More than half of Hyderabad’s population now has antibodies against Covid-19..
In a joint effort, CSIR-Centre for Cellular and Molecular Biology (CCMB), ICMR-National Institute of Nutrition (NIN) and Bharat Biotech have 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. “The study brings a comprehensive perspective of potentially protective immune response against the coronavirus in the city’s population,” Rakesh Mishra, Director, CCMB told newspersons at a press conference here on Thursday.
“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,” he added.
Scientists checked for antibodies against the virus in people across 30 wards of the city. Over 300 individuals, from each ward, all of them older than 10 years, were tested. Most of the wards showed a similarly uniform range of seroprevalence, of 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 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.
Unsurprisingly, 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). A Laxmaiah, Scientist ’G’ at NIN observed that those in houses with a larger number of rooms and small family size households had low prevalence of coronavirus infection.
This study also showed that more than 75 per cent of the seropositive population did not know that they had contracted coronavirus infection. “This suggests seroconversion, that is antibody formation has happened even with silent infections,” said R Hemalatha, Director, NIN. According to the study, individuals who had suffered the prominent Covid-19 symptoms as well as those who were asymptomatic, had equivalent seroprevalence of around 54 per cent. About 18 per cent of the study group had been tested earlier and found positive for the coronavirus while 90 per cent was found to be seropositive, suggesting that they retain the antibody response.