On May 8, deep into the second COVID-19 wave and more than a fortnight after Kerala first reported 20,000 cases a day, Chief Minister Pinarayi Vijayan declared lockdown. That day, there were 41,971 fresh cases and a test positivity rate (positive cases among 100 tested) of 28.88 per cent.
Four days later, on May 12, daily cases touched 43,529. And the TPR was nearly 30 per cent (29.75 percent). As it turned out, May 12 was the worst day of the second wave, both daily cases and the TPR recorded its peak.
In other words, the second wave that officially began from April 10, when the TPR got back to double figures (10 per cent) after 65 days of remaining in single digits, touched its peak on May 12. From then on, there was a decline, a drop that was also an advertisement for the lockdown.
The fall was swift but only up to a point. On May 26, 18 days after the lockdown, the TPR went below 20 per cent (19.95 per cent) for the first time during the second wave. In the next 22 days, there was a near 10 per cent decline. On June 17, the TPR fell below 11 percent, 10.85 per cent; the first time such a low was witnessed in the second wave.
What looked like a relief-inducing fall hit a level that was still uncomfortably high and then refused to drop any further. It was as if the villain had somehow got hold of some projecting ledge as he went hurtling down in a free fall. The TPR has remained in this relatively low but still dangerous 10-11 percent range ever since. This persistence of the virus in Kerala has delayed a further opening up of the economy.
Kerala: Delta's fertile ground
Even Kerala's COVID-19 warriors are mystified by the COVID's tenacity. Rajeev Sadanandan, the former health secretary and the government's chief advisor on COVID-19 prevention, said he could only speculate on what was happening.
“I suppose there are countervailing forces at work here,” he said. “On the one hand, there is the forward march of the highly transmissive Delta variant and on the opposite side, blocking the surge, are Kerala's vaccination drive and the TPR-based containment measures,” he added.
The Delta variant, considered far more infectious than the Alpha variant that had struck during the first wave, has enough space to go on a rampage in Kerala. The Sero Surveillance study conducted in January this year had found that only 10.7 per cent of the Kerala population had been infected by the virus and had developed antibodies.
This was a triumph of Kerala's containment, it kept fatalities low. But for the quickly evolving virus this was opportunity: Kerala as this huge untapped territory. “Now in July, more people than in January would have definitely developed antibodies, either through vaccination or infection, but still Kerala has more virgin population than any other state in India for the virus to hook its fangs on,” Sadanandan said.
Unlocking virus's potential
In fact, the virus has got more elbow room since June 16, the day Kerala began gradually easing its restrictions after a 40-day strict lockdown.
Incidentally, the TPR got stuck in the 10-11 per cent range after the unlock began. “People are back in the open and small gatherings are found everywhere, in front of shops and banks. All indicators point to a massive spurt in infections, which fortunately has not happened,” Sadanandan said.
Standing in the way of Delta's fierce onward surge are two factors. One, Kerala's vaccination drive; 32 per cent of Kerala's population has already taken at least a single dose of vaccine prompting the chief minister to declare on July 10 that Kerala is nearing herd immunity. Two, the TPR-based containment strategy where restrictions are graded on the basis of positivity.
Sadanandan said the TPR-based containment works not because of the forced restrictions. “Authorities might claim so but notifications of high TPR has induced behavioural change in residents of the affected areas. The knowledge of a high TPR, and what it means for their health, works as a bigger deterrent against going outside and mingling with others than the fear of the police,” he said.
Viral equilibrium
The vaccination and the containment measures have combined, in spite of the gradual social relaxations, to keep the virus surge in check creating a kind of equilibrium that Sadanandan says has kept Kerala safe. “The new cases are far below our hospital capacity and there is no shortage of beds or ICUs,” he said.
Till July 11, only 64.3 per cent COVID-19 beds have been used up in both private and government hospitals. As many as 56 per cent of ICU beds are still vacant, and over 60 per cent of ventilators are still left unused. As for oxygen beds, nearly 50 per cent are vacant.
It helped that the Delta variant, though hyper infectious, is mild. “Most cases are asymptomatic and require just home quarantine,” said Dr Chandni Radhkrishnan, head of Emergency Medicine at Kozhikode Medical College. “As a result, our hospitals were never overwhelmed during the second wave,” she added.
Ignore TPR, relax
This is why Dr K P Aravindan, one of the members of Kerala's COVID-19 expert committee, feels it would be self-defeating to read too much into the relatively high TPR. “Kerala is not doing random tests. We are testing the highly vulnerable and, therefore, the TPR will remain high for some time,” Dr Aravindan said.
Further, given the virility of the Delta variant, he said that during the second wave many were getting re-infected. The vaccinated are also getting the infection. "The point to be noted is, most of these people have mild or no symptoms. These multiple and breakthrough infections are getting reflected in the TPR, keeping it high. But it clearly is not something we should be worried about," he said.
The restricted opening of shops and banks as part of TPR-based containment was also causing problems. “When a shop in their area is closed, people move to a shop in an area where the TPR is low. This causes larger crowds in a lower TPR area triggering a fresh spread there. Same is the case with banks. Since banks open only on alternate days, the crowds that result are larger than what would have formed had they opened daily,” Dr Aravindan said.
So, according to him, it is high time the government stopped depending on the TPR to guide its COVID-19 strategy. “While taking a call on extending restrictions, we should be looking at other parameters like hospitalisations and severity of the disease. If both of these parameters are on the safe side, which is the case now, the restrictions should be further eased,” he said.
