At least 15-20% of the over 22,000 people tested randomly across the city as part of a serological survey have developed antibodies against COVID-19, according to officials.
The survey report being prepared by the National Centre for Disease Control (NCDC), which was supposed to be submitted to the Central government and Delhi government, was not submitted till 9 p.m. on Friday.
“The report is yet to be finalised and was not submitted today [Friday]. The seroprevalence could be less or more than 20%. The north-east district [one of the 11 districts] had shown around 25-30% seroprevalence and three other districts had shown above 15%,” an official source told The Hindu .
The official said that higher seroprevalence is a good sign as it means that a larger part of the population has developed antibodies against the virus and chances of them again contracting the virus are very low. Thus they can break the chain of transmission of the virus and reduce the spread of the disease.
“Assuming that it is actually 20% in all zones in the city and that the survey truly represents the city, the virus circulation will still continue for a couple of months more,” said Giridhara R. Babu, professor at Indian Institute of Public Health, Bengaluru.
The process
The serological survey was started on June 27 and 22,823 random blood samples were collected from people of different age groups and demographics. The blood samples were then tested in about 15 labs using antibody testing kits to understand whether the person was infected by the virus and developed antibodies against it.
A positive result would mean that the person has developed antibodies against the virus. So, a seroprevalence of 20% would mean that 20 out of 100 people tested have developed antibodies against the virus.
The serological survey is part of a ‘Revised COVID Response Plan’ decided by the Delhi government on June 22 based on the directions of the Union Ministry of Home Affairs on June 21.
