries (LMICs). Pay-it-forward offers an individual a subsidized vaccine, then an opportunity to donate to help others access vaccinations. Our randomized control trial assessed the effectiveness of pay-it-forward in improving HPV vaccination among girls aged 15–18 years in China. Methods and findings This study was conducted from July 6, 2022, to June 9, 2023, in four community health centers (CHCs) in Chengdu, western China. Eligible participants were unvaccinated girls living in the service areas of CHCs. Participants were initially recruited via telephone and, after providing verbal consent, attended in-person visit where they were randomly assigned using the sealed envelope method to either the pay-it-forward arm (received a community subsidy of 47.7 USD covering the first vaccine and an opportunity to support others) or control arm (self-paid vaccination at the market price). Participants were unblinded only after the envelope was opened, while the CHC staff coordinators, physicians prescribing the vaccine, outcome assessors, and data analysts were blinded to the intervention allocation. The primary outcome was the first-dose HPV vaccination rate, verified against clinical records. Data were analyzed using the intention-to-treat approach. We identified 662 participants per phone invitation. A total of 321 participants showed up in the health centers and randomly assigned to the pay-it-forward arm (n=161) or control arm (n=160). Most caregivers were female (80.1%, 257/321). In the pay-it-forward arm, 55 of 161 (34.2%) girls received the HPV vaccine, compared with 28 of 160 (17.5%) girls in the control arm (adjusted proportion difference=17.9%, (95% CI [8.7%, 27.0%]; PEnhancing global health security responses through greater inclusion of the global south in infectious disease modelling
AbstractLeung, K., Cook, A. R., Wu, J. T., McVernon, J., Prem, K., Jit, M., Kingkaew, P., Mukhopadhyay, S., Isaranuwatchai, W., Pan-Ngum, W., Teerawattananon, Y., Huang, A., Djaafara, B., Sukmanee, J., Phuc, T. O. O., Laemlak, S., Chua, V. W., Rattanavipapong, W., & Dabak, S. V. V. (n.d.).Publication year
2025Journal title
BMJ global healthVolume
10Issue
8Abstract~Estimating the economic burden of invasive non-typhoidal infections in low- and middle-income countries
AbstractLee, J.-S. S., Hwang, Y., MacLennan, C. A. A., Jit, M., Excler, J.-L. L., & Kim, J. H. (n.d.).Publication year
2025Journal title
BMJ global healthVolume
10Issue
11AbstractInvasive non-typhoidal (iNTS) disease is a global health concern, particularly for sub-Saharan Africa. Despite high case fatality risks, there is no vaccine available against the disease. An obstacle to vaccine development is a lack of data on the economic burden of iNTS disease in many parts of the world. The main aim of the current study is to estimate the economic burden of iNTS disease in 123 countries.Financial risk protection from vaccines in 52 Gavi-eligible low- and middle-income countries: A modeling study
AbstractJiao, B., Sato, R., Mak, J., Patenaude, B., de Villiers, M., Deshpande, A., Gamkrelidze, I., Gaythorpe, K. A. M., Hallett, T. B., Jit, M., Li, X., Lopman, B., Nayagam, S., Razavi-Shearer, D., Tam, Y., Woodruff, K. H., Hogan, D., Mengistu, T., & Verguet, S. (n.d.).Publication year
2025Journal title
PLoS medicineVolume
22Issue
11Page(s)
e1004764AbstractPoverty alleviation is a major global development goal. Vaccines have the potential to provide financial risk protection (FRP) by preventing illnesses and associated healthcare costs. We estimate the lifetime FRP benefits generated by major vaccines among individuals vaccinated between 2000 and 2030 in low- and middle-income countries (LMICs).Fitting dynamic measles models to subnational case notification data from Ethiopia : Methodological challenges and key considerations
AbstractSbarra, A. N., Haeuser, E., Kidane, S., Abate, A., Abebe, A. M., Ahmed, M., Alemayehu, T., Amsalu, E., Aravkin, A. Y., Asgedom, A. A., Bayleyegn, N., Dagnew, M., Demisse, B., Etafa, W., Fetensa, G., Gebremeskel, T. G., Geremew, H., Gizaw, A. T., Hunde, G. A., … Mosser, J. F. (n.d.).Publication year
2025Journal title
PLoS computational biologyVolume
21Issue
4 AprilAbstractIn many settings, ongoing measles transmission is maintained due to pockets of un- or under-vaccinated individuals even if the critical vaccination threshold is reached nationwide. Therefore, assessing the underlying gaps in measles susceptibility within a population is essential for vaccination programs and measles control efforts. Recently, there have been increased efforts to use geospatial and small area methods to estimate subnational measles vaccination coverage in high-burden settings, such as in Ethiopia. However, the distribution of remaining susceptible individuals, either unvaccinated or having never previously been infected, across age groups and subnational geographies is unknown. In this study, we developed a dynamic transmission model that incorporates geospatial estimates of routine measles vaccination coverage, available data on supplemental immunization activities, and reported cases to estimate measles incidence and susceptibility across time, age, and space. We use gridded population estimates and subnational estimates of routine and supplemental measles vaccination coverage. To account for mixing between age-groups, we used a synthetic contact matrix, and travel times via a friction surface were used in a modified gravity model to account for spatial movement. We explored model fitting using Ethiopia as a case study. To address data-related and statistical challenges, we investigated a range of model parameterization and possible fitting algorithms. The