As per a latest eroprevelance survey in Hyderabad, around 54 per cent of the city’s residents have developed antibodies against SARS-CoV-2, indicating prior exposure to the coronavirus. As per a report in New Indian Express, the survey also revealed that more than 75 per cent of the seropositive population did not know they had contracted coronavirus infection in the past.
The study was jointly conducted by CSIR – Centre for Cellular and Molecular Biology (CCMB), ICMR – National Institute of Nutrition (NIN) and Bharat Biotech and it aimed at estimating the seroprevalence of antibodies against the coronavirus in Hyderabad. Over 9000 samples were checked for antibodies against the virus in people from across 30 wards of the city. At least 300 people from each ward, all of them older than 10 years of age, were tested during the survey.
Most of the wards showed a similarly uniform range of seroprevalence from 50-60 per cent, while few wards showed as much as 70 per cent or as low as 30 per cent seroprevalence as well.
Women showed a marginally higher seropositivity rate (56 per cent) than men (53 per cent). Among the senior citizens, 70 years of age showed a lower seropositivity (49 per cent).
Naturally, those who had Covid-19 positive cases in their own households, showed the maximum seropositivity of 78 per cent.
Dr A Laxmaiah, Scientist ‘G’ at the NIN, observed that having a larger number of rooms in houses and small family size households had low prevalence of coronavirus infection. Dr R Hemalatha, Director, NIN, said that this multistage random sampling study on 9000 people in the city of Hyderabad showed that more than 75 per cent of the seropositive population did not know that they had contracted coronavirus infection in the past. This suggests seroconversion, that is antibody formation has happened even with silent infections.
About 18 per cent of the group had been tested earlier and were found positive for the coronavirus. At least 90 per cent of them were found to be seropositive, suggesting that they retain the antibody response.
