Wells: On the vaccine, Jim, you mentioned that it may only be 50 percent or 70 percent effective. Can you explain what that means?
Hamblin: No vaccine is perfect, just like no medicine is perfect. No test is perfect. At best, a vaccine offers you a really good shot that if someone coughs in your face while they’re infectious, that you’re going to be protected. But our best vaccines are not 100 percent. There will always be some people who don’t mount an effective immune response or whose immune response fades. There’s been discussion about what the effectiveness of these vaccines against this coronavirus will end up being, and how effective they would need to be to even be worthwhile.
We don’t know yet. We’re waiting on these clinical trials. It’s very possible, even likely, that that effectiveness will end up being between 50 and 75 percent, meaning that you’re very likely to be protected if you have it, but you would probably still want to avoid really high-risk scenarios. Once you get a whole population that’s vaccinated at that level, it’s effectively gone. But when you’re just rolling it out to start with, it doesn’t mean that you go back to doing things exactly like you used to. It would be miraculous in terms of the number of cases dropping, number of fatalities dropping, but as long as there’s still that possibility, it means life does not go back totally to normal.
Wells: Right. Okay, let’s talk about testing. What are the realistic prospects of mass availability of cheap, rapid, at-home antigen testing? Is this the kind of thing where, in December, I’ll be able to go into a drugstore, buy a box of paper-strip antigen tests, and test myself every day? Is that going to happen, or are we really far away from that?
Madrigal: I think there will be something available, maybe not in December. But later in the winter and into the spring, I think there’ll be such tests available. One hope might be that the antigen test can soak up some of the less vital demand for tests so that PCR tests can be targeted at people who did have a high-risk exposure or who have presented with symptoms.
And other technologies are coming along. For schools in particular, pooled testing, where you take a bunch of different samples and run them through the same machine in one test. This technology is kind of, like, coming along and has some features that are quite nice for workplaces and schools—places where you know the group, you can assign risk factors to them, and you know you’re going to have continued interaction. This goes back to my main theme, which is: You have all of these things coming online that could help in some way, and when you layer them all on top of each other, does that get you somewhere?
That really is the question for me. I don’t think there’s any way that all those things are going to knock the virus out. But does it get you to what we’ve been doing so far: bumping along with a rate of transmission about one, which means each person that gets infected basically infects one other person? You don’t get runaway growth of transmission, but you also don’t really suppress the thing, and you continue to have community transmission out there. We’ve just been balanced on this knife edge of Rt=1. And over the winter, are we going to see that go way up or are we going to see it go way down? Or are we going to be able to stay balanced on this knife edge even as winter comes because we have this set of tools that help us stay close to that number?