approach with the best performance was a model fitted to case notifications adjusted for case ascertainment by using maximum likelihood estimation with block coordinate descent. This strategy was chosen because many data observations (and likely presence of unquantified uncertainty) yielded a steep likelihood surface, which was challenging to fit using Bayesian approaches. We ran sensitivity analyses to explore variations in vaccine effectiveness and compared patterns of susceptibility across space, time, and age. Substantial heterogeneity in reported measles cases as well as susceptibility persists across ages and second-administrative units. These methods and estimates could contribute towards tailored subnational and local planning to reduce preventable measles burden. However, computational and data challenges would need to be addressed for these methods to be applied on a large scale.Fitting dynamic measles models to subnational case notification data from Ethiopia: Methodological challenges and key considerations
AbstractSbarra, A. N., Haeuser, E., Kidane, S., Abate, A., Abebe, A. M., Ahmed, M., Alemayehu, T., Amsalu, E., Aravkin, A. Y., Asgedom, A. A., Bayleyegn, N., Dagnew, M., Demisse, B., Etafa, W., Fetensa, G., Gebremeskel, T. G., Geremew, H., Gizaw, A. T., Hunde, G. A., … Mosser, J. F. (n.d.).Publication year
2025Journal title
PLoS computational biologyVolume
21Issue
4Page(s)
e1012922AbstractIn many settings, ongoing measles transmission is maintained due to pockets of un- or under-vaccinated individuals even if the critical vaccination threshold is reached nationwide. Therefore, assessing the underlying gaps in measles susceptibility within a population is essential for vaccination programs and measles control efforts. Recently, there have been increased efforts to use geospatial and small area methods to estimate subnational measles vaccination coverage in high-burden settings, such as in Ethiopia. However, the distribution of remaining susceptible individuals, either unvaccinated or having never previously been infected, across age groups and subnational geographies is unknown. In this study, we developed a dynamic transmission model that incorporates geospatial estimates of routine measles vaccination coverage, available data on supplemental immunization activities, and reported cases to estimate measles incidence and susceptibility across time, age, and space. We use gridded population estimates and subnational estimates of routine and supplemental measles vaccination coverage. To account for mixing between age-groups, we used a synthetic contact matrix, and travel times via a friction surface were used in a modified gravity model to account for spatial movement. We explored model fitting using Ethiopia as a case study. To address data-related and statistical challenges, we investigated a range of model parameterization and possible fitting algorithms. The approach with the best performance was a model fitted to case notifications adjusted for case ascertainment by using maximum likelihood estimation with block coordinate descent. This strategy was chosen because many data observations (and likely presence of unquantified uncertainty) yielded a steep likelihood surface, which was challenging to fit using Bayesian approaches. We ran sensitivity analyses to explore variations in vaccine effectiveness and compared patterns of susceptibility across space, time, and age. Substantial heterogeneity in reported measles cases as well as susceptibility persists across ages and second-administrative units. These methods and estimates could contribute towards tailored subnational and local planning to reduce preventable measles burden. However, computational and data challenges would need to be addressed for these methods to be applied on a large scale.Global socioeconomic inequalities in vaccination coverage, supply, and confidence
AbstractWang, Q., Leung, K., Jit, M., Wu, J. T., & Lin, L. (n.d.).Publication year
2025Journal title
npj VaccinesVolume
10Issue
1AbstractSustainable Development Goal (SDG) adopted in 2015 aim to reduce inequalities and achieve universal health coverage, including access to essential vaccines for all. Using data from WHO, the Vaccine Confidence Project™, World Bank, and UNDP, we analyzed between-country inequalities in coverage of four vaccines (DTP1, DTP3, MCV1, and POL3), vaccine stock-outs, and vaccine confidence. Economic- and education-related inequalities in coverage (measured by the concentration index) declined from 2015 to 2019, increased in 2020, peaked in 2021, and have declined again since 2022. Inequalities increased continuously in the Region of the Americas. Over 2015–2022, 94 countries/territories reported at least one national level DTP-containing vaccine stock-out. Countries/territories with higher income or education attainment showed lower vaccine confidence. Our study underscores the decrease of inequalities in vaccination coverage following the SDG adoption in most regions, and emphasizes the need to address vaccine stock-outs and strength the vaccine confidence.Health impact and economic evaluation of the Expanded Program on Immunization in China from 1974 to 2024 : a modelling study
AbstractWang, C., Lai, X., Abbas, K., Pouwels, K. B., Zhang, H., Jit, M., & Fang, H. (n.d.).Publication year
2025Journal title
