- Large number of infected persons asymptomatic, the survey indicated
- The decision came as the numbers of infected people dropped
- Government cautioned 77 per cent people are still vulnerable
Surveys to check the prevalence of coronavirus among the general population of Delhi will now be held every month, the state's health minister Satyendar Jain said today, announcing the beginning of the first of this series of surveys from August 1 to 5. The decision of the Delhi government came as the numbers of infected people dropped way below the last few weeks' average of 2,000, but a sero-survey indicated that at least one in five persons in Delhi had contracted the disease. The survey also indicated that a large number of infected persons remained asymptomatic, increasing the chances of the spread.
"The government has decided to conduct sero-survey every month to understand the spread of virus in the national capital," said Dr Satyendar Jain.
A sero-survey is where doctors test the blood of a section of the general population to check the presence of anti-bodies to any disease. Antibodies develop only when the person had contracted the disease in the past. It not only indicates how far among the general population the disease has spread, but whether the people are moving towards herd immunity.
The results of the last sero-survey held in Delhi indicated that six months into the pandemic, 23.48 per cent people had contracted coronavirus in the city, which has recorded more than 1.2 lakh cases so far. Both the government and experts cautioned that 77 per cent people are still vulnerable to the disease and all preventive measures still need to continue.
"More than 75 per cent of the people do not have antibodies. So we cannot be laid back in our approach," Dr Richa Sareen, a consultant at the Pulmonogy and Critical Care Medicine at Fortis Hospital, told NDTV.
"All measures of hygiene and social distancing need to continue. Everybody should still wear masks all the time and sanitise themselves. It has been observed in western countries that when cases decrease, people become lax and it leads to a second surge of cases. We have to prevent that kind of a situation in Delhi," she added.
Dr Jain, however, reminded that the survey gave the status of the city gave a status of the city till 15 June, since anti-bodies take 15 days to develop. This means there is a possibility that more people contracted the virus and recovered by now, he added.
Delhi has a population of nearly 2 crore. Eight out of Delhi's 11 districts have more than 20 per cent of sero prevalence, Dr Sujeet Kumar Singh of the National Centre for Disease Control Director said yesterday.
The study, which was conducted from June 27 to July 10 by the National Center for Disease Control (NCDC) in collaboration with the Delhi government, was one of the biggest, with a total of A total of 21,387 samples being tested. In the coming surveys, the researchers will take a bigger sample size, the health minister said.
On Tuesday evening, records showed Delhi had 1,349 new cases of coronavirus against Monday's 954. It took the total number of cases in the national capital to 1,25,096. With 27 deaths, the total number of fatalities stands at 3,690.