Data from: Impact of the COVID-19 pandemic and TCV introduction on typhoid fever in Nepal

While typhoid conjugate vaccines (TCV) offer promise for reducing risk
in endemic settings, their population-level impact remains
unclear. In 2022, Nepal introduced TCV nationally on the heels of
the COVID-19 pandemic, which disrupted healthcare
services, surveillance, and potentially typhoid transmission
dynamics, complicating vaccine impact evaluation. We investigated
the impact of TCV introduction amid shifting typhoid burden
during the pandemic by analyzing blood culture data from four
Kathmandu Valley health facilities, comparing culture positivity
for Salmonella Typhi across three periods: pre-pandemic
(January 2018-March 2020); pandemic, pre-vaccine introduction
(April 2020-April 2022); post-vaccine introduction (May
2022-April 2024). S. Typhi blood culture positivity declined
sharply during the pandemic before TCV introduction. The
subsequent rollout of TCV substantially reduced typhoid burden in
vaccine-eligible children; however, rising cases among older,
vaccine-ineligible populations following the relaxation of
pandemic measures highlight the need for additional control measures, such
as improved water and sanitation infrastructure and broader age
eligibility for typhoid vaccination.