Around 54 per cent of people in Hyderabad have antibodies against Coronavirus, reveals a joint survey by CSIR-Centre for Cellular and Molecular Biology (CCMB), ICMR-National Institute of Nutrition (NIN) and Bharat Biotech.
The joint effort estimated the seroprevalence of antibodies against the coronavirus SARS-CoV-2 in the city.
This study of around 9,000 samples, finds that around 54 per cent of Hyderabadis show antibodies against SARS-CoV-2, indicating prior exposure to the coronavirus.
“This study brings a comprehensive perspective of potentially protective immune response against the coronavirus in the city’s population. The data indicates that the population of Hyderabad might be slowly moving towards herd immunity, which will be certainly accelerated by the ongoing vaccination effort,” Dr Rakesh Mishra, Director, CCMB told a news conference.
Scientists checked for antibodies against the virus in people across 30 wards of the city. At least 300 people, from each ward, all of them older than 10 years of age, were tested.
Most of the wards showed a similarly uniform range of seroprevalence, from 50-60 per cent. However, a few wards showed as much as 70 per cent or as low as 30 per cent as well.
Women showed a marginally higher seropositivity rate (56 per cent) than the men (53 per cent). Those above 70 years of age showed a lower seropositivity (49 per cent), perhaps because of limited mobility and extra care taken by older individuals during the pandemic.
Those who had Covid-19 positive cases in their own households, showed the maximum seropositivity of 78 per cent. This was followed by those with known Covid-19 contacts outside their household (68 per cent).
Dr A Laxmaiah, Scientist ‘G’ at NIN observed that having a larger number of rooms in houses and small family size households had low prevalence of coronavirus infection.
“This multistage random sampling study on 9,000 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,” said Dr R Hemalatha, Director, NIN.
According to the study, individuals who had suffered the prominent Covid-19 symptoms as well as those who were asymptomatic, both had equivalent seroprevalence of around 54 per cent.
Eighteen per cent of the study group had been tested earlier and found positive for the coronavirus. Ninety per cent of them were found to be seropositive, suggesting that they retain the antibody response.