One-fifth of Chennai infected with Covid-19 till mid-July: Survey – Times of India

Chennai News
CHENNAI: A little more than 1/5th or 21% of the city’s population has been infected with SARS-COV2 or Covid-19, a seroprevalence survey conducted by the National Institute of Epidemiology (NIE) for Greater Chennai Corporation has found. Around 80% of the population is still susceptible to the virus, warned the survey whose results were released on Tuesday.
The NIE in July collected blood samples from 12,405 people from 51 of the 200 most populated wards of the corporation. Of these, 2,673 had evidence of catching the infection — their blood showed the presence of Immunoglobulin-G (IgG) antibodies.

The corporation estimates that by mid-July, 17.66 lakh people among a population of 82.16 lakh would have been infected.
The survey, however, showed that seroprevalence ranged from 7% in Madhavaram zone to 44.2% in Tondiarpet. Even among wards, 50% of sampled residents at Korukkupet in North Chennai showed presence of antibodies, against 25% in Saligramam and 8% in Mugalivakkam.
Corporation commissioner G Prakash said the survey had helped the civic body scientifically refocus its health interventions. “In zones where seroprevalence is high, the number of cases is gradually decreasing. We can see that they are attaining stability,” he said, indicating that efforts would be intensified in zones where the seroprevalence was lower.
The seroprevalence data also shows that among those sampled, more women (24%) showed the presence of antibodies than men (19%).
The seroprevalence was as high as 65% among those with a history of respiratory symptoms. Among age groups, it was highest in the 10-19 age group and the 40-49 age group and only 16% among those aged above 60.
Prakash indicated that since this was done in July, many more could have obtained immunity since then and that the corporation would continue with more such surveys.
The survey has found that the ratio of actual infections (as seen in the seroprevalence) to that of the recorded cases was lower in comparison to that in some published studies. This indicated a high testing performance, the study said. Similarly, the infection to fatality ratio was comparable or lower to that in published studies.
The study has also indicated that there is a need to understand why seroprevalence varies widely across zones so that control measures can be improved.

Source: https://timesofindia.indiatimes.com/city/chennai/one-fifth-of-chennai-infected-with-covid-19-till-mid-july-survey/articleshow/77881551.cms