Burden of typhoid fever in low-income and middle-income countries: a systematic, literature-based update with risk-factor adjustment
Background: No access to safe water is an important risk factor for typhoid fever, yet risk-level heterogeneity is unaccounted for in previous global burden estimates. Since WHO has recommended risk-based use of typhoid polysaccharide vaccine, we revisited the burden of typhoid fever in low-income...
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doaj-dac2153faff14f6499190e063fbc6c332020-11-25T01:45:41ZengElsevierThe Lancet Global Health2214-109X2014-10-01210e570e58010.1016/S2214-109X(14)70301-8Burden of typhoid fever in low-income and middle-income countries: a systematic, literature-based update with risk-factor adjustmentDr. Vittal Mogasale, PhD0Brian Maskery, PhD1R Leon Ochiai, DPhil2Jung Seok Lee, MS3Vijayalaxmi V Mogasale, MD4Enusa Ramani, MSc5Young Eun Kim, MS6Jin Kyung Park, PhD7Thomas F Wierzba, PhD8International Vaccine Institute, Seoul, South KoreaInternational Vaccine Institute, Seoul, South KoreaInternational Vaccine Institute, Seoul, South KoreaInternational Vaccine Institute, Seoul, South KoreaInternational Vaccine Institute, Seoul, South KoreaInternational Vaccine Institute, Seoul, South KoreaInternational Vaccine Institute, Seoul, South KoreaInternational Vaccine Institute, Seoul, South KoreaInternational Vaccine Institute, Seoul, South Korea Background: No access to safe water is an important risk factor for typhoid fever, yet risk-level heterogeneity is unaccounted for in previous global burden estimates. Since WHO has recommended risk-based use of typhoid polysaccharide vaccine, we revisited the burden of typhoid fever in low-income and middle-income countries (LMICs) after adjusting for water-related risk. Methods: We estimated the typhoid disease burden from studies done in LMICs based on blood-culture-confirmed incidence rates applied to the 2010 population, after correcting for operational issues related to surveillance, limitations of diagnostic tests, and water-related risk. We derived incidence estimates, correction factors, and mortality estimates from systematic literature reviews. We did scenario analyses for risk factors, diagnostic sensitivity, and case fatality rates, accounting for the uncertainty in these estimates and we compared them with previous disease burden estimates. Findings: The estimated number of typhoid fever cases in LMICs in 2010 after adjusting for water-related risk was 11·9 million (95% CI 9·9–14·7) cases with 129 000 (75 000–208 000) deaths. By comparison, the estimated risk-unadjusted burden was 20·6 million (17·5–24·2) cases and 223 000 (131 000–344 000) deaths. Scenario analyses indicated that the risk-factor adjustment and updated diagnostic test correction factor derived from systematic literature reviews were the drivers of differences between the current estimate and past estimates. Interpretation: The risk-adjusted typhoid fever burden estimate was more conservative than previous estimates. However, by distinguishing the risk differences, it will allow assessment of the effect at the population level and will facilitate cost-effectiveness calculations for risk-based vaccination strategies for future typhoid conjugate vaccine. Funding: Bill and Melinda Gates Foundation. http://www.sciencedirect.com/science/article/pii/S2214109X14703018 |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Dr. Vittal Mogasale, PhD Brian Maskery, PhD R Leon Ochiai, DPhil Jung Seok Lee, MS Vijayalaxmi V Mogasale, MD Enusa Ramani, MSc Young Eun Kim, MS Jin Kyung Park, PhD Thomas F Wierzba, PhD |
spellingShingle |
Dr. Vittal Mogasale, PhD Brian Maskery, PhD R Leon Ochiai, DPhil Jung Seok Lee, MS Vijayalaxmi V Mogasale, MD Enusa Ramani, MSc Young Eun Kim, MS Jin Kyung Park, PhD Thomas F Wierzba, PhD Burden of typhoid fever in low-income and middle-income countries: a systematic, literature-based update with risk-factor adjustment The Lancet Global Health |
author_facet |
Dr. Vittal Mogasale, PhD Brian Maskery, PhD R Leon Ochiai, DPhil Jung Seok Lee, MS Vijayalaxmi V Mogasale, MD Enusa Ramani, MSc Young Eun Kim, MS Jin Kyung Park, PhD Thomas F Wierzba, PhD |
author_sort |
Dr. Vittal Mogasale, PhD |
title |
Burden of typhoid fever in low-income and middle-income countries: a systematic, literature-based update with risk-factor adjustment |
title_short |
Burden of typhoid fever in low-income and middle-income countries: a systematic, literature-based update with risk-factor adjustment |
title_full |
Burden of typhoid fever in low-income and middle-income countries: a systematic, literature-based update with risk-factor adjustment |
title_fullStr |
Burden of typhoid fever in low-income and middle-income countries: a systematic, literature-based update with risk-factor adjustment |
title_full_unstemmed |
Burden of typhoid fever in low-income and middle-income countries: a systematic, literature-based update with risk-factor adjustment |
title_sort |
burden of typhoid fever in low-income and middle-income countries: a systematic, literature-based update with risk-factor adjustment |
publisher |
Elsevier |
series |
The Lancet Global Health |
issn |
2214-109X |
publishDate |
2014-10-01 |
description |
Background: No access to safe water is an important risk factor for typhoid fever, yet risk-level heterogeneity is unaccounted for in previous global burden estimates. Since WHO has recommended risk-based use of typhoid polysaccharide vaccine, we revisited the burden of typhoid fever in low-income and middle-income countries (LMICs) after adjusting for water-related risk.
Methods: We estimated the typhoid disease burden from studies done in LMICs based on blood-culture-confirmed incidence rates applied to the 2010 population, after correcting for operational issues related to surveillance, limitations of diagnostic tests, and water-related risk. We derived incidence estimates, correction factors, and mortality estimates from systematic literature reviews. We did scenario analyses for risk factors, diagnostic sensitivity, and case fatality rates, accounting for the uncertainty in these estimates and we compared them with previous disease burden estimates.
Findings: The estimated number of typhoid fever cases in LMICs in 2010 after adjusting for water-related risk was 11·9 million (95% CI 9·9–14·7) cases with 129 000 (75 000–208 000) deaths. By comparison, the estimated risk-unadjusted burden was 20·6 million (17·5–24·2) cases and 223 000 (131 000–344 000) deaths. Scenario analyses indicated that the risk-factor adjustment and updated diagnostic test correction factor derived from systematic literature reviews were the drivers of differences between the current estimate and past estimates.
Interpretation: The risk-adjusted typhoid fever burden estimate was more conservative than previous estimates. However, by distinguishing the risk differences, it will allow assessment of the effect at the population level and will facilitate cost-effectiveness calculations for risk-based vaccination strategies for future typhoid conjugate vaccine.
Funding: Bill and Melinda Gates Foundation.
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url |
http://www.sciencedirect.com/science/article/pii/S2214109X14703018 |
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