Vice President Mike Pence and his wife Karen tested negative for Covid-19 on Friday morning, following the news that President Donald Trump and First Lady Melania Trump tested positive for the virus. Democratic presidential nominee Joe Biden also announced he’d tested negative on Friday. But a negative test result doesn’t necessarily mean that Pence, or Biden, or any top White House officials who have had recent contact with the President, are in the clear.
The Centers for Disease Control and Prevention recommends that anyone who has close contact with an infected person—meaning within 6 feet for more than 15 minutes—should quarantine for 14 days. That’s because depending on the person, it may take up to two weeks from first exposure for someone to start feeling sick, which is known as the incubation period. Additionally, it can take as long as a week from initial exposure to get a positive result on a Covid-19 test.
“People will have different incubation periods, probably related to the amount of virus they got exposed to,” says Dr. Mark Kortepeter, an infectious disease expert who formerly worked at the U.S. Army’s “hot zone” research lab. For example, you would have more virus exposure if an infected person coughs in your face than if they cough on the other side of a room.
“Testing someone a day or two after an exposure has extremely limited value.”
One of the challenges in responding to the coronavirus pandemic is the issue of “asymptomatic spread,” because people who are infected can be contagious before they even show any symptoms. This is one reason why the CDC and other public health bodies advise people to quarantine if they may have been exposed to the virus, and to isolate themselves if, like President Trump, they test positive.
It usually takes around 4-5 days for someone to show Covid-19 symptoms after first exposure, according to the CDC, but that period can be as long as 14 days. It can also take several days after exposure to get a positive result on a Covid-19 test, because there needs to be enough of the virus in your system to detect.
“Testing someone a day or two after an exposure has extremely limited value, since a negative test doesn’t rule out the possibility that they’ve been infected,” Dr. Matt Binnicker, director of clinical virology at the Mayo Clinic, told Forbes in an email. Binnicker says he typically recommends people wait 5-7 days from exposure until getting tested, as this waiting period “increases the likelihood that the test will be positive if they’ve truly been infected.”
Even though Pence and other White House staffers get daily Covid-19 tests, that doesn’t mean that they haven’t been infected with the virus. The Vice President appears to have last seen the President on Tuesday, which means if he was exposed, he might not test positive until the weekend has passed. This caution should also apply to Democratic presidential nominee Joe Biden, who announced a negative test result today but was in the room with the President at Tuesday night’s debate.
But finding out who is positive is only one piece of the puzzle. The other question is who infected President Trump in the first place? Hope Hicks, a close advisor to Trump, had a positive test one day earlier, but that doesn’t necessarily mean she was the one who exposed the president. “This is an outbreak within a pandemic. So they need to do an outbreak investigation. That means looking at all of these folks in the White House and dial this back, where did the source come from?” says Kortepeter.
This is key when it comes to quarantine. It’s not enough for the President, the First Lady and Hicks to isolate themselves, Kortepeter says. Everyone who has worked around them in the White House needs to do the same. “Until you have a better understanding of the dynamics of spread here and who actually has been at risk,” he says, “then you really need to essentially shut the place down.”
Kortepeter also says that Joe Biden needs to take precautions, due to the Presidential debate Tuesday night. “It looked like they were far apart, so he probably doesn’t need to quarantine,” he says. “But they were in an indoor environment with a lot of forceful, loud talking for an extended period, therefore, I think it would be prudent for him to be cautious, get tested regularly, and wear a mask to minimize risk of spread, just in case.”
Dr. Howard Koh, former United States Assistant Secretary for Health in the Obama administration, echoes Kortepeter’s recommendation that White House staffers lock down, and adds that the Trump administration’s response needs to go even further: “Timely and appropriate medical care, and aggressive health interventions around them—involving contact tracing, testing, isolation, quarantine and more—must begin immediately,” he says. “Administration leaders also need to step up promotion of measures such as universal mask wearing and social distancing for all.”
This article has been updated since initial publication to include new information.