The exercise is crucial to find out if Delhi is heading towards herd immunity from the coronavirus. The last serological survey revealed that nearly a quarter of the population of the city has antibodies. Since then, the number of those recovered from Covid-19 has increased manifold.
“Blood samples are taken in serological surveys and are analysed to check the presence of antibodies. Samples testing positive reveal that the person was infected with Covid-19 and has recovered. When 24% people tested positive in the last survey, it was believed (by some people) that 24% tested positive for the disease. But it actually means that 24% people were exposed to Covid-19 and recovered,” health minister Satyendar Jain told mediapersons.
Jain said the government wants to check the difference in the prevalence of antibodies between the two surveys.
An official said that all samples were collected before 2pm and were sent to the laboratories before 4pm. Each district has been allocated two to three laboratories where the samples would be tested. “All samples have been provided with a unique identification and all documentation was also completed,” said an official.
The sero-survey will be carried out every month. The ongoing survey will finish by August 7. The areas for collecting samples were identified using a technical process to ensure collection of multi-stage systematic random and representative sampling as per the guidelines of the government.