The lockdown on the Indian economy and the country is supposed to lift on May 3. Whether it will, and in what way and in how many cities and states, is not yet known. But most importantly, restarting the economy is not going to be easy or straightforward.

One of the key questions that has to be answered is: how many people can be tested in order to know how the disease is spreading, has spread, or is likely to spread. And that is a question that is obviously challenging not just those on the frontlines of medicine but also economists of many kinds in the country. One of them is Ajay Shah, professor at the National Institute For Public Finance and Policy, New Delhi, who recently wrote a blog on the kinds of testing that are available and the pathways India could follow as it restarts the economy to reduce the concerns that the larger populace might have about how this is going to go.

Edited excerpts:

There are two kinds of tests: the PCR test that looks for the virus in the body, and the antibody test that tests for the presence of antibodies that fight the virus in the body. The way they appear or can be tested happen at slightly different times. Which is best to understand how the disease is spreading or has spread already?

They are two different tests and they have interesting and different interpretations. The polymerase chain reaction (PCR) test says that the virus is present inside you right now, and of course this is extremely important in a clinical setting. If you were a doctor, and I were a patient, then you would very much want to know if this is COVID-19. You would want to know if it is present right now. And a great deal of the testing that has been done in India so far has been derived from this clinical setting--a person goes to the doctor, the doctor feels maybe there is something going on here, and asks for a PCR test for whether the virus is actually present.

A different line of attacking test is the so-called serological test which looks for antibodies. These show positive results at the end of the infection, so they are not very useful in a clinical setting but are actually extremely interesting from an information point of view, because it kind of says [whether] you have had the disease in the past. So we will identify people who may not have experienced any symptoms, may not have approached the doctor but who have finished with the disease, developed antibodies, and are likely to be immune to this disease.

These are the two different kinds of tests. And to complete the loop, we have to keep in mind that the PCR test is expensive and difficult to execute correctly--it requires proper storage of samples and so on. And the antibody test is easier to roll out. So these are two more factors that we have to keep in mind, when we think of these two kinds of tests.

What India is mostly using right now is the PCR test?

Yes, the bulk of the testing that has been done in India so far has been in the clinical context. Somebody went to a doctor and said I am not feeling good. And the doctor looking at the symptoms feels that this could be COVID 19 and recommends a test. And that is generally a PCR test. Important, but PCR test done in the clinical context is not a measure of what is going on in the country.

While policy-makers try to understand what it will take to restart an economy, what they would like to understand is how many people are likely to get affected, how is the disease spreading, where it is spreading. And you have some thoughts along that path…

The first is there is a conventional data set that tells how many people were tested--because some doctor recommended tests should be done--and have tested positive. That is category 1, data that is collected in a clinical setting.

I wish to argue that there are three other kinds of data sets that are extremely important and need to be created. Let us run through each of them

Imagine I am a public health official and I am nervous about one particular village, one particular neighbourhood, locality or housing complex. I am thinking that maybe there is an outbreak going on here. So I would like to have a measure about the neighbourhood. I am not interested in individuals, I want to know whether there is a problem in that particular neighbourhood. There is a very neat trick that can be done. You can pool the nasal swabs from roughly 10 people and do a pooled PCR test. The idea is you will only utilise one-tenth of the testing resource. You are only spending one PCR test for each ten people. So imagine that if there is one housing colony about which you feel uncomfortable, we could take a random sample of 50 people and do 10 pooled PCR tests. We will use only 5 test kits and we will get a measure about whether the disease is spread. We are not interested in identifying individuals but we would get a hang about what is going on in the neighbourhood.

So this is category 2. You want to test a neighbourhood. Let me give you an example: we will want to systematically test health care workers, employees at railway stations and airports, police personnel. For example, one would want to get a read out of what is going on at the Mumbai VT [CSMT train terminal] everyday. So everyday we should take a random sample of the employees at the terminal and do a pooled PCR test and we understand if there is COVID-19 in them or not? We are not interested in the individuals but in the VT [CSTM] station. This is category 2, wherein a public health official is interested in a question about the neighbourhood, takes a random sample and does a pooled PCR test.

Category 3 is an extremely important, very simple idea. Please go out into the population and take random samples of individuals and measure. So we should do the PCR test to know if individuals are presently infected and also do the antibody test to know whether an individual has had this in the past and are probably already immune. So I would want to see around 1,000 people in Mumbai who are randomly sampled, every week. So every week we should go take a random sample of Mumbai and that will give us guidance about the progress of the disease. And the conventional data just does not tell us what proportion of Mumbai is infected, has finished with the disease and so on. So we need the so-called panel data, where every week you take 1,000 people in Mumbai, in Delhi ...and test. This is the real data about the state of the infection and immunity in Mumbai, Goa, Delhi, Rajasthan...That is the category 3 test.

Category 4 testing strategy is just to go out with lots of antibody testing all over India, driven by an individual. So imagine I am an individual, I am a Swiggy delivery guy, maybe I am Swiggy Corporation and I am concerned with what is going on with my employees. Maybe I am an individual, I am feeling nervous and uncomfortable. I should have easy access to subsidised antibody testing, so that I get peace of mind. Look, all of us have a chance of encountering this; by the time we are done about 50-60% of India is going to be infected. And some professions and some people are more exposed than others. It is anxiety, it is concern, where am I? What is going on. And the antibody test is not very expensive. So I feel there should be large-scale access to a very [Bottom up] testing procedure. Look, if you feel nervous, there should be some subsidised way in which I can go get an antibody test. Different people will choose whether to get tested or not depending on their threat perception--have I been in a neighbourhood where there were other people who were sick, am I in a profession that has more frontline access, and so on.

