The Union health ministry has asked Bengal and some other states to ensure high Covid-19 testing counts, cautioning each against significant decline in average daily tests and worrying increases in positivity rates.

The health secretary, Rajesh Bhushan, while flagging state-specific decline in the daily testing rates, said it would be “very difficult to determine the true level of infection spread in a geography” in the absence of sustained levels of sufficient testing.

Bengal, for instance, reported 38,600 average daily tests during the week ending November 22, compared with 67,644 average daily tests during the week ending June 6 this year, Bhushan wrote in a note to Narayan Swaroop Nigam, principal secretary in Bengal’s health department.

“It is also worrying to note that the state has recorded a high (test) positivity of 2.1 per cent in the week ending November 22, having stagnated over the past four weeks,” Bhushan said. The positivity rate, the proportion of positives among those tested, is a measure of the size of the epidemic and needs to be as low as possible, and below 5 per cent.

Bhushan said several districts were reporting unacceptably high positivity rates combined with an increasing trend over the past four weeks. From November 15 to 21, positivity rates in Darjeeling, South Dinajpur, Howrah, North 24-Paraganas, South 24-Paraganas, Jalpaiguri and Calcutta had been greater than 2 per cent.
He has also expressed concern that the proportion of RT-PCR diagnostic tests — more reliable than the alternative antigen-based tests — accounted for less than 30 per cent of total tests in Alipurdar, Cooch Behar, Hooghly and West Medinipur.

“It is important that the state maintains high testing given the recent increase in travelling due to various events such as festive celebrations, marriages, and vacations,” Bhushan wrote. “A decrease in testing would undermine the infection spread within the community.”

The ministry also sent similar letters to Goa, Jammu and Kashmir, Kerala, Ladakh, Maharashtra, Manipur, Meghalaya, Mizoram, Nagaland, Punjab, Rajasthan, and Sikkim.
Bhushan’s letter to Kerala says the state conducted on average around 56,000 tests over the past week in contrast to over 296,000 daily tests during the week ending August 15.

He has also pointed out that test positivity rates in Wayanad, Kozhikode, Thiruvananthpuram, Kottayam, Idukki, Kollam and Kannur remained above 10 per cent combined with a decrease in testing over the past week.

In Goa, average daily tests during the week ending November 22 were 2,329, compared with 6,703 during the week ending May 9. Maharashtra reported 97,502 average daily tests last week compared with over 268,000 during the week ending May 23.

Health authorities have on average detected around 10,000 daily new cases over the past week from over 400,000 daily new cases in early May.
Sections of public health experts said a third nationwide wave was unlikely given India’s large proportion of population either already infected or vaccinated, but local outbreaks may continue to emerge whenever the virus got a chance to infect susceptible pools of people.