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Health & Science

As International Travel Resumes, Here's How Important COVID-19 Testing Will Be

SCOTT SIMON, HOST:

EU ambassadors recommended this week that their countries allow travelers from the U.S. without having to quarantine, so long as there's some kind of COVID passport and testing requirement. As for EU citizens who may be eager to visit the U.S....

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JEN PSAKI: We certainly understand the desire of many Europeans to come travel to the United States and vice versa.

SIMON: White House Press Secretary Jen Psaki.

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PSAKI: We can't respond to public pressure or even emotion. We have to rely on the guidance of our health and medical experts.

SIMON: Well, we have such an expert with us - Dr. Ezekiel Emanuel. He heads the Department of Medical Ethics and Health Policy at the University of Pennsylvania.

Thanks so much for being with us.

EZEKIEL EMANUEL: Good to be with you, Scott.

SIMON: More than 60% of U.S. adults have had at least one dose of a COVID vaccine. Is there a percentage you have in mind, a percentage of people who have been vaccinated, that would allow the United States and, for that matter, the European Union to begin to relax some of these requirements?

EMANUEL: First of all, allowing travel of vaccinated people and people who test negative is relaxing requirements with no quarantine, and we should celebrate that. That is a great achievement. As a matter of fact, I'm planning to go to Europe. But my own perception is that as you progress from about 40% of the population vaccinated on up, you get dropping cases, dropping deaths, dropping hospitalizations. And we don't know what the herd immunity or whatever threshold is that brings us down to sort of flu-like deaths. About a hundred to 150 deaths a day is, I think, the flu-like level we're aiming at or we should be aiming at. We don't know how much vaccination that's going to require, but it's probably somewhere around 70% of the population, 75% of the population. So that's the aim.

SIMON: Should travelers always be tested more or less anyway on the theory that vaccinations obviously might lose their efficacy as time goes by?

EMANUEL: Well, I'm not sure. The CDC does say that if you're vaccinated, you don't need to test before traveling, and you don't need to quarantine. If you're not vaccinated, you should have a test within 72 hours of the trip. That's their position. Switzerland requires both vaccination and a test within 72 hours.

SIMON: Are some tests better than others?

EMANUEL: Well, we have two kinds of tests, broadly speaking - the rapid antigen test and the PCR test. The virtue of the PCR test is it's not going to miss a case. The vice is that it's not going to miss a case. And sometimes, it picks up cases that aren't. In other words, it gives you false positive rankings, and that is its chief problem. On the other hand, the rapid antigen tests - they will miss some people who are positive. So they will give you what's called a false negative. They will say someone isn't infected, but they really are. They're just early on. And if you retest them in 24 hours or 48 hours, they will test positive. So people recommend with the rapid test to get several tests in a row. The advantage is they're rapid. They're cheap, and so doing several tests is easier.

SIMON: Sounds like you're not being deterred - you're going to travel this summer.

EMANUEL: Yes, I am going to travel this summer. I do think, is there some risk of my traveling? Yes, but I've been vaccinated. I will take a test within 72 hours of going. And frankly, we're going to a relatively isolated place and not going to dine inside and stay mostly away and, if we go indoors, still wear an N95 mask. And I will wear, by the way, an N95 mask on the airplane.

SIMON: Sorry to put you on the spot - do you wear a mask everywhere you go?

EMANUEL: No, I don't. Being vaccinated dramatically reduces your risk of getting COVID and getting a serious case of COVID, but it's not to zero. Some people who have been vaccinated have still died from COVID - 12 people out of 3.3 million people vaccinated in Los Angeles. Now, that's a very small number. That's one in 300,000. You compare that to car accidents where 30 people out of 300,000 die. So it's very small, but it doesn't reduce it to zero. And some minor safety precautions, like wearing a mask if you're going to be indoors for a period of time, I think, is still prudent.

SIMON: Dr. Ezekiel Emanuel, University of Pennsylvania, thanks so much for being with us.

EMANUEL: Great to be with you, Scott. Thank you very much. Transcript provided by NPR, Copyright NPR.