With questions being raised on under-testing in India, Nivedita Gupta, senior scientist in charge of viral diseases at the Indian Council for Medical Research, speaks to Karishma Mehrotra about why the government has decided not to expand testing criteria beyond symptomatic travelers and contacts of those infected.
How many tests do we have, what is our testing capacity, and how will we track community transmission?
Our testing capacity is close to 6,000 tests per day. We have 1.5 lakh test kits and have ordered 1 million. Right now our inclusion criteria is only symptomatic travelers and symptomatic contacts of lab-confirmed infected. Today, we have revised it to include health workers too. In addition, for surveillance purposes, we are testing at each of our 51 testing sites, 10 samples per week of severe acute respiratory illness pneumonia patients as well as influenza-like illness patients who are not very sick. The inclusion criteria for testing remains the same but we want to be sure that we are not missing community transmission. If I detect any positives in any of these labs, I’ll step up the testing capacity for those particular areas where I am seeing community transmission. Then, it will be a completely different testing strategy where asymptomatic people get tested.
We have the capacity to do roughly 6,000 tests per day, but we are not testing people at that level and we have some of the lowest number of completed tests in the world. Why not do the random sampling that you are describing, as well as increase testing for anybody showing symptoms?
Till date, we have not documented community transmission. Why should we go on telling people who have no history of travel or any contact with an actual case (to get themselves tested)? If today, I am exposed to a suspect patient and I feel that this patient has Covid-19, and tomorrow I want to get myself tested because I am very scared. What is the flip side of this? The incubation period ranges from 2 to 14 days. If someone has a long incubation period, but tests negative, doesn’t that give a false sense of security to them when the test is meaningless? And then, if I tell people I cannot say if you are positive or negative, that person is going to want to get tested again and again. And, in this process, in a huge country like India, I’m not able to test people who genuinely may need testing because I’m wasting it on futile testing. Secondly, right now, we are stressing on home quarantine. But, if I test an individual who is asymptomatic or mildly symptomatic, and he is positive, then he would be requesting to be put in a hospital, saying to isolate me and you take care of me. Then what do I do? In a country like this, how many isolation beds, how many places does the government have for this? Though we are maintaining a stringent inventory, we need to make sure that we are not in a situation where I exhaust all my testing capacity in futile testing.
The better strategy that the government is following is that we have begun surveillance, as we did during the Zika virus outbreak in Jaipur. We did aggressive, house-to-house testing, even for asymptomatic individuals. That kind of aggressive containment strategy will be enforced wherever we see a community transmission. For the whole country, I cannot put in place those aggressive measures, because I have to be rational in a country like India.
Are there any other countries using this strategy?
China also did that as far as I am aware. If you look at the UK, they have been under-testing. US did not offer a free test, so obviously the accessibility of the test was poor and they have been under testing. Here, the government is offering testing free of cost. South Korea, on the other hand, has included all symptomatic individuals in their testing.
Explained: When to test and whom
Why not allow testing at private labs?
We have started dialogue with private labs. We are exploring CSR, and asking for free tests. They are still in the process of ordering the regents. They might be ready in a week or so.
What is the likelihood of community transmission?
If we slip on containment measures in any aspect, we will still have community transmission. From our surveillance mechanisms, we will pick up some amount of community transmission.
It could be a small cluster of community transmission which, I think, can be alleviated through aggressive containment strategies.
At what point can India say that we are over the hump?
Right now we are prepared for a long-term battle. Though we know rising temperatures will reduce the risk of transmission, every region in India has different climatic conditions. We do expect a dip, if we at all establish community transmision. But if we have widespread community transmission, then I think we will keep seeing upsurges. We are hoping that we are probably only seeing imported cases. Maybe with containment, quarantine and restriction of travel, these may go down.
What do you think about this theory that Indians have a stronger immunity because they are exposed to more viruses?
That is possible, but there is no scientific data yet to support this hypothesis. We also have been thinking about this. But we can’t claim unless we have substantial data-which we don’t-to validate those things.