Assessing The Medium Term Impact Of A Vi-Polysaccharide Conjugate Vaccine In Preventing Typhoid Infections Among Nepali Children (TyVOID)

Chief Investigator
Sir Professor Andrew Pollard

Principal Investigator
Associate Professor Buddha Basnyat

Duration
September 2021 – now

This study is a continuation of the typhoid vaccine study (TyVAC Nepal), which aims to assess the medium-term efficacy of the Typhoid Conjugate Vaccine (TCV) in children by comparing the relative risk of typhoid fever in a TCV cohort initially vaccinated in 2017/2018 with TCV cohorts vaccinated in 2020 and 2021.

TyVOID Nepal is a prospective cohort study, alongside the continuation of a community surveillance study, which will include conducting healthcare facility-based passive surveillance for typhoid fever in vaccinees and non-vaccinees, immunogenicity study of children to assess waning immunity to Vi-TCV and WASH surveys along with a demographic census.

A qualitative component to assess the perception of the community regarding TCV vaccination will be conducted in parallel. All the participants who were enrolled in the initial TyVAC study will be eligible for inclusion in this study. The entire population within a selected geographical catchment area of Lalitpur, Kathmandu (17 wards of Lalitpur) will be included in the background typhoid surveillance and WASH assessment.