Majority of Indians have Covid-19 antibodies but study shows it’s not enough

While a majority of Indians have antibodies against the new coronavirus, vaccinations and Covid-19 precautions are the only way out of the pandemic, experts say.

Two-thirds of Indians over the age of 6 have had Covid-19 antibodies, according to the results of the fourth national serological survey conducted by the country’s leading medical body, the Indian Council for Medical Research (ICMR).

The survey was conducted across the country in June and July. Its results are significant because it is for the first time that children aged 6 to 17 have been included.

If extrapolated, that would mean that around 900 million people have been infected with the virus. The survey suggests that around 400 million of the country’s 1.3 billion and over people are still vulnerable.

Experts warn, however, that this should not give way to complacency as serological surveys are not an accurate barometer due to the fact that variants of the virus are constantly changing.

No room for complacency
“There is a silver lining, but there is no room for complacency. There is always a need to maintain appropriate behavior at Covid and limit community engagement, ”said ICMR Balram Bhargava.

This time, he found that the seropositivity among minors was very high at 57.2% in the 6-9 age group. Among 10-17 year olds it was 61.6%, while among healthcare workers it was 85.2%. In addition, seropositivity in unvaccinated people was found to be around 62%.

“As for the children, the children were infected, but it was very benign. Only isolated cases of infection can occur in children during the next wave of Covid-19, ”said VK Paul, head of the Covid working group.

Southern state of Kerala had the lowest exposure to Sars-Cov-2, according to true infection estimates based on serological studies, new government data showed on Wednesday, with only 44% of the population believed to have been infected until the beginning. in July against nearly 67% in the whole country.

“What this means is that the second wave will continue in Kerala for some time and a high number of new cases will be reported,” said Dr Sanjay Rai, head of the community medicine department at All India. Institute of Medical Sciences.

Uneven spread of infection
However, epidemiologists and scientists warn that these serological studies are not always reliable and credible because they were sample surveys where the methodology was not the same and the test kits were not always the same.

The uneven spread of infection complicates the task of sampling a population. Experts say the timing, choice of antibody test, and sampling methodology can have huge effects on results.

Scientists also argue that there is a need for more information at the district level, as well as information on re-infections and vaccine escapes, if strategies are to assess the impact of Covid-19 in the future.

For example, the capital Delhi alone has had five serological surveys. But there was no transparency in the results and different antibody tests and sampling approaches were used in the surveys.

According to data from the Ministry of Health, the total number of Covid-19 cases stands at over 3.14 million with the death toll at over 420,000. The country has reported less than 50,000 new infections in over the past month, with the situation improving since May, after the second wave ravaged the country.

However, scientists warn that overestimating the prevalence of antibodies in a country’s population does not automatically mean that herd immunity has been achieved.

Collective immunity is a term applied to the observation that not everyone in the population needs to be vaccinated against a disease for protection to extend to everyone, only a sufficiently large fraction known. under the name of threshold.

Recent studies have shown that despite the high seroprevalence in the UK and Israel for example, cases are still on the rise.

Seroprevalence data from across the country has deepened the understanding of the Covid-19 epidemic in India, but given that a large portion of the country’s population is unvaccinated, this could still create a perfect set of conditions for the emergence of new variants.