Coronavirus: Sero survey shows one-fifth of Chennai’s population exposed to COVID-19

The study was conducted after samples from 12,045 people across 51 wards were collected and tested for Coronavirus antibodies.

A recent sero survey conducted in Tamil Nadu’s Chennai showed one-fifth population of the city had been exposed to the novel Coronavirus. The sero survey was conducted by the National Institute of Epidemiology and checked the current status of COVID-19 transmission in the Greater Chennai Corporation (GCC) region. According to a report by The Indian Express, the study was conducted after samples from 12,045 people across 51 wards were collected and tested for Coronavirus antibodies. Among the tested people, 173 cases were found to have a contact history with a COVID-19 positive patient. It is to note that the field data for this study was collected between July 18 and July 28 and the corporation found a positivity rate of 10 per cent.

The report citing the study highlighted that around 80 per cent of the population is susceptible to getting the infection in Chennai and there is a need for control measures after studying the reasons pertaining to the prevalence of seroprevalence across zones. The study defined seroprevalence as the percentage of people having antibodies against SARS-Cov-2. It added that after the survey, a huge variation in seroprevalence across zones can be noted ranging between 7.1 per cent in Madhavaram and 44.2 per cent in Tondiarpet. Among the surveyed candidates, 6,493 females were tested where 1,538 turned positive. On the other hand, 5,785 male samples were taken in account where 1,115 were found positive.

It was shown that the female group had a higher seroprevalence at 23.7 per cent when compared to the male group at 19.3 per cent. The report asserted that 21.5 per cent of Chennai’s population has already reached the immunity levels by the time July ended. With the increased immunity levels, it is likely that the transmission rate will comparatively remain on a lower side going forward. Moreover, it is safe to assume that since July, the immunity level has increased in the last one month. Further, people above the age of 60 showed less seroprevalence (15.9 per cent) as against other age groups which had a seroprevalence of around 23 per cent.

Meanwhile in Tamil Nadu, more than 4.28 lakh cases have so far been recorded where around 1.35 lakh cases are in Chennai only. Around 7,000 people, unfortunately, succumbed to the infectious disease in the state. Tamil Nadu is also one of the five states in India having maximum number of new COVID-19 cases on a daily basis.