Field Effectiveness of a Typhoid Conjugate Vaccine: The 2018 Navi Mumbai Pediatric TCV Campaign

Area of Science:

• * Public Health and Tropical Medicine
• * Vaccinology and Infectious Disease Epidemiology

Background:

• * Typbar-TCV®, a typhoid conjugate vaccine (TCV), received WHO prequalification in 2017.
• * Typhoid fever remains a significant public health concern, particularly in endemic regions.

Purpose of the Study:

• * To evaluate the real-world effectiveness of Typbar-TCV® in a mass vaccination campaign.
• * To assess TCV's impact on laboratory-confirmed typhoid cases in children aged 9 months to 14 years.

Main Methods:

• * A case-control study was conducted in Navi Mumbai, India, from September 2018 to July 2020.
• * Compared typhoid cases with age-matched community controls, analyzing vaccination status.
• * Laboratory-confirmed typhoid cases were identified across six clinical sites.

Main Results:

• * Vaccine effectiveness (VE) against typhoid fever was calculated at 83.7% (95% CI: 45.0-95.3).
• * Only 8.6% of typhoid cases had received the TCV campaign vaccine, versus 37% of controls.
• * The adjusted odds ratio for typhoid fever in vaccinated children was 0.16 (95% CI: 0.05-0.55).

Conclusions:

• * Typbar-TCV® demonstrated robust effectiveness in a large-scale public sector vaccine introduction.
• * Real-world effectiveness aligns with findings from previous randomized controlled trials.
• * The study provides reassurance for policymakers regarding TCV's efficacy in public health programs.