Amid a deadly second wave in India, with Maharashtra registering record COVID-19 cases, a survey done by the Brihanmumbai Municipal Corporation says that sero positivity is increasing in non-slum areas in Mumbai and it is decreasing in the slum pockets of the city. 

In Mumbai, a large number of people in non-slum areas are testing positive for coronavirus infection as cases are peaking. 

The BMC’s sero survey also showed that women have more antibodies than men to fight the COVID infection. The survey, released on Saturday, says, there was 37.12% sero positivity among women as against 35.02% in men.

Sero positivity entails a blood test showing a positive result for a particular antibody, officials said.

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“In the survey, 41.61% sero positivity was found in the blood samples taken from municipal dispensaries in slum areas. Overall, 36.30% sero positivity was found in 10,197 blood samples collected from citizens from all 24 wards in Mumbai,” said the survey.

The first sero survey, conducted last year in July, had shown 57% sero positivity in slum areas of three wards. The second sero survey, done in August 2020, showed 45% sero positivity in slum areas, an official said. 

“The blood samples taken from private laboratories in non-slum areas showed sero positivity of 28.% in the current survey. In the first survey conducted in July last year, this figure was 16% for three wards and 18% in the survey held in August,” he said.

The latest sero survey, held in March this year, was carried out using the “unlinked anonymous sampling method” with blood samples collected from those who had not been vaccinated.