The Lancet Public HealthAbstractBackground: The Expanded Program on Immunization (EPI), initiated by WHO in 1974, is a cornerstone of public health. China's EPI covers more than a sixth of the world's population and includes eight routine vaccines with high coverage rates. This study aimed to estimate health and economic impacts of China's EPI over the past 50 years (1974–2024). Methods: This study mathematically modelled the impact of all eight routine vaccines in China's EPI against eight pathogens (measles, pertussis, hepatitis B, tuberculosis, hepatitis A, Japanese encephalitis, meningitis A, and poliomyelitis) based on data availability and their substantial disease burden, particularly accounting for non-linearities in vaccine impact. Health and economic outcomes were determined using mathematical models between a counterfactual scenario without vaccination (vaccine coverage set to zero) and the current vaccination scenario (routine vaccination scheduled at age 0–6 years), based on calendar year and birth cohort approaches. The health impact of China's EPI from 1974 to 2024 was measured in the number of cases, deaths, and disability-adjusted life-years (DALYs) averted. Findings: We estimated that China's EPI averted 703·02 million cases (95% credible interval 699·51–722·80) and 2·48 million deaths (2·14–2·97) in 1974–2024 based on the calendar year approach, equivalent to averting an estimated 160·22 million DALYs (145·05–196·99). Using the birth cohort approach, we predicted 707·41 million cases (703·93–727·03) and 7·01 million deaths (6·95–7·87) averted over the lifetime, corresponding to 279·02 million DALYs (265·78–316·12). From a societal perspective, the aggregated cost of vaccination was estimated to be US$124·06 billion (120·49–127·49), although the benefits amounted to $2417·85 billion (2359·38–2710·35). China's EPI yielded an aggregate benefit–cost ratio of 19·48 (18·82–22·08) from the societal perspective and 8·02 (7·64–8·80) from the provider's perspective. Interpretation: China's EPI has shown remarkable health and economic achievements, contributing to worldwide EPI success in the past 50 years. Further investment in EPI is warranted to sustain coverage and expand vaccine inclusion in China and globally. Funding: Beijing Natural Science Foundation. Translation: For the Chinese translation of the abstract see Supplementary Materials section.Health impact and economic evaluation of the Expanded Program on Immunization in China from 1974 to 2024: a modelling study
AbstractWang, C., Lai, X., Abbas, K., Pouwels, K. B., Zhang, H., Jit, M., & Fang, H. (n.d.).Publication year
2025Journal title
The Lancet. Public healthVolume
10Issue
12Page(s)
e1045-e1054AbstractThe Expanded Program on Immunization (EPI), initiated by WHO in 1974, is a cornerstone of public health. China's EPI covers more than a sixth of the world's population and includes eight routine vaccines with high coverage rates. This study aimed to estimate health and economic impacts of China's EPI over the past 50 years (1974-2024).Identification and sizing of the current use cases for seasonal influenza vaccines
AbstractSoble, A., Malhame, M., Malvolti, S., Mantel, C., Jit, M., Koh, M., Lambach, P., & Bresee, J. (n.d.).Publication year
2025Journal title
VaccineVolume
60 Suppl 2Page(s)
127233AbstractInfluenza disease continues to have significant global burden. Despite broader use of seasonal influenza vaccines in high resource settings, our understanding of use cases for seasonal influenza vaccines, their relative size, and their relationship to the barriers to adoption in different populations and settings, is limited. This study is a first attempt to identify the use cases for seasonal influenza vaccines to support the design of global influenza vaccination strategies that are better tailored to different implementation contexts and the development of improved influenza vaccines that are more aligned with the different user needs.Identification and sizing of the current use cases for seasonal influenza vaccines
AbstractSoble, A., Malhame, M., Malvolti, S., Mantel, C., Jit, M., Koh, M., Lambach, P., & Bresee, J. (n.d.).Publication year
2025Journal title
VaccineAbstractIntroduction: Influenza disease continues to have significant global burden. Despite broader use of seasonal influenza vaccines in high resource settings, our understanding of use cases for seasonal influenza vaccines, their relative size, and their relationship to the barriers to adoption in different populations and settings, is limited. This study is a first attempt to identify the use cases for seasonal influenza vaccines to support the design of global influenza vaccination strategies that are better tailored to different implementation contexts and the development of improved influenza vaccines that are more aligned with the different user needs. Methods: By applying a design-based user-centric approach, we implemented a process, including a desk review, a survey, and interviews, to define the current use cases for seasonal influenza vaccines. Results: Nine use cases have been identified as relevant across all different countries and immunization programme designs and validated by experts. Discussion: The identified use cases of seasonal influenza vaccines can support the optimization of vaccination programmes to increase their public health impact. The use cases identified through this work can help signal to policymakers the most important populations and delivery channels to increase the impact of seasonal influenza vaccination programmes and help estimate programmatic requirements necessary for the supportive policy recommendations. The use cases can also support the design of measures aimed at increasing access in low resource settings and coverage in settings where seasonal vaccines are widely used. The use cases can also help to inform the development, of improved influenza vaccines by highlighting the specific product characteristics relevant to their most impactful uses in different programmatic settings.