Evaluating the impact and cost-effectiveness of typhoid conjugate vaccine schedules across diverse settings: A multi-model comparison
5 affiliations
- 1Department of Epidemiology of Microbial Diseases, Yale School of Public Health, Yale University, New Haven, Connecticut, United States of America.
- 2Institute for Disease Modeling, Gates Foundation, Seattle, Washington, United States of America.
- 3Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University, Stanford, California, United States of America.
- 4Burnet Institute, Melbourne, Victoria, Australia.
- 5Department of Performance, Finance and Delivery, World Health Organization, Geneva, Switzerland.
Abstract
Background: Given emerging evidence on the waning of immunity from typhoid conjugate vaccines (TCV), the World Health Organization (WHO) commissioned a multi-model comparison to determine the optimal schedule in terms of health and economic impact to inform updated recommendations for TCV use across different settings. Methods and findings: To identify optimal vaccination strategies across different incidence settings and vaccine waning assumptions, we compared two agent-based and two compartmental dynamic models of typhoid transmission. All models were fitted to harmonized age-specific incidence data from medium, high, and very high incidence settings. We assessed different TCV schedules under slow- and fast-waning scenarios to evaluate the best age for routine vaccination and the potential need for booster doses and catch-up campaigns. We evaluated the public health and economic impact predicted for each model and scenario using the net-monetary-benefit framework to determine cost-effectiveness under two representative scenarios for the health outcomes and costs of vaccination and treatment. Over a 10-year time horizon, routine vaccination at 9 months with a catch-up campaign to 15 years and a booster dose at 5 years was predicted to have the greatest impact, reducing cases by a median of 40%–68% across the incidence settings. Across all four models, TCV introduction with a catch-up campaign was cost-effective above willingness-to-pay (WTP) thresholds of $1,250 per disability-adjusted life-year (DALY) averted in medium incidence settings when costs of illness and case fatality risk (CFR) are high and in high incidence settings when costs and CFR are low. The optimal strategy was to delay vaccination to 2 or 5 years of age if waning is fast, depending on the age of peak incidence. In very high incidence settings, TCV introduction at 9 months or 2 years of age was cost-saving, and adding a booster dose at 5 years was cost-effective at most WTP values across all scenarios. The study findings are limited by the data available to inform indirect vaccine protection and other simplifying assumptions made in this analysis. Conclusions: Model predictions for the impact and cost-effectiveness of different TCV schedules were fairly robust to uncertainty in parameter values and model structure, but the optimal strategy depends on the typhoid incidence rate, CFR, and waning rate of vaccine protection. Why was this study done?: What did the researchers do and find?: What do these findings mean?: Catherine Wenger and colleagues perform a multi-model comparison to identify optimal strategies for typhoid vaccination under different rates of waning immunity and incidence levels.
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BibTeX
@article{wenger2026evaluating,
title = {{Evaluating the impact and cost-effectiveness of typhoid conjugate vaccine schedules across diverse settings: A multi-model comparison}},
author = {Catherine G C Wenger and Kyra H Grantz and Tigist F Menkir and Alina M Muellenmeister and Zeaan Pithawala and Raymond Hutubessy and Vittal Mogasale and Alicia N M Kraay and Nick Scott and Romesh G Abeysuriya and Jason R Andrews and Jillian Gauld and Nathan C Lo and Virginia E Pitzer},
journal = {PLOS Medicine},
year = {2026},
month = oct,
doi = {10.1371/journal.pmed.1005280},
url = {https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1005280},
note = {CC BY},
}
RIS
TY - JOUR
TI - Evaluating the impact and cost-effectiveness of typhoid conjugate vaccine schedules across diverse settings: A multi-model comparison
AU - Catherine G C Wenger
AU - Kyra H Grantz
AU - Tigist F Menkir
AU - Alina M Muellenmeister
AU - Zeaan Pithawala
AU - Raymond Hutubessy
AU - Vittal Mogasale
AU - Alicia N M Kraay
AU - Nick Scott
AU - Romesh G Abeysuriya
AU - Jason R Andrews
AU - Jillian Gauld
AU - Nathan C Lo
AU - Virginia E Pitzer
PY - 2026
DA - 2026/10/13
JO - PLOS Medicine
DO - 10.1371/journal.pmed.1005280
UR - https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1005280
AB - Background: Given emerging evidence on the waning of immunity from typhoid conjugate vaccines (TCV), the World Health Organization (WHO) commissioned a multi-model comparison to determine the optimal schedule in terms of health and economic impact to inform updated recommendations for TCV use across different settings. Methods and findings: To identify optimal vaccination strategies across different incidence settings and vaccine waning assumptions, we compared two agent-based and two compartmental dynamic models of typhoid transmission. All models were fitted to harmonized age-specific incidence data from medium, high, and very high incidence settings. We assessed different TCV schedules under slow- and fast-waning scenarios to evaluate the best age for routine vaccination and the potential need for booster doses and catch-up campaigns. We evaluated the public health and economic impact predicted for each model and scenario using the net-monetary-benefit framework to determine cost-effectiveness under two representative scenarios for the health outcomes and costs of vaccination and treatment. Over a 10-year time horizon, routine vaccination at 9 months with a catch-up campaign to 15 years and a booster dose at 5 years was predicted to have the greatest impact, reducing cases by a median of 40%–68% across the incidence settings. Across all four models, TCV introduction with a catch-up campaign was cost-effective above willingness-to-pay (WTP) thresholds of $1,250 per disability-adjusted life-year (DALY) averted in medium incidence settings when costs of illness and case fatality risk (CFR) are high and in high incidence settings when costs and CFR are low. The optimal strategy was to delay vaccination to 2 or 5 years of age if waning is fast, depending on the age of peak incidence. In very high incidence settings, TCV introduction at 9 months or 2 years of age was cost-saving, and adding a booster dose at 5 years was cost-effective at most WTP values across all scenarios. The study findings are limited by the data available to inform indirect vaccine protection and other simplifying assumptions made in this analysis. Conclusions: Model predictions for the impact and cost-effectiveness of different TCV schedules were fairly robust to uncertainty in parameter values and model structure, but the optimal strategy depends on the typhoid incidence rate, CFR, and waning rate of vaccine protection. Why was this study done?: What did the researchers do and find?: What do these findings mean?: Catherine Wenger and colleagues perform a multi-model comparison to identify optimal strategies for typhoid vaccination under different rates of waning immunity and incidence levels.
SN - 1549-1676
SN - 1549-1277
ER -