So lots of people should be able to weave testing into their lives--if I feel nervous about the world, then I should test. It should be my individual agency, I should decide that I should want to get tested. So these are the four strategies of testing. One is clinical care testing; second is a public health official looking at an airport neighbourhood or railway station; third is systematic panel measurement; and fourth is bottom-up, individual-driven.

This has happened chronologically, already--India is already seeing the first, maybe there is a little bit of the second, and the third and fourth could come if India now goes into lifting of the lockdown, particularly on a sustained basis.

So we are going to need lots of energy all over the system, of many, many people thinking of how to build the institutional and organisational capacity. See, one of the problems here is that the large fraction of testing capacity in India is, frankly, in the private sector. The last time you or I got a test done, we got it done from a private lab. So we will need government contracting with private people, we will need many, many institutional and organisational arrangements to get these things done. And it is really a local government story, it should be done by the Mumbai municipality, by the Delhi government, by the Kerala government, the Kochi municipality...we need a lot of energy in the system applying to all these four strategies.

And what you are saying is if it becomes part of our lives, then the systemic responses, including the testing laboratories, the private laboratories--all will have the infrastructure at an affordable cost for all of us to go and get tested, by which time in any case a vaccine may be found…

We are all dreaming that there will be a day when a vaccine is found. But the thing is, today it is not here. And we all have to design a lifestyle for that world. And let us not think that COVID-19 is gone on the 3rd of May. The nationwide lockdown ends on the 3rd of May, but COVID-19 is here. And we all need to design a lifestyle where we are more careful, thoughtful and we are using better information, making better decisions. There are hundreds of decisions being made inside an organisation, inside a municipality, inside a healthcare facility and so on. So we should not think that there is one single decision based on one fact. And different data-sets that are required for different decision-makers in the country, to be more thoughtful and more analytical.

This is a medical crisis and challenge first, and then comes the economic crisis and challenge. We have talked about restarting the economy from a medical point of view and the testing point of view. Your thoughts on restarting the economy and the key challenges India faces and how it should be or could be responding in the months ahead?

I already alluded to it that we got to do much more at the local government-level--each place is different, so each district, each city should be looking at public health trade-offs. What can I sacrifice, what is essential to my livelihood? There are subtle trade-offs--do I want to go on with this activity or should I shut it off? We should not be thinking of blunt single rules that will apply for the whole country. India is vast and diverse. India is really a European Union, we are a giant 3.3 million sq km country. So, for example, in one district, people may think that the mandis are absolutely fundamental to the economy of the district. So we have got to get the mandis to work, and now let us figure out how to achieve greater hygiene in the working of the mandi.

There may be another district that says that mandis are not an important part of our life; our main livelihood, our business activities are different, so we should give up on the mandis, close them for six months and go to something else. So these are local trade-offs. So some businesses, some areas of activities are rescuable using better hygiene and social distancing procedures. Some things are not. These decisions are local and involve local negotiations.

Some things you can say flatly for the whole country. I think we are pretty certain that there should be no [opening of] places of worship, no weddings; there are some things we understand all over India. But the complexity of reopening the economy is about local questions, local conversations, local trade-offs, and local discussions. Now, on top of that, in my opinion what we are going to see all over India is a chequerboard pattern of different disease episodes and events happening in different parts of the country. Once again there is a need for local data, local thinking, and local response. Maybe my district will see an incipient flare-up. I will need good data about my district. So all the four strategies of testing need to be there. Then a municipal commissioner, district collector, local political leadership of the district of all parties need to come together and look at the data and think: do we need to go into a more extreme lockdown now because we are at the beginning of a disease surge?

Think of it like a cyclone warning. A cyclone warning has come and the local government looks at the satellite imagery, looks at the path of the cyclone and decides, “Hey guys, we need to shut it down and do A,B,C,D.”

So think of a chequerboard map all over India, where there will be different stories of this disease and we need the local government to lead the way on the kind of social distancing procedures. Imagine there is a kind of red, blue, green manual in Kolhapur district, in Parbhani district saying that based on local conditions, local trade-offs on our livelihood, our activities, we will have a red manual, blue manual and a green manual. Then the local leadership will look at the data on an ongoing basis and keep making decisions all through the year. I think that is the way we should think about reopening the economy.

I should also say that my friends in the private sector are often asking me when will this end? Are we there yet? Are we finished with this? And the story I want to always tell them is: During the Second World War, there were German bombers going over London. And there is this irresistible imagery of people wearing a business suit, carrying a briefcase, walking on the street, going to work while the bombers are going overhead and the bombs are going off. And I think that is the worldview we have got to bring for two or three years. We are in a horrible world and we have all got to muster the endurance and courage to carry on. It is going to be hard and brutal but we are all in this together and we have all got to find our way through. There is no easy ending unless you get a vaccine and you immunise the entire 1.3 billion people of India. But it is going to be hard. Look at how many years it took to do polio vaccination. So let us not think this is ending soon; it is a slow, long battle.

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