Mumbai: More than 50 per cent of Mumbai’s paediatric population has developed Covid antibodies, shows the result of a serosurvey conducted by the Brihanmumbai Municipal Corporation in April, May and June. The study, prompted by apprehensions that the anticipated third wave of Covid-19 was likely to impact the one-18 years age group, has revealed that 51.18 per cent of children in Mumbai have developed SARS-CoV-2 antibodies.
The results of the survey are a positive sign, as it means that the majority of the children have developed antibodies against the deadly virus, which are likely to last for the next three to four months. Meanwhile, the civic officials and doctors believe that this high sero-prevalence indicates possible herd immunity.
This survey was conducted between April 1 and June 15, in which 2,176 blood samples were collected from pathology laboratories, including 1,283 samples from the Aapli Chikitsa Network and the Nair Hospital of BMC, and 893 from a network of two private laboratories across 24 municipal wards. The survey, conducted by the civic-run BYL Nair Hospital and the Kasturba Molecular Diagnostic Laboratory (KMDL) also revealed that the proportion of the paediatric population having antibodies has increased, compared to the earlier sero-survey.
The key findings of this study suggest that more than 50 per cent of the children have already been exposed to SARS-COV-2. The overall seropositivity is 51.18 per cent, 54.36 per cent in samples collected from public laboratories and 47.03 per cent in samples collected from private laboratories. Seropositivity is the highest in the 10-14 years age group, at 58.31 per cent (public lab samples) and 46.81 per cent (private lab samples). The overall seropositivity rate in children aged 1 to 4 years is 51.04 per cent, while it is 47.33 per cent in those aged between 5 and 9 years, 53.43 per cent in those aged 10 to 14 years, and 51.39 per cent in those aged 15 to 18 years.
A sero-survey involves testing the blood serum of a group of people and the findings are used to monitor trends in prevalence. As the possible third wave of Covid-19 was anticipated to affect children disproportionately, the BMC had directed the serosurvey of the paediatric population during the second wave itself.
Dr Bakul Parikh, past president of the Indian Academy of Paediatrics (IAP) and part of the paediatric Covid taskforce. said there was no correlation between the data of the serosurvey conducted by the civic body and the speculation about the third wave, supposedly likely to impact children below 18 years of age. The serosurvey results are good, Dr Parikh feels, as it indicates a sign of herd immunity amongst the children, as most of them must have contracted the infection but gone unidentified, due to their being asymptomatic.
“It is a possible sign of herd immunity but it will be too early to comment that children will not be affected despite having higher seroprevalence. There is speculation aplenty of children likely to be infected as they are the ones now stepping out of their houses and interacting with people who might be carriers of the SARS-CoV-2 virus,” he said.
Dr Hemant Deshmukh, Dean, KEM Hospital said, “The survey result is great news, as it means that a majority of the city’s children have developed natural immunity against the virus, which will last for the next four to five months, providing them strong protection against the third wave.”
Additional Municipal Commissioner Suresh Kakani pointed out the notable increase in seropositivity in the paediatric population to SARS-CoV-2 in this study, as compared to the third sero survey that had been conducted in March 2021. “The March sero survey showed a 39.4 per cent seropositivity for the below-18 age group, which indicates that a significant proportion of children accessing healthcare services were exposed to the virus during the second wave. Significantly, the age group that reported highest seropositivity in samples received from public labs was the 10-14 years category,” he said.