Covid cases much higher: Experts
The discovery of a high proportion of people found positive in several states in the past two weeks after an increase in the Covid-19 tests is seen by the public health experts and virologists as a large number of uncounted infections now coming to light, defying the government's claims of low infections in India. They call for increasing further the testing of everybody to gauge the real state of the infections.
They say the high positivity rates show the epidemic has spread faster than the testing as deduced from the ramp up of the diagnostic capacity of screening the Coronavirus disease and the inclusion of all those with influenza-like illness symptoms in the testing criteria.
The average test positive rates — the proportion of people who test positive among those screened — over the past seven days are 22 per cent in Maharashtra, 12 per cent in Tamil Nadu, 11 per cent in Delhi, 9 per cent in Gujarat, 7 per cent in West Bengal, and less than 4 per cent in Kerala, Punjab and Rajasthan, among other states.
Experts say the relatively high positive rates in some states could be explained either through restricted testing earlier under which only the most likely suspects were screened for Covid-19 or through large epidemics under which a sizeable fraction of those tested are positive.
Health officials have pointed out that the country's diagnostic capacity for Covid19 screening has increased from less than 100 samples daily in early March to over 3,20,000 samples daily in July. But experts say the high positivity rates indicate the need for more tests.
"One measure of adequate testing is that we need to test 20 people to find one positive case — or a 5 per cent positive rate," said Shahid Jameel, a senior virologist and head of the Wellcome Trust-DBT India Alliance, an India-UK research partnership.
"In Delhi, we're getting one positive case after 10 tests, in Maharashtra, one after five tests. When the rise in testing is accompanied by a rise in cases detected, it means the more you test, the more cases you find," Jameel said.
"This means there are infections still to be detected. When increased testing is not accompanied by an increase in daily cases, it's an indication that the outbreak is under control."
Over 80 per cent of Covid-19 patients have only mild symptoms. "The absence of active and aggressive testing of all patients with ILI could facilitate the silent transmission of the virus," said Ooomen John, a public health specialist at The George Institute for Global Health, Delhi.
The Health Ministry said that actual caseload of COVID-19 in the country is 342,756. It said only 1.94 per cent of the cases are in ICUs, 0.35 per cent cases are on ventilators and 2.81 per cent cases are on oxygen beds.