Kolkata: Covid antibodies found in 50% kids screened for vax trial

KOLKATA: About 50% of the volunteers at a Covid vaccine clinical trial for children at the Institute of Child Health (ICH) Kolkata were recently deemed ineligible for the study.
The reason: they already had Covid antibodies, indicating that they were infected by the Covid virus at some point but remained asymptomatic or escaped with mild symptoms. The exercise, however, was not a sero survey but a chance detection during a mandatory screening of potential participants before enrolling them for the vaccine trial.
Health experts say such data brings hope against the apprehension of a third wave where children are expected to be the most vulnerable.
The institute at Park Circus, one of the oldest referral hospitals for children in India, was selected as one of the sites for the phase 3 clinical trial of Zydus Cadila’s ZyCov-D vaccine on children between 12 and 18 years of age. As part of a pan-India study, the Kolkata institute had aimed to enrol 100 volunteers.
“About 50% of the children who were brought for the vaccine trial tested positive for Covid antibody. This means these children were unknowingly infected by the virus and have developed natural immunity. So, we had to keep them out of the trial,” said ICH professor Jaydeep Choudhury, co-investigator for the trial.
Potential volunteers of a vaccine trial need to undergo a series of screening, including a check for antibodies, before they can be enrolled for the programme.
Earlier this week, the ICMR, too, had come up with its sero-positivity report that found 57.2% children between the ages of 6 and 9 had antibodies against SARS-CoV2. For the paediatric population between 10 and 17 years, antibody prevalence was even higher at 61.6%.
“Earlier, we found antibodies in certain children who had come to the hospital with suspected MIS-C (multisystem inflammatory syndrome) or unresolved fever of unknown origin. On testing, they were found to have Covid-19 antibodies. So, we already had an inkling of a good number of children having antibodies. Now, the ICH data along with the ICMR survey report brings a ray of hope,” said ICH associate professor Prabhas Prasun Giri.
The fear about children being worst-hit during the possible third wave arose primarily because they are yet to be vaccinated though a section of health experts like IPGMER hepatology head Abhijit Chowdhury and neonatologist Arun Singh, national advisor with RBSK (Rashtra Bal Swasthya Karyakram), have been insisting that this apprehension has no scientific basis or evidence.
“Children have been equally exposed to the virus as adults. It is just that their immature immune system don’t mount the kind of resistance to the virus like that of adults. That is the reason despite being infected they mostly remain asymptomatic exhibiting no sign of the infection,” said Chowdhury.