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How Antibody Tests Can Inform Public Policies To Mitigate Coronavirus Pandemic

LULU GARCIA-NAVARRO, HOST:

The only way we'll truly get a hold of this pandemic and come out the other side is through science - ultimately with a vaccine, but in the meantime through testing. There are tests that determine if someone who is sick has COVID-19 by taking nasal swabs, but also important is something called antibody or serological tests. And one of the places that's doing that is Stanford University.

Joining us now is Dr. Jay Bhattacharya, professor of medicine at Stanford University, who is part of this study. Good morning.

JAY BHATTACHARYA: Good morning.

GARCIA-NAVARRO: I read about long lines of cars with people showing up to give blood samples for this surveillance study that you just conducted. In all, volunteers collected blood from, I think, around 3,000 people. What were you looking for?

BHATTACHARYA: Yeah. It was actually amazing the community response. The main thing we're aiming for is to find out what fraction of the population in Santa Clara County have had a history of exposure and infection with COVID-19. The tests that people use to identify active infection just checks to see if the virus is there. But once you've cleared it, which is true for most people, actually, they won't have the virus in them. What they will instead have is antibodies to the virus, and that's what we're looking for - antibodies to the virus that provides evidence that there was previous infection or - and sometimes also current infection.

GARCIA-NAVARRO: So how can this information be used?

BHATTACHARYA: So all of the models that project forward for what the epidemic is going to look like require an understanding of how many people have been infected - not just how many people have been infected and identified with an active infection, but the total number of people, including people who've recovered. If you don't know that, you don't know how far along the epidemic you are. You can't project forward. So it's really useful for that kind of purpose to project where the epidemic is actually headed.

The other thing it's really useful for is understanding the death rate. To date, most people that have been trying to calculate death rate have tried to guess how many people have been infected. We don't know how many people total have actually been infected.

GARCIA-NAVARRO: And that's because, of course, a lot of people are asymptomatic. So you could be walking around and feeling fine, and yet you are actually infected with the coronavirus.

BHATTACHARYA: Exactly. Exactly. It's - there's that. And there's also people who - you know, they have relatively mild illness. They think it's a cold, and they don't show up. We'll miss them unless you do a study like the one we're doing, where we can look for antibody evidence in the population.

GARCIA-NAVARRO: Practically speaking, one of the reasons that this is, of course, really interesting to governments in particular is because that - this may mean that if a person has already had the virus, those people could then go back to work or potentially back to school. So if you could test them and see if they had immunity, then maybe you could give them a pass to be able to reengage in their lives.

BHATTACHARYA: Yeah. People have been talking about those kinds of things. I think there's still an active debate about - in the scientific community about the extent of immunity you get from the antibodies. I believe there's some, but the - how long-lasting they are. There's also questions about, is it the right thing to do to have these as, like - you have to be antibody-positive before you can go to work. It seems like it would be a difficult thing to implement.

I don't think a policy that relies on testing positive for the antibody and allow you to go back to work is likely to be feasible, and it would also create incentives for people to try to go get infected. I'm not sure I favor such a policy. But I think the...

GARCIA-NAVARRO: Yeah, the idea of, like, COVID parties like chickenpox parties is terrifying.

BHATTACHARYA: That whole - that's - I think that's - I think that could happen.

GARCIA-NAVARRO: I'd like to talk about the death rate. You spoke about the fact that you believed the death rate might be much lower than what had been originally predicted. We have north of 500,000 confirmed cases in the United States, the most of any country in the world. We've now surpassed Italy in the number of deaths. What do you think these serological tests may show us about the death rate, and how can that help inform us here?

BHATTACHARYA: Yeah. I mean, I think what we're - the problem is there's no vaccine, right? So even if the death rate's 0.1% or lower, that still means a lot of people may die from it, and that's something we have to take very, very seriously.

We also - I think also have to take seriously the fact on the other side of that - is the economic shutdown will have consequences for health and mortality around the world. It's hard to overstress this. When the world is poorer, more people will die. There'll be shorter lives and unhealthier lives not just in the United States, but around the world.

The Great Recession produced, famously, a phenomenon of decreases in life expectancy in the United States for the first time since World War II. A very large-scale economic collapse - that produces bad health outcomes. That, I think, is firmly established fact.

How extensively those deaths are going to be, those loss of health is going to be and how far around the world - that's something I think is going to need some very, very careful attention and thinking because if we continue the shutdown for - you know, I've seen people argue that we should continue the shutdown until there's a vaccine. Say that lasts a year. Well, a year of global depression will have an enormous consequence on people around the world. I mean, there are poor countries where people are on the brink of starvation just in normal good times.

So I think trying to understand what the right policy is involves understanding the deaths on both sides of this. That's where I am. I want to understand those better so we can make better policy 'cause right now, all of the focus has been on the deaths on COVID. But once we understand that, I think we need to see what the actual trade-offs between the deaths on one side of the policy and the other side and then make an informed choice on the basis of that.

GARCIA-NAVARRO: That's Dr. Jay Bhattacharya, a professor with Stanford Health Policy.

Thank you very much.

BHATTACHARYA: Thank you. My pleasure, Lulu. Transcript provided by NPR, Copyright NPR.