86 per cent Mumbaikars have Covid-19 antibodies: BMC

Passengers queue up for the Covid antigen test on Friday. Pic/Sayyed Sameer Abedi

The result of the fifth serosurvey has brought some relief to the civic body, as the cross-sectional study has shown Covid-19 antibodies among 86.64 per cent of the surveyed Mumbaikars. Seroprevalence was significantly higher in study subjects who received either first or both doses of vaccine as compared to their unvaccinated counterparts, said officials.

The study included participants, aged 18 years and above, from all 24 wards of the city and were selected by systematic random sampling and those visiting Municipal Dispensaries and General Practitioners' Clinics in slum and non-slum areas, respectively. Participants were recruited with informed consent. Data collection was done by the means of a mobile software application. Total samples collected and tested was 8,674.

"Results of the previous three serosurveys conducted by the BMC concluded that the recent trends in seropositivity corresponded with the Covid-19 cases in the second wave. The fifth serosurvey could be instrumental in identifying trends of probable upcoming third wave and exposure of the population to the virus," said a civic official.

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According to the survey, overall seroprevalence in the city is 86.64 per cent. Interestingly, the seroprevalence in both slum and non-slum areas in the city is much higher than the last serosurvey. In the fifth serosurvey, prevalence in slum population has been recorded at 87.02 per cent and non-slum population 86.22 per cent. There is marginal difference in the gender-wise seroprevalence, with antibodies present in 88.29 per cent surveyed women and 85.07 per cent men.

As the seroprevalence among the vaccinated individuals is much higher than the unvaccinated, it is essential to strengthen the ongoing Covid-19 vaccination program. Almost 65 per cent of the study subjects received Covid-19 vaccine and 35 per cent did not receive any vaccine. The seroprevalence among partially and fully vaccinated participants has been found at 90.26 per cent and among unvaccinated at 79.86 per cent. Out of the total samples tested, 20 per cent were of healthcare workers and 87.14 per cent of them have antibodies.

"Even if antibodies are found, precautions like use of masks, maintenance of hand hygiene and a safe physical distance must be followed. The BMC has conducted three Sero-Surveillance Studies for Covid-19 and one sero-surveillance study only for paediatric population previously. The third Covid-19 wave is anticipated," said a civic official.

8,674
No. of samples collected and tested for survey