In general terms, it means that 66 lakh of the two crore Delhiites were infected with the novel coronavirus and now carry antibodies after their successful recovery. This would also be the highest seroprevalence since the outbreak of the pandemic.
The second survey conducted in the first week of August showed the prevalence of Covid-19 antibodies in 29.1% of the population, up from 23.4% in the first serological study that was conducted from June end to early July. While 15,000 samples were collected for the second survey, over 21,000 samples were gathered in the first one.
Describing it as a good sign, an official said, “People who have antibodies are not currently infected. They have recovered from Covid-19. Many of them didn’t even realise that they had been infected and recovered successfully.”
The samples are being analysed by Maulana Azad Medical College, which also conducted the first two surveys. A source said that over half the samples had been analysed and the percentage of antibodies prevalence could increase slightly when the final report was released. The latest prevalence of antibodies in people would help the government micro-analyse the Covid situation and take steps for containment of the virus.
Samples were collected from three categories — aged below 18, between 18 and 49 years, and above 50 years. The highest percentage of samples was collected from the 18-49 age group.
The survey was launched on the first day of the month and samples were collected by front line health workers by September 7. The teams mostly selected residents of identified locations through a randomised sampling technique. Such people were asked to visit the nearest dispensary and give their blood samples. Those covered in the first two surveys were excluded from the third one.
Delhi government is likely to sanction another survey from October 1 to assess the prevalence of antibodies next month too. The growth in antibodies indicates that Delhi is inching towards herd immunity against Covid-19. Data of all surveys would be analysed to devise and change strategies to combat the virus.