The Indian Council of Medical Research (ICMR) has released details regarding its second national serosurvey conducted from 17 August to 22 September 2020.
Balram Bhargava, Director-General at ICMR, said at the press briefing on 20 September, “Typically, one serosurvey is not good to answer any questions. You have to do serial serosurveys in similar districts to find out what is happening. This clearly shows that the lockdown and containment measures, as well as behavior change at the population level, has contributed and checked the spread of SARS-CoV-2. However, a large percentage is still unexposed and susceptibility to getting the infection exists and is real. Therefore, we have to continue with our measures.”
The second survey was conducted in the same 700 villages/wards from 21 states, but the only difference was that this time, individuals above the age of 10 were considered, acknowledging the risk of infection among the younger population.
The results shared during the briefing:
The DG also mentioned a few international figures, wherein the seroprevalence is estimated at 9.3% in the US, 2.8% in Brazil and 4.6% in Spain.
“Since a large proportion of the population is still susceptible, prevention fatigue is to be avoided and 5T strategy (Test, Track, Trace, Treat Technology) to be adhered,” he added.
Union health minister Harsh Vardhan also said on Sunday, 28 September that the ICMR’s second survey shows that the Indian population is still far from achieving herd immunity against coronavirus infection, thus underlining the need for following COVID appropriate behavior, reported The Times of India.
It’s important to note that antibody tests are not diagnostic tests but are used to check the prevalence of the infection in the general population. These surveys at best indicate the possible spread of the disease in the community and help authorities come up with better strategies. They show us the presence or absence of antibodies in a person - they do not tell us the amount, and they cannot identify if these are ‘neutralising’ antibodies (which specifically target the pathogen in concern).
According to the presentation made during the press briefing, serosurveys are expected to answer the following questions:
Associating the presence of antibodies to immunity against COVID-19 would be an overstretched link, experts believe. FIT had earlier reported on the danger of assuming herd immunity based on serosurvey results.
Dr K Srinath Reddy, President of Public Health Foundation of India (PHFI) had told FIT, “We do not know to what levels these antibodies will confer immunity or what duration that immunity will last. For instance, influenza immunity does not last long. We also need to know if we need cell immunity or whether these antibodies are enough.”
With reports of possible reinfections coming in from parts of the country and the world, following precautions and staying safe would still remain as crucial as ever.
(At The Quint, we are answerable only to our audience. Play an active role in shaping our journalism by becoming a member. Because the truth is worth it.)