Tondiarpet and Royapuram are the only zones in the Greater Chennai Corporation that have reported fewer cases per lakh population in the second wave of COVID-19 so far compared to the first wave, an analysis of zone-wise data showed.
These two zones in the northern region in Chennai were the worst-affected during the early phase of the first wave. A seroprevalence survey conducted by the National Institute of Epidemiology during the first wave in the second half of July last year showed that 44.2 % and 34.4 % of the surveyed population in Tondiarpet and Royapuram respectively had exposure to the SARS-CoV-2 virus.
According to the analysis, 2,424 people per lakh population tested positive for COVID-19 during the first wave in Royapuram. In contrast, 1,943 cases per lakh population have been reported so far during the second wave. These numbers were 2,341 during the first wave and 2,186 during the second wave for the Tondiarpet zone. (Refer to the accompanying infographic on the period and number of cases taken into consideration for the analysis).
In all other zones, reported cases per lakh population have significantly gone up already in the ongoing second wave.
Some of the zones where a sharp increase was observed were Perungudi, Alandur and Valasaravakkam in the southern region of the city and Ambattur in central region. For instance, the cases per lakh population went up from 1,888 to 3,633 in Perungudi.
During the second wave, the southern region of the city, comprising zone 11 (Valasaravakkam) to zone 15 (Sholinganallur), accounted for more cases compared to the first wave. While 26 % of cases came from here during the first wave, it was 31% in the second wave.
The central region, where nearly half of the city’s population resides, accounted for the maximum number of cases, both during the first wave (48 %) and the second wave (49 %). In contrast, the northern region accounted for 20% in the second wave compared to 26% in the first wave.
The zone-wise number of tests have not been made available by GCC to know if there were any disparities in testing that partially accounted for the variance in the reporting of cases.
P. Ganeshkumar, epidemiologist, National Institute of Epidemiology, Chennai, said that it may be misleading to read too much into the seroprevalence survey results and the possible correlation with the cases getting reported in different zones.
“What is more important is the fact that the majority of the population is still susceptible to the virus. Therefore, the way forward must be to vaccinate as much of the population as soon as possible,” he said.
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