Kids, adults have similar antibodies: AIIMS Sero Survey

The seroprevalence, presence of virus-fighting antibodies against Sars-CoV-2, among children was 55.7% across five study sites, in comparison to 63.5% among adults -- the difference was judged to be statistically insignificant.

The exposure of children to Covid-19 has been similar to adults’, a serological surveillance study spearheaded by the All India Institute of Medical Sciences (AIIMS) has found, addressing fears that a third wave of Covid-19 could disproportionately affect children.

In Delhi, which was one of the five sites for the study, the researchers found that 74.7% of the population – both children and adults – had been exposed to the infection.

The seroprevalence, presence of virus-fighting antibodies against Sars-CoV-2, among children was 55.7% across five study sites, in comparison to 63.5% among adults -- the difference was judged to be statistically insignificant.

In Delhi, which was one of the five sites for the study, the researchers found that 74.7% of the population – both children and adults – had been exposed to the infection. This is much higher seroprevalence that the state government’s survey from January where 56.1% were found to have antibodies against the virus. The samples for the AIIMS study were collected between April and May, and would not have detected antibodies of those who got the infection during the second wave.

There was also an urban-rural divide in prevalence in Delhi-NCR.

As compared to the 74.7% in urban settlements of South Delhi, the prevalence was 59.3% in villages of Delhi and Ballabhgarh. “Results show that a large majority of the population had already been infected by the time we conducted the study at Delhi urban site which belongs to lower and middle socioeconomic strata population and very congested neighbourhood,” the study said. With all locations other than Delhi being rural, the average seroprevalence in rural areas stood at 58.8% as per the study.

The highest seroprevalence was found in Gorakhpur, Uttar Pradesh where 87.9% of the people had been exposed to the infection.

More importantly, the seroprevalence among children and adults in the same regions were similar.

“Wherever the prevalence of antibodies was high among the adults, it was high among the children, busting the myth that so far children have been less affected. The thing is, the binding of the virus to the human cell receptors is not very good in children and hence they mostly develop either asymptomatic or mildly symptomatic infection,” said Dr Sanjay Rai, one of the authors of the study and the head of the department of community medicine at the AIIMS.

He added, “People have been saying that after the young, the third wave will impact children more. The fact is most of them have been already exposed to the infection along with their families. And, numerous studies have now shown that natural infection can provide better and longer protection against a second infection.”

The data for 4,509 study participants was collected between March and June of this year.