“…Three of the thirty selected clusters in Dibrugarh, Assam could not be completed due to the COVID-19 pandemic. Sample size was estimated for the overall serosurvey conducted in these districts, assuming rubella seroprevalence of 50 % among both the younger and older age groups, with an absolute precision of 10 %, a design effect of 2, and a 95 % confidence level [15] .…”