Sero-survey report indicates large sections of Indian population still susceptible

Published : June 11, 2020 22:31 IST

At a media briefing on COVID-19, (from left) Balram Bhargava, DG, ICMR; Lav Agarwal, Joint Secretary, Health; and K.S. Dhatwalia. Principal DG, Press Information Bureau, in March. Photo: PTI

Despite the growing number of infections and ranking fifth among countries with the largest number of COVID cases, there is, according to Dr Balram Bhargava, Director General of Indian Council of Medical Research (ICMR), no community transmission in India and 0.73 per cent of the general population has been infected by the virus. He made these observations to the media while releasing the results of the first part of a comprehensive serological survey of SARS CoV-2 in India conducted jointly by the ICMR, State health departments, the World Health Organisation (India) and the National Centre for Disease Control (NCDC).

The survey was conducted in the third week of May and covered a sample of 26,400 individuals and 28,595 households in 83 districts with the objective of ascertaining the infection spread in the general population. The DG, ICMR, said the survey tested for IgG antibodies and the results showed a very low prevalence of the infection. Only 0.73 per cent of the population in these districts was found IgG positive, that is, they had been infected with SARS CoV-2 in the past. The infection fatality rate was very low at 0.08 per cent.

This, he said, indicated that the lockdown and containment measures were successful and needed to continue as a large proportion of the population was still susceptible. The infection in containment zones was very high with significant variations, and estimating this forms the second part of the study which is ongoing. The risk of infection was 1.09 times higher in urban areas and 1.89 times higher in urban slums compared with rural areas.

Extrapolating 0.73 per cent

If the 0.73 per cent is extrapolated to the total population of the country, which is 1.36 billion, it would mean that close to 99 lakh (9.9 million) people have been infected in the country as a whole, which by any standards is not a small number. As of June 11, the Health Ministry reported a total of 2.87 lakh confirmed cases in the country, which is less than 3 per cent of the actual numbers that would be captured by testing as per the survey. The figure of 99 lakh infected people is consistent with the finding in the survey that the infection fatality rate is 0.08 per cent given the fact that 8,102 COVID-related deaths have been recorded in the country till June 11 (which is 0.08 per cent of 99 lakh).

The survey is perhaps the largest ever serological survey conducted by any country, according to V.K. Paul, Member, Niti Aayog, and Chair of the National Technical Group on COVID.

Joint Secretary (Health) Lav Agarwal emphasised that the recovery rate was at 49.12 per cent and that the "number of people recovered exceeded the number of active patients". He cautioned that a comparison in absolute numbers with other countries could be a "little misleading" and that comparisons ought to be made with countries with comparable populations. The cases per lakh population or even the deaths per lakh population in India was among the lowest in the world, said Agarwal sharing statistics that compared India with Western democracies and some Latin American countries where infections were spiking. He did not say that the tests in India were also among the lowest in the world.

To a question from Frontline on why the number of tests daily had plateaued (the average number of tests daily ranged between 1.25 and 1.5 lakh) when number of infections was going up, the DG, ICMR, replied that they had drastically ramped up testing facilities and had encouraged States to test more. Yet, he said, the capacity (of testing) was not fully utilised.

Mixed signals of "containment" success

Notwithstanding the "success" of the lockdown and containment strategy and a less than 1 per cent prevalence of infections, the government did not seem confident that the infection had been suppressed. The Health Ministry officials and the DG, ICMR, warned that infections could spread as a large proportion of the population was susceptible. Urban slums, they stressed, were highly vulnerable to infections. Local lockdown measures needed to continue as advised by the Central government even as non-pharmacological interventions such as physical distancing, use of mask, hand hygiene and cough etiquette remained in place.

The high-risk groups such as the elderly, those with chronic morbidities, pregnant women and children under 10 should be "protected". State governments would have to continue with "strong implementation of containment strategies" to contain and control of the spread of the virus, said the top-ranking government officials at the press briefing, indicating that the lowering of the guard was not an option at the moment.