Third serosurvey in Gurugram to check antibodies in vaccinated groups, kids

In its third Haryana-wide Covid -19 serological survey starting Wednesday, the state health department aims to study the level of antibodies in people fully inoculated against Covid-19

In its third Haryana-wide Covid -19 serological survey starting Wednesday, the state health department aims to study the level of antibodies in people fully inoculated against Covid-19. The survey will also have a different methodology compared to the two other surveys conducted last year when the vaccination drive had not been rolled out, said officials aware of the development.

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According to health officials, this will help them plan a targeted vaccination strategy and enhance their preparations for a possible third wave of Covid-19 infections.

A serological survey finds the level of antibodies in a given population that may have developed either after an infection or after being administered a dose of the vaccines.

Both the Indian Council of Medical Research (ICMR) and state governments conduct separate serological surveys.

Wednesday’s survey will cover children aged six to 17 years too for the first time. This is a population currently not covered under the Covid-19 immunisation programme.

“The study will analyse the percentage of antibodies developed in people, either through vaccination or by contracting the coronavirus infection. It will give an insight into the development of antibodies in people of all age groups,” said Dr Virender Yadav, Gurugram chief medical officer. Yadav on Tuesday attended the official launch of the survey by Haryana health minister Anil Vij over video conference.

Over 36,520 blood samples will be collected across the state, out of which about 3,600 would be from children aged six to nine years and about 11,000 from those between 10 and 17 years. The sample size is considerably higher than the 18,500 samples covered in the last survey held in October last year.

Over 2,200 medical staff across districts will conduct the survey and the results will be declared two weeks later, according to health officials.

In Gurugram, about 3,000 samples will be tested, of which at least 1,800 will be of adults.

According to state nodal officer for Covid-19, Dr Dhruva Chaudhry, the third round of the survey will follow a different strategy.

“The state has been divided into three zones based on the second serosurvey results. Districts that had less than 5% seropositivity are under the A zone. Districts with 5-15% seropositivity are in the B zone, while districts above 15% are under the C zone. The samples size will vary depending on the category and population,” he said.

The data will also have results from people who did not get infected but had got both shots of a vaccine, he said.

“It will help to estimate the percentage of adult population who remained asymptomatic but developed antibodies after vaccination. These multiple aspects will assist in planning a strategy to focus upon clusters for vaccination and to fine-tune our preparedness for the third wave of Covid-19,” said Dr Dhruva Chaudhry.

He hinted that a phase-2 of the study to understand the post-Covid 19 symptoms in the population could be in the works.

In the first state survey in August 2020, the state showed a seropositivity of 8%, while the second round had a positivity of 14.8%. Gurugram in the first round had a seropositivity of 18.5% and 5.7% in the urban and rural population, respectively, in the first survey. In the second round, the district had a 25.9% seropositivity in the urban sector, while it was 10.1% in the rural sector.

Till Tuesday, the state had administered over 17.3 million doses.