TY - JOUR
T1 - From Crisis to Control
T2 - A Study of Typhoid Conjugate Vaccine Efficacy in Harare, Zimbabwe (2017–2024)
AU - Bvochora, Talent
AU - Manyara, John
AU - Thilliez, Gaetan
AU - Vere, Michael
AU - Mukeredzi, Innocent
AU - Nhamo, Denford
AU - Chitiyo, Farai
AU - Muzondo, Augustine
AU - Juru, Agnes
AU - Chonzi, Prosper
AU - Phiri, Isaac
AU - Smith, Anthony M.
AU - Chaibva, Blessmore V.
AU - Mapingure, Munyaradzi
AU - Fuller, Walter
AU - Shrestha, Pramila
AU - Nair, Parvati
AU - Kingsley, Robert A.
AU - Laxminarayan, Ramanan
AU - Musuka, Godfrey
AU - Mashe, Tapfumanei
N1 - Publisher Copyright:
© The Author(s) 2026. Published by Oxford University Press on behalf of Infectious Diseases Society of America. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
PY - 2026/3
Y1 - 2026/3
N2 - Background: Typhoid fever remains a public health concern in Harare City, Zimbabwe. Recurrent outbreaks are driven by inadequate water, sanitation, and hygiene infrastructure. In 2019, the typhoid conjugate vaccine (TCV) was introduced. The TCV impact on typhoid epidemiology, antimicrobial resistance (AMR), Salmonella Typhi population, and effectiveness across districts and age groups remains understudied. Methods: Data from 3401 typhoid cases during 2017–2024 were analyzed. Attack rates, risk ratios, AMR, and vaccine effectiveness across prevaccine (2017–2019) and postvaccine (2020–2024) periods were compared. Analysis was stratified by district, vaccination coverage, and age groups. Genomic characteristics of Salmonella Typhi strains isolated postvaccination were investigated and compared to prevaccine populations. Results: Attack rates for the Western district, which reported 70.8% of cases, decreased from 1373/100 000 before TCV to 341/100 000 after (risk ratio: 0.40, P ≤ .0001). Subdistricts had attack rates of 1783 (Glen View), 1687 (Mufakose), and 1145 (Budiriro) per 100 000 before vaccination and 223, 33, and 364/100 000, respectively, after (risk ratio: 0.22, 0.03, 0.48, respectively, P < .0001). The 0–15 age group showed vaccine effectiveness of 81.2% (95% confidence interval, 71.2–88.8), compared to 61.4% (95% confidence interval, 54.3–68.1) across all ages. Genomic comparison of Salmonella Typhi isolates pre- and postvaccination did not indicate changes in bacterial population. AMR phenotypic data and genomic prediction indicated lower resistance to antibiotics postvaccination. Conclusions: TCV reduced typhoid incidence, particularly in high-burden areas and children. No shift in the Salmonella Typhi population was observed. Ongoing transmission underscores need for integrated measures, including human-resource capacity, improved water, sanitation, and hygiene infrastructure, research on vaccine performance variability, and refined multisectoral interventions.
AB - Background: Typhoid fever remains a public health concern in Harare City, Zimbabwe. Recurrent outbreaks are driven by inadequate water, sanitation, and hygiene infrastructure. In 2019, the typhoid conjugate vaccine (TCV) was introduced. The TCV impact on typhoid epidemiology, antimicrobial resistance (AMR), Salmonella Typhi population, and effectiveness across districts and age groups remains understudied. Methods: Data from 3401 typhoid cases during 2017–2024 were analyzed. Attack rates, risk ratios, AMR, and vaccine effectiveness across prevaccine (2017–2019) and postvaccine (2020–2024) periods were compared. Analysis was stratified by district, vaccination coverage, and age groups. Genomic characteristics of Salmonella Typhi strains isolated postvaccination were investigated and compared to prevaccine populations. Results: Attack rates for the Western district, which reported 70.8% of cases, decreased from 1373/100 000 before TCV to 341/100 000 after (risk ratio: 0.40, P ≤ .0001). Subdistricts had attack rates of 1783 (Glen View), 1687 (Mufakose), and 1145 (Budiriro) per 100 000 before vaccination and 223, 33, and 364/100 000, respectively, after (risk ratio: 0.22, 0.03, 0.48, respectively, P < .0001). The 0–15 age group showed vaccine effectiveness of 81.2% (95% confidence interval, 71.2–88.8), compared to 61.4% (95% confidence interval, 54.3–68.1) across all ages. Genomic comparison of Salmonella Typhi isolates pre- and postvaccination did not indicate changes in bacterial population. AMR phenotypic data and genomic prediction indicated lower resistance to antibiotics postvaccination. Conclusions: TCV reduced typhoid incidence, particularly in high-burden areas and children. No shift in the Salmonella Typhi population was observed. Ongoing transmission underscores need for integrated measures, including human-resource capacity, improved water, sanitation, and hygiene infrastructure, research on vaccine performance variability, and refined multisectoral interventions.
KW - Harare
KW - antimicrobial resistance
KW - attack rates
KW - effectiveness
KW - typhoid vaccination
UR - https://www.scopus.com/pages/publications/105041018443
UR - https://www.scopus.com/pages/publications/105041018443#tab=citedBy
U2 - 10.1093/ofid/ofag091
DO - 10.1093/ofid/ofag091
M3 - Article
C2 - 41873408
AN - SCOPUS:105041018443
SN - 2328-8957
VL - 13
JO - Open Forum Infectious Diseases
JF - Open Forum Infectious Diseases
IS - 3
ER -