It is time for Kerala to shift to the next stage of COVID-19 containment strategy.

The present strategy – isolating those coming from outside, testing them, tracing their contacts, quarantining them and testing and hospitalising the suspect cases among them – has had its benefits. It has largely succeeded in blocking the virus from freely radiating outwards to the community.

Now, the time has come to take our gaze away from airports and focus on the society. “We can no longer proceed under the impression that only those who had come from outside and their immediate contacts are infected,” said Dr B Ekbal, Kerala Planning Board member and the head of the expert group formed to advise the government on how to scientifically tackle COVID-19.

If there is community transmission, the existing strategy of focusing on just the foreign returnees and their primary contacts, and merely keeping others away from them, would be rendered largely useless.

If the virus has spread extensively, then it is time to aggressively identify the infected in the society and hospitalise them. South Korea had favoured such aggressive testing right from the start, and therefore did not go for complete lockdown.

Accumulating signs of community transmission

Dr Ekbal said it was still not known whether there is community transmission. But he said it was important to rule out the possibility.

There are indications that Kerala should take fears of community transmission seriously. Of the 286 affected, the source of infection of only 283 patients (200 Malayalis who had come from outside, seven foreigners, and 76 immediate contacts of those who had come from outside) is known.

Three cases remain a mystery – a health worker in Ernakulam, a labour leader in Idukki (who has now recovered) and Abdul Azeez of Pothencode who died on March 31. They have what health officials unofficially call 'bastard infection'; no one knows from where they got the seed of the infection. It is now feared that the virus-carriers who had infected these three patients were still out in the community, perhaps even unaware that they had been infected.

Doctors say certain people could be infected but because of their high immunity levels would come out of it quickly, even before they realise they have been struck. But such people can easily pass on the virus to others.

Then, there are the Tablighi Jamaat participants. Their chances of spreading the virus in the community is considered high. Already two Malayali men who had participated in the Tablighi Jamaat in Delhi's Nizamuddin area had tested positive.

Chief Minister Pinrayi Vijayan said all the 157 Malyalis who had returned from the Tablighi meeting had been identified and their immediate contacts traced. There were reports that 310 people from Kerala had taken part in the Tablighi Jamaat.

The contact tracing of Tablighi participants is a nightmarish prospect. At the most their close contacts – family members, relatives and friends – can be quarantined. But they would have returned to the state in packed trains or buses or planes.

At this stage, health officials say it is virtually impossible to scout for the people who had shared the same transport as the returning Tablighi participants. The names, dates and timings of the modes of transport have been given out. The best the health department can now do is wait, hoping that someone would make a frantic call.

It is also possible that many are going on with their lives, blissfully unaware that few days ago they had come into contact with an infected Tablighi participant.

Mass testing of high-risk groups

It is such a growing pile of scary possibilities that has pushed Kerala to take up rapid testing in a big way. Rapid tests can give results quickly, within an hour, unlike the PCR (polymerase chain reaction) tests that take at least two days to confirm the presence of Sars-CoV-2 virus, which is the cause of COVID-19 disease.

But rapid tests do not detect the virus, it looks only for the antibodies that are unleashed by the immune system to beat back the virus. If the PCR test is done on throat or buccal swabs, rapid test is done on blood, plasma or serum samples.

The plan, which would soon be submitted to the government, is to subject certain high-risk groups irrespective of whether they have symptoms or not to collective rapid testing.

Top on the list are doctors and other health workers who work in COVID care centres. Despite the precautions taken, two health workers have already been infected. There could also be some silent carriers, yet to show any symptoms.

If there is even a suspicion that a health worker is infected, an entire unit would have to be quarantined. If this happens frequently, and in COVID-19 hotspots like Kasaragod or Kannur, the strain on an already fragile health machinery would be unbearable.

COVID in disguise

Collective rapid tests will also be done in places where, in Dr Ekbal's words, “there is a clustering of respiratory or viral diseases”. Respiratory distress is a telltale sign of COVID-19.

“Many instances of viral pneumonia or fever are being reported in various parts of the state. They are not necessarily COVID-19 but we cannot leave it to chance at this stage,” Dr Ekbal said. So, people in areas around a public health centre or community health centre where there is a large cluster of respiratory or virus-related fever like dengue or H1N1 would also be subjected to rapid testing.

Urgent need for hospital beds

This will also mean mass hospitalisations. Kerala has already put in place a Plan C under which 122 hospitals (81 government-run and 41 in the private sector) would work together to make available 3,028 isolation beds and 218 ICU beds. If needed, more private hospitals will join the group.

Now, private hospital managements have informed the government that if hospital beds were not enough, bath-attached rooms in hotels and lodges around the hospitals could also be converted into isolation wards.

After rapid test, the confirmation

All who test positive in a rapid test need not be positive for COVID-19. The antibody the rapid test had detected could be for any virus, say dengue or H1N1 or Japanese Encephalitis. They are, at the most, potential Sars-CoV-2 carriers.

So the throat swabs of all who test positive in rapid tests will be subjected to the elaborate PCR tests to check specifically for the presence of Sars-CoV-2.

This would mean that Kerala would have to test the samples of 3500-4000 suspect cases every day, a dramatic scale up from the 450-500 tests Kerala does now. Dr Ekbal said Kerala at the moment had the capability to test up to 1500 samples a day. He said the capacity would soon be raised to 5000. The PCR tests are done in 10 centres in Kerala. To augment their testing capacity, 10 more PCR machines were purchased last week.

Pitfalls of rapid testing

Rapid tests can be a bit problematic as it can be way off the mark. “A negative result can mean nothing. It will take three to four days after the incubation period for the antibody to show up in the plasma. So if the test is done before that, which is likely in many cases, it can turn up a deceptively negative result,” Dr Ekbal said. This is why under the PCR tests, the samples are put under the PCR machine for a second time after two days.

Even a positive result could be misleading. “If the antibody detected is of the IgM type, then it means the person had recovered or is in a convalescent stage. Only if the antibody is of the IgG type, the person can be considered an active Sars-CoV-2 carrier,” Dr Ekbal said.

Search for Stage 3 infection has begun

Rapid tests are yet to begin in Kerala but search parties to spot community transmission are already active in Kerala.

The Indian Council of Medical Research, in association with Rajiv Gandhi Centre for Biotechnology, has identified 10 centres in each of the 14 districts where swabs of viral pneumonia patients are being taken for the more time-consuming PCR tests. None of these viral pneumonia patients being tested under this limited programme are not official COVID-19 patients.

So if any of them tests positive, it is a clear sign of community transmission.