Wells: I know what the world looks like right now with somewhat limited and sporadic testing, with test results that can take anywhere from a day to two weeks. What would the world look like if we were doing a million rapid tests a day with an uncertain number of false positives?
Madrigal: And an uncertain number of false negatives, like Jim was saying. Well, I think the mega-happy scenario would be that, in that big dragnet of screening, you would catch enough contagious people that you would start to really bring down the rate of transmission. One of the things that I’ve been thinking about from watching these numbers all the time is that, with our current set of strategies, we tend to do a pretty good job at bringing the rate of transmission down to, like, around 1.
Wells: And by “1,” you mean the average number of people that someone is passing it on to. Right now, each person on average passes it to one other person.
Madrigal: Exactly. And so, we can’t really get to truly suppressing the virus and back to normal life. But also, most places are not actually also seeing huge runaway outbreaks. And when places do a lot of the things that every public-health person says to do: mask, wash your hands, social distance, avoid large gatherings … all that stuff appears to get us down to around 1.
And so we’re kind of balanced on this knife edge where we’ve had a pretty hard time getting to suppression the way that Asian countries have. But we’re also not getting torched all the time. And so what I would hope testing would do, in the happy scenario, is be the thing that helps us start to drive way lower than one 1.
Wells: Would that look like: I wake up every morning and I test myself?
Madrigal: The way that it would start to roll out first—and the way that it almost certainly will with the Abbott test called BinaxNOW, their first very simple test—would be workplaces and schools. These are tests that could be done by a school nurse. It’s kind of unclear whether they’re going to be rolled out straight up for screening, like you’ll just go into the Ford plant and once a week you’ll do this test.
One of my sources said, “You know, we’ve been peddling testing strategies for months and without the ability to do lots of tests.” And no one cared. Now, suddenly, there’s this idea that maybe there’s going to be all these tests available. And now people are scrambling to put together strategies. The kind of strategy that strikes me as most likely is some kind of regular testing, and testing within groups that sort of makes sense to test together. These strategies, which have kind of been on the shelf, will get rapidly developed … primarily, I think, by companies, nursing homes that are already supposed to be doing some of this kind of testing, high-risk workplaces, emergency responders … If that starts to work and suddenly there’s tons of tests, in this happy scenario, you will take a test a lot. Like, more than once a week. In a lot of the modeling that people have done, you need to get to sub-weekly testing for everybody. That means billions of tests a month.