How to understand if Kerala is doing enough tests: Interview with an expert

In an interview with TNM, Dr Mohammed Asheel, executive director of the Kerala Social Security Mission, explains the state’s testing approach and more.
Dr Asheel
Dr Asheel
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On Sunday, Kerala reported 61 new cases of COVID-19. This takes the total number of cases since the first incidence in January to 1,270. While the state has received a lot of appreciation for the way it handled the disease, there have also been questions on the testing strategy it followed. Is Kerala doing enough tests, it was asked, especially when numbers showed that other states like Maharashtra were doing a lot more testing in recent days.

Dr Mohammed Asheel, executive director of the Kerala Social Security Mission, answers questions about the testing strategy and the possibility of community spread in the state.

Q: How do we know Kerala is doing enough tests?

A: Two day ago, Chief Minister Pinarayi Vijayan spoke about the Test Positivity Rate (TPR) of Kerala being 1.7. This meant that for every 100 tests done, 1.7 persons are positive for coronavirus. World over, countries like South Korea which have managed to contain the disease spread, have been aiming to keep this number below 2. If this number increases, it shows that we are not doing enough tests.

The absolute number of tests – which is more in Maharashtra – does not consider the population size. Only when you consider the population size, can you understand the test adequacy. Ideally, if you want a TPR of 2 or less, the number of tests per million should at least be 50 times the number of cases per million.

As of Sunday, the tests per million in Kerala is 62.89 times the cases per million (the number of tests per million being 2,295.32, and the number of cases per million being 36.49). In Maharashtra, this number is only about 7.5, in Gujarat 12.3 and in Tamil Nadu 25. The national average is around 21.

Q: Can you talk about the different tests Kerala has been doing – from routine to augmented to sentinel surveillance?

A: What is most important is the approach Kerala has followed. Some people say it should be ‘test, test, test’. But it is like mixing paint in a bucket and throwing it in a well and then trying to scrape it all out. You cannot let all the people out without any quarantine and then do a lot of testing and hope to contain the disease. The strategy that Kerala has followed is: trace, quarantine, test, isolate, treat.

It is this approach that helped us flatten the curve earlier and bring the active cases down to 16 by the first week of May.

What we now see are the new cases coming from people who are returning to their home state from other countries and states. There is nothing we can do about that. What we can do is prevent local transmission of the disease from these new patients.

Our approach has been to put the asymptomatic people (coming from other places) in quarantine, and test those who show symptoms, put them in isolation and treat them. Then we find out the contacts of those who tested positive and put them in quarantine and so on. These cases contributed to the routine testing we do.

In addition, we began sentinel surveillance of health workers, newspaper delivery persons, vendors, social workers, media persons and others who are likely to have more social interactions. This used to be about a thousand tests a week but now we have increased it to 500 a day.

To save time, we began surveillance pool testing, where a number of samples are mixed together and tested. If it gave a negative result, we could rule out the disease in all these samples in one go. But if it tested positive, we will test each of the individual samples.

We also began augmented tests on the vulnerable category of elderly people, pregnant women and others. In 3,200 tests, only four have tested positive, and we could trace the source of infection for all four of them.

Q: The CM said that the number of deaths in the state is lesser this year compared to the same period last year. What does this mean?

A: That is excess death analysis, another step we did to ensure that there is no community spread. In Europe, excess death analysis gave a shocking number of 1,69,000. That means that many more people have died this year compared to the same period last year.

In Kerala, we have had lesser number of deaths. In 2019, for the same period, between the end of January and May, there were more than 93,000 deaths, while this year we have had about 73,000 deaths. That is 20,000 less.

One reason for the lesser number is the lockdown, which could have brought down the number of vehicles on the road, thus reducing road accidents. There is also another reason. We checked the deaths from other respiratory diseases in both the years. There were 81 pneumonia deaths in this period in 2019 while this year it is 53. So we have realised that the precautions we have taken against coronavirus – wearing masks, physical distancing and washing hands – have also worked to prevent the spread of other respiratory diseases such as pneumonia.

More importantly, it shows clearly that there is no community spread that has gone undetected. Because Kerala is a place where every death is invariably documented. Unlike for example Gujarat where the civil registration of death is only 88%, in Kerala it is 99.9%. So there is no chance that we would miss a COVID-19 death.

In Kerala, the Case Fatality Rate (CFR or percentage of people who die from the disease) for COVID-19 is 0.75.

Q: But in case there is community spread, how is Kerala prepared to handle it?

It is true that there are about 50 cases where the source of the infection is not yet known. The problem is there are many asymptomatic carriers of the disease. So these people – whose source is not traced – may not be able to tell if they had indeed come in contact with a coronavirus positive person.

Moreover, we call it community spread when there is a cluster of such cases in one place.

While all the data indicates that there is no community spread so far, it cannot be ruled out – it can occur at any time. That is the nature of any virus, and if there has been no community spread, there would not have been any diseases spreading across the world. So it is nothing unexpected.

In case it does occur, Kerala is prepared to handle it, with more intensive measures – contact tracing, geographical limiting, and so on.

Q: What are the benefits of reverse quarantine (sheltering those vulnerable to COVID-19 from the general population)?

A: The CFR in a healthy population is 1 to 2. However, in the elderly, this can go up to 36%. All the deaths reported in Kerala so far are of patients who had comorbidities. That has also been the pattern in 75% of the deaths in India. This is why reverse quarantine is important.

This does not just mean that the elderly person is quarantined in a room, but it is also important that they don’t come in contact with possible carriers of the disease. That’s why public vigil is needed and it is done by ward committee members and others.

Q: There have been cases of people violating quarantine. How can we ensure containment when more than 1.3 lakh people are in quarantine and there could be chances of violation?

A: It’s a small percentage of people who violate the quarantine (0.5%). In my opinion, home quarantine works better in Kerala than institutional quarantine. In the earlier phase, we followed only home quarantine and we were able to bring down the active cases to 16.

In home quarantine the person remains in one room, attended to by only one other person. But in the case of institutional quarantine, a person comes in contact with the doctor, the cleaning staff, the volunteer who brings food. All these people would also be visiting the other rooms in the institution. As well as their own homes. So if one person in an institution catches the infection, all these people would be at risk.

The difference between quarantine and isolation is – quarantine is for suspected exposure, that is for people suspected of having exposure to the disease, while isolation is for confirmed cases.

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