The Delhi government conducted the second serological survey in the capital on August 20 which revealed that nearly a third of Delhi's population or 58 lakh people have been exposed to COVID-19 and have developed antibodies.
A serological survey helps assess the exposure of a population to a virus or an infection. Blood samples are collected from respondents and are tested for antibodies. Even those people who were asymptomatic and may have recovered on their own can be detected in the survey.
"29.1 percent prevalence of the virus has been found in the second serosurvey," Delhi Health Minister Satyendar Jain said.
For the second sero-survey, a sample size of 15,000 was collected from 11 districts.
The highest prevalence was found in the southeast district with 33.2 per cent, a massive spike from the previous survey. The least number of cases has been recorded in the New Delhi area (24.6 per cent).
"Scientists say that herd immunity is when up to 40 per cent of the population has virus antibodies," Jain said, adding that those who had antibodies after being infected by the virus would be protected for six to eight more months.
"The antibodies will stay for six to eight months as per scientists," the minister said, who recently recovered from the deadly virus.
In the first serological survey conducted last month, 23.48 per cent of Delhi's population was found to have been exposed to the virus. The other two rounds are scheduled in the first weeks of September and October.