Programmatic Effectiveness of a Pediatric Typhoid Conjugate Vaccine Campaign in Navi Mumbai, India

Abstract

Background: The World Health Organization recommends vaccines for prevention and control of typhoid fever, especially where antimicrobial-resistant typhoid circulates. In 2018, the Navi Mumbai Municipal Corporation (NMMC) implemented a typhoid conjugate vaccine (TCV) campaign. The campaign targeted all children aged 9 months through 14 years within NMMC boundaries (approximately 320 000 children) over 2 vaccination phases. The phase 1 campaign occurred from 14 July 2018 through 25 August 2018 (71% coverage, approximately 113 420 children). We evaluated the phase 1 campaign's programmatic effectiveness in reducing typhoid cases at the community level.

Methods: We established prospective, blood culture-based surveillance at 6 hospitals in Navi Mumbai and offered blood cultures to children who presented with fever ≥3 days. We used a cluster-randomized (by administrative boundary) test-negative design to estimate the effectiveness of the vaccination campaign on pediatric typhoid cases. We matched test-positive, culture-confirmed typhoid cases with up to 3 test-negative, culture-negative controls by age and date of blood culture and assessed community vaccine campaign phase as an exposure using conditional logistic regression.

Results: Between 1 September 2018 and 31 March 2021, we identified 81 typhoid cases and matched these with 238 controls. Cases were 0.44 times as likely to live in vaccine campaign communities (programmatic effectiveness, 56%; 95% confidence interval [CI], 25% to 74%; P = .002). Cases aged ≥5 years were 0.37 times as likely (95% CI, .19 to .70; P = .002) and cases during the first year of surveillance were 0.30 times as likely (95% CI, .14 to .64; P = .002) to live in vaccine campaign communities.

Conclusions: Our findings support the use of TCV mass vaccination campaigns as effective population-based tools to combat typhoid fever.

Keywords: Salmonella Typhi; India; global health; typhoid fever; vaccines.

Figure 1.

Map of vaccine campaign communities (blue stripes) and delayed campaign communities (yellow solid) as demarcated by the borders of Navi Mumbai Municipal Corporation's 22 UHPs. Hospitals that participated in healthcare facility blood culture surveillance marked by green circles. Abbreviation: UHP, urban health post. The map was generated using data collected from ArcGIS Collector (Mobile application) and compiled using the desktop application and ArcGIS World Imagery and Light Canvas basemaps (Professional version, ESRI). Source credits for satellite imagery: Esri, DigitalGlobe, GeoEye, i-cubed, USDA FSA, USGS, AEX, Getmapping, Aerogrid, IGN, IGP, swisstopo, and the GIS User Community, DeLorme, HERE, MapmyIndia.

Figure 2.

Flow diagram depicting total estimated eligible participant population in Navi Mumbai (approximately 320 000), number of participants reported by healthcare facility blood culture surveillance (4602), number of participants with complete records (2953), number of participants included in analysis after matching (319), and blood culture–positives and blood culture–negatives included in analysis.