SARAH MCCAMMON, HOST:
This holiday weekend, it feels in many parts of the United States like the country has finally turned the corner on the pandemic. For many Americans, masks seem like a thing of the past and with good reason. The Centers for Disease Control and Prevention updated guidance in May to say that vaccinated people can resume pre-pandemic activities without a mask or worrying about social distancing.
But outside the U.S., the World Health Organization issued different guidance this week, urging everyone, even those who are vaccinated, to keep wearing masks because of the threat of the highly transmissible delta variant. That variant has now been detected in more than 80 countries and in all 50 U.S. states. In fact, the presence of the variant in California led the Los Angeles County Department of Health to strongly recommend that fully vaccinated residents resume wearing masks when indoors.
So we want to begin by exploring these conflicting recommendations. And for that, we've called Bill Hanage. He's an associate professor of epidemiology at Harvard's T. H. Chan School of Public Health, and he joins us now from Cambridge, Mass.
Professor Hanage, welcome.
BILL HANAGE: Thanks for having me on the show.
MCCAMMON: As we mentioned, the WHO and the CDC are providing conflicting mask recommendations. So why the discrepancy, do you think?
HANAGE: I think the difference comes down to the fact that the WHO is trying to give advice to the world, whereas the CDC is restricted to the United States. While the United States does have pretty good levels of vaccination pretty much everywhere - although there are some very worrying pockets, which I'm sure we'll come to - the world is nowhere near that. And so for the world, you want to be emphasizing those other things that people can do beyond vaccination, the social distancing in order to help control delta because delta really is bad news.
MCCAMMON: You mentioned those worrying pockets. Some public health officials and doctors believe that parts of the U.S. should have mask mandates but that it should be decided on a local or state basis, like the LA County decision, for example. What's your take on that?
HANAGE: I think that it's pretty reasonable because the fact is that it's kind of hard for someone to make a set of rules which are applying to, like, Cambridge, Mass., where I am - where the vaccination rates are really high and incidence is really low - and then also the same rules apply in a place where you have relatively high incidence and relatively low vaccination rates. Of course, it really is a very fine dance that people are trying to do here. It's very difficult to come up with something which is going to be a one-size-fits-all measure. And so pushing those decisions down to those levels seems actually like a pretty sensible thing to do right now.
MCCAMMON: It occurs to me that there's a challenge for public health officials - right? - that you want to avoid another spike. At the same time, there's a point at which you ask people to do too much, and they just won't cooperate. Is that fair?
HANAGE: Yeah, that's fair. And it's also true to say that just as public health officials have to say, hey, you've got to be really careful right now, take us seriously, there's also a point where you want to be able to say, OK, it's - we can be a little bit more relaxed now, but that isn't necessarily going to be the case everywhere.
I mean, take Los Angeles, which you mentioned earlier. Los Angeles has been putting in mask mandates, again. That's not only because delta's present but because there are at least two separate instances where delta has acquired an additional mutation, which we think may make it a little bit more transmissible. Don't know that yet, but it's the kind of thing that we need to be continuously watching and being very careful about when we put out guidance.
MCCAMMON: President Biden said yesterday that he wasn't worried about the delta variant causing another major nationwide outbreak of COVID-19. Is he right in his assessment, in your opinion?
HANAGE: I think that's right. I think that we vaccinated the nation enough that we're not going to get a sort of coherent nationwide spike like the sort we've seen before or to the extent that we've seen before. But I want to draw your attention to those pockets of the map where you have in some places about 30% of the over-65s unvaccinated. That's a number which makes me worried, frankly, because we know that delta's dangerous because it has been twice as likely to land the younger unvaccinated people in hospital because those are the only people who have been unvaccinated in the places where it's been studied.
We at the moment don't know how much more dangerous it could be in older people. And those are the places where, you know, we might find out something really pretty nasty.
MCCAMMON: I wonder if I can ask you another slightly personal question, which is, what are you doing these days when it comes to mask-wearing?
HANAGE: So for context, I live in Cambridge, Mass., where the daily rate of infection at the moment is really low. So when I leave the house, I carry a mask, but I don't put it on. I don't put it on when I'm outside. I don't put it on when I go into most stores unless there is a request on the door saying, please wear a mask. Where I would wear it would be if I was going into a very crowded space, poorly ventilated with loads of people whose vaccination status I didn't know much about. So it's context-dependent, but that's what I'm doing.
MCCAMMON: That's Bill Hanage, associate professor of epidemiology at Harvard's T.H. Chan School of Public Health. Professor Hanage, thanks so much for joining us.
HANAGE: Thanks for having me on the show. Transcript provided by NPR, Copyright NPR.