With a huge spurt in the number of cases since the beginning of July, Karnataka’s cumulative COVID-19 Test Positivity Rate (TPR) has seen a huge jump from 5.56% to 8.61% in the last 14 days.
While this is marginally lower than the cumulative national average of 8.63%, at 16.21%, as on Wednesday morning, Karnataka’s daily TPR is much higher than the national average of 11.2%.
TPR, which is a vital marker in assessing the spread of an outbreak, is the percentage of people who are found to be infected by the virus from those who are being tested. While cumulative positivity rate takes into account all the people tested so far, the daily rate is for those tested on a particular day.
According to epidemiologists, a high positivity rate indicates that testing is relatively limited to people with high suspicion of COVID-19 and may miss new chains of transmission in the community. The World Health Organisation recommends that the daily positivity rate be below 5% for at least two weeks before relaxing public health measures.
As on Wednesday, the country’s highest positivity rate remained to be Maharashtra at 19.62%. This was followed by Puducherry at 17.72%, Bihar at 17.09%, Karnataka at 16.21%, and West Bengal at 14.51%.
The lowest positivity rate was recorded in Arunachal Pradesh at 1.80% followed by followed by Tripura at 3.16%. The third lowest positivity rate was recorded in Himachal Pradesh at 3.69 % followed by Sikkim at 3.74 % and Rajasthan at 4.15 %.
While Maharashtra, Puducherry and Bihar remained as the top three regions with high positivity rates, West Bengal moved down to the fifth spot as Karnataka climbed to the fourth spot in the last 24 hours.
Giridhar R. Babu, member of the State’s COVID-19 Technical Advisory Committee, said an increasing TPR indicates that the overall prevalence is on an upward trajectory. “It means the outbreak is expanding further and the State’s testing is not in pace with the spread,” he said. The need of the hour is to conduct periodical ILI and SARI surveys and test those identified, the doctor said, at least once in 10 days. “We have had only one such survey ever since the outbreak was recorded in the State in March. Now, especially when local transmission is happening, such surveys should be repeated once in 10 days,” he said.
He said isolating all those identified will help in cutting down the transmission level. “That is how Delhi did it and their TPR has dropped drastically and now stands at 5.72%,” Dr. Babu said.
Highlighting the need for increased testing, tracing and isolation of COVID-19 patients and their contacts, V. Ravi, senior professor and Head of Neurovirology at NIMHANS, who is part of the State’s COVID-19 expert committee, said it is important to keep positivity rate under 5%. “The State had managed to keep its TPR under 5% while the lockdown was in force. Once the lockdown was relaxed, cases surged and the rate of testing fell thereby increasing the TPR,” added Dr. Ravi.