Of 3,128 samples collected from amongst select groups in the community as part of an augmented testing drive on April 26, only four positive cases are found so far and 3,089 samples are negative. An official bulletin says that 14 samples are being reconfirmed and that another 21 samples rejected by the labs are being retested.
Health experts hail the move saying the community sampling being done in the State is a good attempt to find asymptomatic COVID-19 cases. The fact that the current lockdown would have kept such cases mostly within a closed circle may help in contact tracing and quarantining, if necessary.
Increasing the number of samples is likely to throw in more cases. The antibody testing, which has more sensitivity, could help pick up more cases than the RT-PCR (real-time polymerase chain reaction), says A. Fathahudeen, pulmonologist and critical care expert, Government Medical College, Ernakulam.
Asymptomatic cases
Sampling for identifying asymptomatic cases in the community is important as the State is on the path to lift the lockdown in a phased manner. So far only symptomatic cases and their primary and secondary contacts who developed symptoms are being tested. However, it is said that over 60% of the patients in the State are reportedly asymptomatic, says a medical officer.
“When you test more, you will end up picking up more positive cases and for policymakers this would create a kind of unrest for fear of bad statistics,” says Dr. Fathahudeen.
“The lessons from South Korea and Singapore teach us that testing is the only way to get out of the current lockdown mode and to continue with life and reduce the huge economic fallout,” adds Dr. Fathahudeen.
Sometimes a swab sample may return negative while another swab sample may be positive. Besides, the viral load in the secretions in the throat or nasal swabs could vary from time to time. In the asymptomatic person, the virus could be in fragments, sometimes only a skeleton or some bits, but the tests would show the presence of the virus. The nature of the virus present in an asymptomatic person could be ascertained only if a culture is made, but such facilities need high security precautions, says another medical officer. Hence, till the RT-PCR turns negative twice, the patient is not discharged.
No real studies
Dr. Fathahudeen says no real studies have happened, especially in the Indian context, to make a scientific statement on the viral load of asymptomatic patients.
As the State prepares to bring back people stranded in the Gulf countries, quarantine becomes most important in checking asymptomatic spread. It is not yet decided if all the people would be tested or only the high-risk ones.
