New Delhi: Delhi has 29.1 per cent seroprevalence and the national capital is yet to achieve herd immunity levels, according to findings of the second serological survey conducted in the city earlier this month.
Announcing the results here Thursday, Health Minister Satyender Jain said the sero survey report after calculating total seroprevalence along with sensitivity levels shows 28.35 per cent of prevalence in the national capital.
He added that 32.2 per cent of women in the capital showed seroprevalence as compared to just 28.3 per cent among men. Calling women the “stronger gender”, Jain said higher seroprevalence in women shows many of them didn’t even realise they fell ill, and recovered without intervention.
The minister clarified that this does not mean Delhi has reached herd immunity.
“It is good that nearly 29 per cent people have recovered and developed antibodies, which is higher than the 23 per cent in the first survey, but herd immunity is reached somewhere between 40-70 per cent,” Jain told the media.
Serological surveys are an exercise aimed at detecting the true exposure of a population to a disease. They involve testing blood samples for antibodies and thus help detect even those people who may have recovered from the disease on their own without requiring medical assistance. In the case of Covid-19, this would include asymptomatic patients who unknowingly contracted and recovered from the disease.
The survey
Conducted between 1 August and 7 August, the second serological survey covered 11 districts across Delhi and collected 15,000 samples.
As reported by ThePrint Wednesday, Jain said the South East district had maximum seroprevalence at 33 per cent while the least is in South West district at 12.95 per cent.
Defence Colony, Kalkaji and Sarita Vihar make up South East district while Dwarka, Vasant Vihar, Janakpuri , Najafgarh , Kapashera and Delhi Cantonment are all part of South West district.
“North east district has shown 29 per cent, south 27 per cent, south east 33 per cent,” he said.
Talking about the major observations in the second survey, a senior health official said that the margin among districts, as far as the infection level is concerned, has reduced as opposed to the previous sero survey.
The latest survey shows a 50.09 per cent increase in seroprevalence in the South East district, from 22.12 per cent in the first round to 33.2 per cent now. There has also been a 46.21 per cent rise in seroprevalence at South district, from 18.67 per cent in the first round to 27.2 per cent now.
As for age demographics, the survey has found maximum seroprevalence in those below 18 years of age (34.7 per cent), followed by those above 50 years of age (31.2 per cent). The 18-49 years age bracket showed 28.5 per cent seroprevalence.
The report also highlighted that it was ensured that the samples taken during the survey were not from people covered in the previous sero survey, and they won’t be included in the forthcoming one either. While the government is yet to finalise the sample size for the next sero survey to be conducted from 1 September, Jain said it will be looked into soon.
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