Chennai: Around seven per cent of India’s population aged ten and above was exposed to SARS-CoV-2, amounting to an estimated 74.3 million infections by August, with the seroprevalence being highest in urban slum areas followed by urban non-slum and rural areas, as per the findings of ICMR’s second national serosurvey.
The findings which have appeared in the Lancet Global Health pre-print said that the overall seroprevalence of below 10 per cent in India indicates that a large proportion of the population remains susceptible to novel coronavirus infection.
According to the report, the transmission of infection is expected to continue in most Indian states till the herd immunity threshold is achieved, either by natural infection or vaccination. While this threshold is unknown, most estimates place it above 50 per cent.
It further said that one in nine individuals who did not report any Covid-19-related symptoms in the past had the presence of SARS-CoV-2 IgG antibodies, indicating asymptomatic seroconversion among the general population in India.
Seroconversion was also documented among individuals without a history of known contact with a Covid-19 case, and among those without any prior SARS-CoV-2 testing.