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Last Updated : Oct 01, 2020 09:34 PM IST | Source: Moneycontrol.com

45% population in Mumbai slums have developed COVID antibodies, BMC's second sero survey shows

A serological survey involves testing blood serum of individuals to check for the prevalence of antibodies against an infection.

The Brihanmumbai Municipal Corporation (BMC) on October 1 released its findings from the second sero-survey conducted by the civic body along with the Tata Institute of Fundamental Research (TIFR) and NITI Aayog.

BMC said that the findings from the second sero-survey are "similar" to the first round and that people living in slums have more antibodies than those living in buildings.

According to the civic body, over 45 percent of slum population and 18 percent of non-slum population in three civic wards had developed anti-bodies to COVID-19. This is in line with the BMC's findings during the first sero-survey, when it was estimated that over 57 percent of those living in slums and 16 percent living in non-slums have developed anti-bodies.


A serological survey involves testing blood serum of individuals to check for the prevalence of antibodies against an infection.

COVID-19 Vaccine

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"As a large cross-sectional survey in India, this study aimed to estimate sero-prevalence in the population based on random sampling methodology from the general population (slum and non-slum) and health care workers at two time points to infer epidemic spread," the civic body said in a release.

The second round, conducted in the R/North, M/West and F/North wards during the second half of August 2020, surveyed 5,840 target samples out of which 5,384 participants or 92 percent were recruited from the general population. A total of 728 health care workers were recruited for the study during both rounds.

"Sampling included people who may have been symptomatic and recovered or asymptomatic, without distinction and excluded those who were in institutionalized quarantine facilities," BMC said, adding that no sampling was done in active containment zones. Around 1-2 percent of the samples belonged to those who had participated in both the rounds, the civic body said.

The sero-prevelance among healthcare workers in both the rounds, according to the survey, was 27 percent in four categories, including health posts, dispensaries, health office and programme field staff.

"Although Sero-prevalence in women was marginally higher than men in both the rounds, age-wise prevalence was comparable in the first round in all the ages. However, in the second round, sero-prevalence in the age group above 40 was slightly higher," a BMC official said.

According to the civic body, the sero-positivity during the second round, coupled with the current number of cases being reported, "indicates there could be a reduction in the spread of infection in slum areas".

The civic body also noted that sero-prevalence observed among the health care workers working in slum areas was lower than in the slum population, and this could be due to "Corona appropriate behavior", including wearing masks and following hand hygiene.

The first round of sero-surveillance had started on June 3 and 6,936 samples out of an estimated 8,870 were collected from slum and non-slum population of the three civic wards in the first half of July. It showed a high proportion of asymptomatic COVID-19 infection in the city.
First Published on Oct 1, 2020 09:34 pm