Typhoid conjugate vaccine perceptions and coverage among children and adults: Findings from a post-campaign coverage survey - Harare, Zimbabwe, 2019

Abstract

Background: In 2019, following a large outbreak of typhoid fever, the Zimbabwe Ministry of Health and Child Care conducted a typhoid conjugate vaccine (TCV) vaccination campaign in nine high-risk suburbs of Harare. We aimed to evaluate TCV vaccination coverage, vaccine perceptions, and adverse events reported after vaccination.

Methods: We conducted a two-stage cluster survey to estimate vaccination coverage in the campaign target areas among children aged 6 months-15 years and to classify coverage as either adequate (≥75 % coverage) or inadequate (<75 % coverage) among adults aged 16-45 years in one suburb. Questionnaires assessed socio-demographic factors, TCV vaccination history, reasons for receiving or not receiving TCV, adverse events following immunization, and knowledge and attitudes regarding typhoid and TCV.

Results: A total of 1,917 children from 951 households and 298 adults from 135 households enrolled in the survey. Weighted TCV coverage among all children aged 6 months-15 years was 85.3 % (95 % CI: 82.1 %-88.0 %); coverage was 74.8 % (95 % CI: 69.4 %-79.5 %) among children aged 6 months-4 years and 89.3 % (95 % CI: 86.2 %-91.7 %) among children aged 5-15 years. Among adults, TCV coverage was classified as inadequate with a 95 % confidence interval of 55.0 %-73.1 %. Among vaccinated persons, the most reported reason for receiving TCV (96 % across all age groups) was protection from typhoid fever; the most common reasons for non-vaccination were not being in Harare during the vaccination campaign and not being aware of the campaign. Adverse events were infrequently reported in all age groups (10 %) and no serious events were reported.

Conclusions: The 2019 TCV campaign achieved high coverage among school-aged children (5-15 years). Strategies to increase vaccination coverage should be explored for younger children as part of Zimbabwe's integration of TCV into the routine immunization program, and for adults during future post-outbreak campaigns.

Keywords: Disease outbreaks; Typhoid fever; Vaccination coverage; Vaccines, conjugate; Zimbabwe.