An AIIMS study comparing COVID-19 sero-positivity rate between children and adults among around 4500 participants from four states has found comparable seroprevalence in the child and adult populations, leading the researchers to the conclusion that a third wave by prevailing variants is unlikely to disproportionately affect children.
The study has been conducted by a group of AIIMS researchers led by Dr. Puneet Mishra—from the Centre of Community Medicine as principal investigator. It has been based on midterm analysis of interim data from sero-epidemiological study among a population older than 2 years old with a proposed sample size of 10,000.
The 4509 samples were collected between March 15 and June 2021 from a Delhi urban resettlement colony, villages in Faridabad district under NCR, rural Bhubaneshwar, rural Gorakhpur and rural Agartala. The study found seroprsevalence of 55.7% in the 700 samples of those below 18 years of age, and of 63.5% in the 3809 above 18 years of age.
“SARS-CoV-2 sero-positivity rate among children was high and comparable to the adult population. Hence, it is unlikely that any future third wave by prevailing COVID-19 variant would disproportionately affect children two years or older,†states the conclusion of the study.
Among the children who were part of the study, 33 were between 2-4 years of age, 153 were between 5 and 9, and 512 were 10-17. Children in the 10-17 age bracket showed a sero-positivity rate of 60.3%, higher than that of the 2-4 and 5-9 brackets which showed 42.4$ and 43.8% respectively, which the study attributes to higher mobility and independence of the older children.
At the urban Delhi site—where the study found an over-all sero-positivity rate of 74.7%—it stated that the difference in sero-positivity rate was “obliteratedâ€.
“During the first wave of the pandemic in India, the worst affected areas were the large urban areas, including Delhi. We collected the data during the second fortnight of March 2021. This was the time when the first wave was subsiding and the second wave had not yet started. 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 obliteration of any difference in sero-positivity rate between children and adult suggests that as the disease become generalized, it affects all age groups equally,†it stated.
However, Dr. S.K. Kabra, head of Pediatric Pulmonology at AIIMS, cautioned against drawing major conclusions from the study.
“The main thing we can say from the study is that the proportion of children and adults with antibodies is equal. It has measured only total antibodies (which show that exposure has taken place) and not neutralizing antibodies (which defend against the virus). Also the number of children in the sample is small and a major issue is that it has used cluster sampling, where a family was a sample. That might lead to overestimation… Again in some areas, it was collected before the second surge, and there’s no data to say there was herd immunity where 70% sero-positivity was found. Lastly, the question of mutation is there,†he said.
