In defence of ‘dynamic’ testing strategy for State

Kerala has adopted a ‘dynamic’ testing strategy for COVID-19, contrary to opinions aired by a few experts, Rajan Khobragade, Health Secretary, has said.

Most countries aim at a test positivity rate (TPR) of less than 2%, like South Korea. For Kerala, it is 1.5% against the national average of 4.3%. Since the TPR of Kerala is less than 2, doing more tests would be a wastage of resources. High case fatality rate and test positivity rate are indicative of testing the sickest and not doing enough screening tests. The State’s TPR of 1.5% and case fatality rate of 0.5% are indicative of better use of resources based on a dynamic testing matrix supported by contact tracing and quarantine activities, as per a publication on the State’s testing strategy by the Health Department.

Healthy figures

While the presumption is that the number of cases increase with the numbers of tests, it has not happened in the State, says Dr. Khobragade. On an average, Kerala has tested 71 samples for one positive case while at the national level the average is 23 samples for a positive case.

The State has also tried to capture indicators of community transmission by looking at the number of pneumonia deaths or a surge in hospital admissions with severe respiratory illness. However, no increase has been reported.

“The number of tests and the category of people to be tested have been expanded. Around 3,500 to 4,000 tests are done a day now,” says Dr. Khobragade. Depending on the situation in the days ahead, the testing strategy too would evolve.

The State would start another major surveillance testing as well. With the influx of Keralites from abroad and other States, the testing strategy has been revised to include more samples of people from localities with more COVID-19 positive cases or their contacts, he says.

The earlier strategy was to test symptomatic persons arriving at airports and seaports, while the asymptomatic ones were advised to follow strict home quarantine.

Targeted testing was done when testing facilities were fewer. Primary and secondary contacts were placed in quarantine and only symptomatic persons from these contacts were tested. This ensured judicious use of testing kits, while preventing transmission of the disease, as per a publication on the testing strategy.Dr. Khobragade says conducting more tests to identify more cases does not seem the right strategy as the State has from the beginning followed a strong quarantine strategy supported by a decentralised public health system. Sentinel surveillance has been adopted to detect community transmission. This began in the third week of April with a to test 1,000 samples a week.