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Interview With ICMR Epidemiology Head: What To Make Of the New Testing Strategy?

Interview With ICMR Epidemiology Head: What To Make Of the New Testing Strategy?

A health worker collects a swab sample for a COVID-19 test at a government hospital in Kolkata, January 14, 2022. Photo: PTI

  • The Union health ministry modified its COVID-19 testing guidelines to say asymptomatic contacts of an infected person don’t have to get tested unless they’re vulnerable.
  • The implications of this are not straightforward, so The Wire Science spoke to ICMR epidemiology chief Samiran Panda to understand its nuances.
  • During the interview, Panda touched on this aspect as well as the need for sero-surveys, home isolation, free testing kits for the needy, the R0 number and others.

New Delhi: The Ministry of Health and Family Welfare recently modified its COVID-19 testing guidelines. The new guidelines, which Indian Council of Medical Research (ICMR) director general Balram Bhargava referred to in a recent press conference, say that asymptomatic contacts of a person confirmed to have a SARS-CoV-2 infection don’t have to get tested unless they are older than 60 years and/or are immunocompromised.

This sounds straightforward – but isn’t.

While a section of independent experts has supported the change, others have said it could have a far-reaching impact on the overall number of COVID-19 cases that the Indian government captures.

The Wire Science spoke to ICMR’s head of epidemiology, Samiran Panda, to understand the nuances. The questions are in bold. The answers have been presented in full, with light edits for clarity. The Wire Science’s additions and word-substitutions are in square brackets.

What is the rationale for the new guidelines?

A person with suspected symptoms of COVID should be cared for in isolation – at home or in a facility depending on the severity of symptoms. Home test, isolation, care and monitoring guidelines serve useful purposes in this regard.

Contacts in the family of this symptomatic person should also monitor their own health to identify appearance of symptoms at the earliest. All [persons], irrespective of symptoms, should use masks.

While most of the cases improve at home with supportive care and management, any worsening of symptoms should prompt consultation with a physician. It is also important to appreciate that as hospital-acquired infections of different kinds remain a distinct possibility, decisions related to hospital admission for a symptomatic individual are best assessed by the treating physician.

At-risk individuals in the family, such as the elderly and those with comorbidities, gain more by using tests with higher sensitivity, particularly in a situation with no symptoms.

What should be the appropriate strategy? We had COVID-19 in January 2020, January 2021 and in January 2022. Although the months are the same in these three successive years, that does not mean the epidemic was the same in all three. The change in force of infection, the epidemiology of the disease and the pace of vaccination have gone through considerable changes over this period.

Public health measures evolve based on these changes and should inform our testing, management guidelines, etc., which can’t remain static.

So what one needs to do is quarantine for seven days but without being tested. From the public health perspective, this may seem to be a sound strategy, but from an individual perspective, it may be difficult to take leave from work for a week without a report. And to quarantine each and every member of the family in a small house is not easy. So why do the guidelines ask people to lock themselves up without a test?

From an individual’s perspective, home-based monitoring of one’s own health remains useful. Guidelines in local languages, such as ICMR infographics, come handy in this regard.

On the other hand, if a workplace requirement necessitates one to furnish a RT-PCR result, that is a particular case in consideration. However, mask use remains the key irrespective of the type of test used and its result, as masks are important infection-prevention tools.

But I am asking about testing, specifically, and not isolation.

If you have a space constraint, using a mask even at home is useful. Secondly, if there is a space constraint, it can’t be expanded overnight. The decision to seek admission to a hospital should be guided by a treating physician and should be based on regular monitoring of body temperature and oxygen saturation.

A health worker collects swab sample of passengers for COVID-19 tests, at the KSR Railway Station, Bengaluru, January 16, 2022. Photo: Shailendra Bhojak/PTI

That’s why I am trying to understand: why not get a test and be sure that one is positive and then go quarantine – without doing it otherwise.

How will you quarantine at all [with or without a test] if a room is small? That is not going to change. If [an employer] requires an RT-PCR test as a criterion for giving leave, that’s a special case. If there is such a guideline for an employee, they must adhere to that and nobody prevents them from getting tested. But that should, in any case, not be an alternative to masking. A mask is a must.

There is also a wariness of missing out on cases and not knowing the true picture of the epidemic if not all asymptomatic individuals are going to be tested. What do you think?

Some of the individuals without symptoms will be not infected and some of them may harbour an infection. Now, epidemiologically, if you know for every symptomatic case how many asymptomatic cases you could expect, you can estimate the true burden of cases. You need not have a head count of all infected individuals.

We have seen such estimations happening during the past three national seroprevalence surveys.

They reveal the actual number of  infected individuals. We need not count cases like [the Census does with the] population. Epidemiologically, if you can develop a multiplier and use that, you can always get to know what the estimated number of infected individuals could be.

