NEW DELHI: A sero-prevalance survey conducted in the first week of August in Delhi has found that 79 of the 257 people, who recovered from Covid- 19 and were part of the exercise, did not have antibodies against the virus. The sero survey was conducted by the Delhi government along with Maulana Azad Medical College from August 1-7 across all the 11 districts.
Blood samples of 257 people who had tested Covid-19 positive earlier and then recovered, were taken during the survey to test if they had antibodies. Antibodies were found in 29.1 per cent of people in the August sero-prevalence survey in the national capital, Delhi Health Minister Satyendar Jain had said while announcing its results.
Prevalence of antibodies found in males was 28.3 per cent, and in females 32.2 per cent. Out of total number of samples, 25 per cent were taken from the age group of less than 18 years, another 50 per cent from 18-49 years age bracket and remaining 25 per cent from those in the age group of 50 years or more, the Delhi health minister had said.
Among the people sampled, who had Covid-19 earlier and recovered but did not show antibodies during the survey might have had contracted the disease several months ago at the early stage of the infection. So, their antibodies (IgG) might have disappeared, experts said. In most cases, the memory cells would remember the virus and trigger an immune response if a person who has recovered from Covid-19 is again attacked by the virus.
On longevity of antibodies developed in response to Covid-19, Jain on August 20 had said, these antibodies can last for several months — say 5-8 months — but the body also produces T-cells in response to the infection. These T-cells, also called memory cells, help fight any possible infection again, and so, it is ‘very rare” that a person who has recovered from Covid-19 will be diagnosed with it again, the health minister had said.