ARI SHAPIRO, HOST:
When someone tests positive for the coronavirus, public health workers trace that person's contacts. Today that contact tracing effort is focused on President Trump. NPR's Selena Simmons-Duffin has reported a lot on contact tracing during this pandemic, and she's here to fill us in.
Hi, Selena.
SELENA SIMMONS-DUFFIN, BYLINE: Hi, Ari.
SHAPIRO: First, remind us how contact tracing generally works, and then what makes this case different when the president is at the center of it?
SIMMONS-DUFFIN: Well, across the country, there are tens of thousands of contact tracers at NPR's most recent count - 40,000. So normally, here's how it works. When somebody tests positive, they get a call to think back to everyone they had close contact with for two days prior to the positive test or symptoms. So then those contacts are told to quarantine in case they're infected as well.
The timing here - that two days prior to symptoms - has to do with the infectious period of coronavirus. We know that it can spread even when somebody doesn't show any symptoms. And it's not actually clear when the president's symptoms began. So we're not sure when public health workers who are working on this are starting their counter for when the president might have been infectious. But this is obviously not a normal case. And there are two big questions. How did the president get infected, and could he have infected others?
SHAPIRO: So to start with that first question, how did the president get infected? Can contact tracers figure that out?
SIMMONS-DUFFIN: Well, they'll certainly be trying. We know now that Hope Hicks, who's one of the president's closest aides, tested positive on Thursday, and that several people who were at an event with the president on Monday in the Rose Garden have also tested positive. At last count, I think it was five people. I talked to Crystal Watson about this. She's at the Johns Hopkins Center for Health Security and an expert on contact tracing.
CRYSTAL WATSON: We're seeing more and more evidence that there are additional cases here. And so we need to understand how big that outbreak is and whether other people should be worried beyond just those who had contact with the president and the first lady.
SIMMONS-DUFFIN: So more results are trickling out from the White House, mostly negative. The vice president tested negative, for instance. And I understand the tracing effort is being conducted in-house at the White House. The D.C. Department of Health told me it is not involved.
SHAPIRO: So to look at the other question, who the president might have exposed, you know, for many of us, we'd think about, oh, I went to the supermarket or the drugstore or the people I live with. The president was in four states and Washington, D.C., this week. He attended fundraisers and rallies and a presidential debate. Do all of the people at all of those events need to be considered a contact?
SIMMONS-DUFFIN: Well, public health officials in Ohio, Minnesota, New Jersey, they've all said that contact tracing is underway. And there are reports from Cleveland that 11 people involved in the pre-debate setup have tested positive. But here is a key point. Not all contacts are created equal. CDC defines a close contact as someone you were within 6 feet of for 10 minutes or longer, although it notes that mask wearing may affect the risk of spreading or contracting COVID. So thinking back on all of those events that you just mentioned, Crystal Watson says this...
WATSON: Ten or 15 minutes near the president, speaking with him, making direct contact without masks in particular - those are the people that are probably at most risk.
SIMMONS-DUFFIN: She also notes there's some evidence that coronavirus can be spread in the air. So people who attended events that were indoors with the president, like the debate, for instance, might be at higher risk.
SHAPIRO: And if someone at the debate like Joe Biden tests negative, does that mean that they're totally free and clear?
SIMMONS-DUFFIN: Well, not quite. The incubation period for the virus is about two to 14 days. So it could be that someone who was exposed and infected by the president or others in his circle are currently testing negative but are actually infected and could get sick later on. So the public health guidance here is that people who had close contact with the president or anyone who tested positive, for that matter, should contact their doctor or local health department for guidance about what their risk is and whether they should quarantine or get tested.
SHAPIRO: That is NPR's Selena Simmons-Duffin.
Thanks, Selena.
SIMMONS-DUFFIN: Thanks, Ari. Transcript provided by NPR, Copyright NPR.
NPR transcripts are created on a rush deadline by an NPR contractor. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of NPR’s programming is the audio record.
