New Delhi, Nov. 11 -- Close to 31.5 million people in Karnataka are projected to have been infected by the Sars-CoV-2 virus, according to a seroprevalence study carried out by an independent group of researchers, which suggests the actual number of infections in the state could be close to 100 times higher than the 327,000-odd cases confirmed till August end. The research uses a survey design previously been utilised to gather detailed household econometrics. Sero prevalence studies, which involve drawing blood to determine presence of antibodies, typically require careful consideration in sampling in order to get a true picture in a given area....