Seroprevalence of chikungunya virus infection in India 2017 a cross sectional population based serosurvey

Globally, 1·3 billion people living in 94 countries are estimated to be at risk of chikungunya virus (CHIKV) infection. There were no published reports of CHIKV during the period from 1974 to 2004. Very few CHIKV seroprevalence surveys have been reported from India. These surveys were either done over a limited geographical area,11–13 or immediately after CHIKV epidemics. Nationwide data for seroprevalence of CHIKV in India is absent. In this study, we aimed to estimate age-specific seroprevalence and the proportion of the population susceptible to CHIKV infection by testing serum samples of individuals aged 5–45 years for CHIKV, collected as part of a nationally representative dengue serosurvey in India.

We did a community-based survey in 240 clusters (118 rural, 122 urban), selected from 60 districts of 15 Indian states from 5 geographical regions. We enumerated each cluster, randomly selected (with an Andriod application developed specifically for the survey) 25 individuals from age groups of 5–8 years, 9–17 years, and 18–45 years, and sampled a minimum of 11 individuals from each age group (all the 25 randomly selected individuals in each age group were visited in their houses and individuals who consented for the survey were included in the study). Age was the only inclusion criterion; for the purpose of enumeration, individuals residing in the household for more than 6 months were included.