So we can know the true burden of cases in retrospect by conducting seroprevalence surveys. Is that what you mean?

No, we can do that even today. But if somebody is coming up with an estimated number [calculated using the multiplier], that is not going to serve any purpose at an individual level. If somebody is not symptomatic, it is going to remain so [i.e., not turn into a severe case], and if regular monitoring witnesses him or her to go through the phase of resolution, we should be happy about that.

[That is, if regular monitoring finds that the individual recovers this way, we should be happy.]
A COVID-19 patient at a COVID Care Centre at the Commonwealth Games village in New Delhi, January 16, 2022. Photo: Kamal Kishore/PTI Photo

We can use the same correction factor that previous seroprevalence surveys indicated for this wave to understand the true number of cases, and not stress on doing a head-count of cases. Right?

Yes. But you can even try to modify that multiplier [or correction factor] on the [basis of] the natural history of the omicron variant’s spread worldwide. Because we know in the case of the omicron variant that 80% of infected individuals

are asymptomatic and [around] 20% or so become mildly symptomatic.

Hasn’t that been true about the original strain of the virus also?

In the earlier stages of the epidemic, in previous years, a distinct proportion had the propensity to have severe disease and pose a burden to the healthcare system. With the omicron variant, such challenges are [fewer].

However, people with comorbidities, such as cancer, liver cirrhosis or uncontrolled diabetes, are presenting with advanced stages of SARS-CoV-2 infections at hospitals. That is why detecting infection early and monitoring remain critical in this population group.

Also read: Have You Tested Positive? Here’s Why You Shouldn’t Ask if It’s Omicron.

There is a concern about onward transmission – in the sense that if one doesn’t know that they are positive and they are asymptomatic, they will continue to spread the infection. Do you think quarantine will prevent this from happening, in any case, with or without a test?

Let’s assume there is continuous onward transmission simply because the omicron variant is highly transmissible. If the reproductive number ‘R0’ is 2, every infected person will, within two days’ time, [pass the] infection to two more individuals. Let’s say both these individuals are asymptomatic. They, in turn, will pass on the infection to four more people.

Out of these, three will probably be asymptomatic. The one who is symptomatic will follow home isolation guidelines and, if mildly symptomatic, become [all-right] in 4-5 days. Such understanding will help inform public health measures.

If we say, “Oh, what about those three people who were asymptomatic and happily mingled with their families” – the guideline says they should follow quarantine [protocol] and the monitoring guidelines. At the population level, it would be impossible to track asymptomatic individuals at the present stage of the epidemic.

See, nobody is talking about the flu [also a respiratory infection]. It also causes asymptomatic and symptomatic cases. People are recovering there, too. We are not bothered there.

Just for the sake of clarity, does the flu spread like the novel coronavirus? Can we compare the R-numbers for both viruses?

The R-number [i.e. R0] is not a constant number. It keeps changing. For measles, it was once said that its R-number was 20. The R-number is a time-variant factor that is influenced by the population density of an area, the travel contact matrix, followed by the mixing of population groups, etc.

Workers make face masks and PPE kits in a manufacturing unit in Ahmedabad, January 17, 2022. Photo: PTI

Many people in India are now increasingly using rapid antigen test (RAT) kits at home. If one tests positive, how does one upload the result onto a government website, so that it gets reflected in the country’s caseload data?

People are encouraged to upload their results following home-based tests. There is a QR code on the kit. Using the code, whatever website [loads], you upload the result there. It also leads to the health ministry website. There is a kit-related [section] there. If one goes there, that page will give more information on how to [upload the result]. People’s participation and non-participation will determine the completeness of such reporting, though.

Countries like the US and the UK are distributing free RAT kits to not miss out on cases. We are not doing that. Is it because our epidemiological needs are different or merely because the large population size is a constraint?

If you ask me about free tests, I go back to the past and can see that many public health measures – when distributed free of cost – did not perform well for various reasons in our country.

You have to attach a value to a product, even if it is a small value.

Also read: What Happens When a Balloon Becomes a Free Drug? The Sorry Story of Nirodh

So you mean to say free tests wouldn’t work in India?

Public health programmes from the past indicate so.

Still, not everybody can afford multiple tests, even if a RAT costs Rs 200 per test. How do we address that?

If somebody can’t afford having home tests, then one can always use existing test outlets and at the same time adhere to public health advisories. Home isolation comes handy for [them] as well.

Last question: Could you please say if the WHO or any country has advised or adopted a similar strategy, of not testing asymptomatic individuals?

Each country develops its own testing and treatment decision algorithm based on the evolving stage of the epidemic, and those drafts therefore [are] dynamic documents, and rightly so.

WHO advisories are also available, which speak of different strategies in different prevailing situations and around various considerations. There is no one-size-fits-all approach.

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