Sharing the details during the weekly press briefing of the Union Health Ministry on on Tuesday, ICMR Director-General Balram Bharghav said that one in 15 individuals was exposed to Covid-19 by August.
In percentage terms, the national prevalence was found to be 6.6 per cent, a multifold increase from the first round when 0.73 per cent of the population was found to be exposed to SARS-CoV-2, the virus which causes Covid-19.
The findings also stated that 7.1 per cent of the adult population showed evidence of past exposure to Covid-19.
Similar to the first round of sero-survey, the worst-affected were those between the age group of 18 and 45 years, followed by those between 46 and 60 years, who had developed antibodies against the Covid-19.
The risk in urban slums was twice than that in non-slum areas and four times than the risk in rural settings. According to the findings, urban slums (15.6 per cent) and non-slum areas (8.2 per cent) had higher Covid-19 infection prevalence than the rural areas (4.4 per cent).
However, the spread of infection per case reported was reduced in the second round due to scaled up testing.
"The virus was found to be 26-32 infections per reported case by August (81-130 in May), underlining the effect of scaled up testing, tracking and treating strategy," the findings showed.
The second round of the sero-survey was also conducted in the same manner as the first. A total of 700 villages and wards in 70 districts in 21 states of the country were randomly sampled between August 17 and September 22 for the second round of the survey.
Bhargav also said that the 5T strategy (test, track, trace, treat, technology) will be adhered to since a large proportion of the population is still susceptible to the deadly virus.