80% COVID-19 patients asymptomatic, but no need to change testing protocol: ICMR

Responding to a question at the daily briefing, Dr R R Gangakhedkar, head of epidemiology and infectious diseases at the ICMR, said: “I have explained that 80 per cent people will have infection without symptoms. They will be asymptomatic but if you test them, there is a chance that they will be positive… We need to understand that the RT-PCR test comes positive after a person is symptomatic. People take time to be symptomatic. This means if I test him/ her when asymptomatic, the chances of him/ her testing positive are small.”

Stating that the test has “limitations”, he said: “This is a new disease, people are learning. We are intervening, taking quick steps based on our evolving understanding of the disease. As for testing strategy, your chances of testing positive become less as you near the infection time point. It comes positive when there are symptoms, so keeping in mind the cost effectiveness and risk-based approach, your yield will become less the sooner you test. Even to think about changing the testing strategy now… I cannot say.”

He said in hotspots, people with influenza-like illness are being tested. “How much we need to change the testing protocol, time will tell, based on the progression of the disease and the evolution of the tests,” he said.

Lav Agarwal, Joint Secretary in the Health Ministry, clarified that 80 per cent patients are “either asymptomatic or have very mild symptoms”. “Our testing criteria is detailed and takes into account asymptomatic high-risk contacts as well as people with severe acute respiratory illnesses,” he said.

He emphasised that it is always possible to make a clinical assessment of whether testing is required or not, based on the patient’s history.

With 1,540 fresh cases and 40 deaths being reported in the last 24 hours, the total tally has now gone up to 17,656 cases (2,842 recovered) and 559 deaths.

The average doubling time has increased to 7.5 days, from 3.4 days a week before the lockdown. The doubling time is more than the national average in some states and Union territories. Among these are: Delhi (8.5 days), Karnataka (9.2), Telangana (9.4), Andhra Pradesh (10.6), J&K (11.5), Punjab (13.1), Chhattisgarh (13.3), Tamil Nadu (14), Bihar (16.4), Andaman and Nicobar Islands (20.1), Haryana (21), Himachal Pradesh (24.5), Chandigarh (25.4), Assam (25.8), Uttarakhand (26.6) and Ladakh (26.6). Two states have a doubling time of more than 30 days: Odisha (39.8) and Kerala (72.2).

Three districts — Mahe (Puducherry), Kodagu (Karnataka) Pauri Garhwal (Uttarakhand) — have not reported any fresh case in the last 28 days. In the last 14 days, 59 districts, spread across 23 states and UTs, have not reported any fresh case. The six new districts in this list are: Dungarpur and Pali in Rajasthan, Jamnagar and Morbi in Gujarat, North Goa and Gomati in Tripura.

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