A community-based sero-survey, conducted by the Indian Council of Medical Research (ICMR), to estimate the prevalence of SARS-CoV-2 infection in the population, is under way in Chennai.
Manoj Murhekar, Director, ICMR- National Institute of Epidemiology, Chennai, said the survey was ongoing in the city in randomly-selected wards.
Coordinated by the National Institute of Epidemiology and the National Institute for Research in Tuberculosis, Chennai, the national community-based sero-survey will involve the collection of venous blood samples from 400 randomly-selected individuals (one per household) from 10 clusters in each selected district, according to a press release from ICMR.
“It is a population-based survey. Samples will be collected from 24,000 individuals from 69 districts across the country that will include Coimbatore, Chennai and Tiruvannamalai in Tamil Nadu. In addition, the survey will be conducted from [COVID-19] containment zones of 10 cities, which are the high-burden cities having the highest number of cases. Another 5,000 samples will be collected from these 10 cities that include containment zones in Chennai,” he said.
The plan, he said, was to collect 29,000 samples from the 10 cities and 69 districts, test for IgG antibodies against COVID-19 using the ELISA kit developed by the National Institute of Virology, Pune. “The survey in Coimbatore and Tiruvannamalai in Tamil Nadu is complete. The survey in Chennai is ongoing. We have completed the survey in nearly 70% of the districts till date. We are likely to start testing by the weekend. The survey will tell us the extent of infection in the community in different areas,” Dr. Murhekar said.
“In addition to the 10 wards, we will also select five containment zones from Chennai,” he added.
He said a similar survey will be repeated. The decision for the next round of survey will be based on the results of this survey.
“Tamil Nadu is doing well in terms of testing. There are some wards where the infection is localised, and they need more focused activities, including testing symptomatics, contact tracing and isolation of positives,” he said
