The latest sero survey

  01-Oct-2020 13:51:58

Cronavirus Sero Surveys COVID-19 infection


The Indian Council of Medical Research(ICMR) has recently completed the second nation-wide serosurvey following the first one in May. The serosurvey is the process of testing the serum portion of the blood, which in layman’s term means, the liquid portion of the blood. The serum contains traces of the antibodies released by the body to fight infection. This enables researchers to spot a COVID infection even after the patient has recovered. This is not the case in normal testing from nostrils and mouth samples as they detect the virus only when there is an active infection. The serosurvey tests and accumulates data which will help guide the control measures. The findings were released on the 29th of September and here’s how ICMR director General Balram Bhargava puts it:


  • Of the 29,082 people tested from August 17 to September 22, 6.6 percent of the test subjects were exposed to the Covid-19 virus. The number is higher for adults, with 7.1 percent being exposed. These numbers show an alarming increase from the 0.73 percent of the May to June study.


  • The exposure was to be uniform across all age groups. This finding is in contrast to the previous assumptions that children were not affected as much.


  • The risk of COVID infection in urban slums(15.6%) is twice that of the urban non-slum(8.2%) areas and four times that of rural areas(4.4%).

  • A large portion of the population is still susceptible. Social distancing and face masks are still very much essential to control the transmission.

  • Over 90 percent of the population is still susceptible to the virus.

On extrapolation of the above figures to the overall population, almost 88 million people have supposedly been exposed to the Covid-19 virus. Though this survey is aimed towards formulating control strategies, experts suggest that these numbers do not paint a fair picture of the actual landscape. Dr Jugal Kishore, head of community medicine at Safdarjung Hospital, said that the survey data holds academic value but may not help in policymaking. This claim can be backed if we look at the May-June serosurvey, the results of which were published only in September, showed that 64 lakh people were already infected by May. The infection numbers are outdated with the majority of them developing antibodies. But the numbers do help in finding the flaw in the current strategy.

The survey results show that a large part of the infected population goes by untested and in some cases, is asymptomatic. This has been the most explicit fact from the survey result highlighting the glaring flaws in our current strategy. The survey has pointed out that depending on the appearance of symptoms as an indicator of infection is no longer dependable. The number of asymptomatic individuals posing as vectors is unknown and they are a threat to the control measures. Strict measures of social distancing, wearing face masks, and avoiding public spaces in all is the only valid solution. Relaxation of lockdowns can result in a second wave even before the first one passes.


By: Saajan

Cover image credit: AP