Although there has been a slight decline in the number of new cases in the last one week, the State’s average Test Positivity Rate (TPR) for the last seven days (May 10 to May 16) continues to remain as high as 31.16%.
What is worrisome is that the TPR in at least 14 districts is higher than the State average during the seven days prior to May 15.
At 41.26%, Ballari has the highest TPR followed by 35.69% in Uttara Kannada. Chamarajanagar, Hassan, Gadag, Mysuru, Tumakuru, Udupi, Dharwad, Kodagu, Bengaluru Urban, Bagalkot, Shivamogga, and Vijayapura have a TPR higher than the State average. TPR in the last seven days is the lowest in Chitradurga and Bidar at 9.28% and 9.67% respectively.
Giridhara R. Babu, member of the State’s COVID-19 Technical Advisory Committee (TAC), who is also the head of Lifecourse Epidemiology at the Indian Institute of Public Health in Bengaluru, said TPR will increase when the background prevalence is really high and the number of tests done are less.
“TPR is estimated using the formula comprising the number of positive cases in the numerator and the total number of tests done in the denominator. Test positivity will increase when the denominator is small or the numerator is high,” he explained.
‘It is disadvantageous to reduce the number of tests when you have a high prevalence in the community as the TPR will not come down. This is what is happening in Karnataka,” he said.
Dr. Babu asserted that the ideal thing to do during a surge in cases is to increase the number of tests to ensure that most infected people are detected and isolated. “This will help in containing the transmission and breaking the chain. However, by decreasing the number of tests we have reversed the gains that had been accrued in Karnataka where consistently a high number of tests were done throughout since the beginning of COVID-19 response,” the epidemiologist said.
V. Ravi, member of TAC, who is also the nodal officer for genomic sequencing of SARS-CoV-2 in Karnataka, said the TAC had never recommended less than 1.5 lakh tests a day. “At a stage during mid-April we also recommended that nearly 2 lakh tests should be done daily. But the tests have come down in the last fortnight, maybe due to logistical difficulties and an acute shortage of test kits. This is because there is a high demand from all States now during the surge,” he said.
Asserting that people will have to come forward for testing, he said: “Otherwise they have to isolate themselves if they have come in contact with an infected person. Lockdown helps in minimising contact, but people should also have social responsibility.”
Admitting that daily tests had reduced during the last fortnight, Jawaid Akhtar, Additional Chief Secretary (Health and Family Welfare), said this was mainly because movement of people had come down during the lockdown. Moreover, ICMR had also recommended syndromic approach and asked States to focus on targeted testing of symptomatic individuals, he said.
Following Chief Minister B.S. Yediyurappa’s directions to officials on Monday to carry out house-to-house surveillance, the number of tests conducted daily will again increase in the coming days, he said.
“Earlier, a lot of asymptomatic people were being tested. Also, many who wanted to travel were also getting tested but we have stopped that now. We have now decided to increase the use of Rapid Antigen Tests (RAT) by 30% and those who test negative on RAT will undergo RT-PCR tests,” the official added.
