Health experts advised against traveling for Thanksgiving due to the coronavirus pandemic, worried that travel between different parts of the country could further spread the illness amid surging cases and rising hospitalizations.
Despite the warnings, millions of Americans did travel: The Transportation Security Administration (TSA) processed over 6 million fliers during the holiday weekend, the most since the pandemic began.
If you traveled or gathered with people outside of your immediate household, it's not too late to prevent spreading the virus now.
"If you’re young and you gathered, you need to be tested about five to 10 days later," said Dr. Deborah Birx, the coordinator of the White House coronavirus task force. "You need to assume you’re infected and not go near your grandparents and aunts and others without a mask."
Is testing the best way to stay safe?
While testing can help identify cases of the virus, it has some drawbacks: Tests can't always detect the virus if you're early in the illness, and people who are asymptomatic may not get tested. There's also the risk of false negatives, which can give people a misplaced sense of safety.
"If you traveled for Thanksgiving, you need to make sure you don't spread any coronavirus you picked up either traveling back and forth or at the actual gathering," said NBC News medical correspondent Dr. John Torres. "The best way to do this is by quarantining for 14 days once you return and (this) should especially be done if you were in a higher risk environment, meaning no mask wearing or social distancing, even for a short time period."
Dr. Iahn Gonsenhauser, chief quality and patient safety officer at The Ohio State University Wexner Medical Center in Columbus, said that the demand for tests may make it complicated for everyone to get a test, advising a quarantine instead.
"We anticipate having a huge crush of demand for post-Thanksgiving testing, so it's going to be challenging for many areas of the country to keep up with that demand," Gonsenhauser said. "We may be faced with long wait times and people who are actually symptomatic, then having trouble getting tested."
Gonsenhauser said that another complicating factor is how long the virus can incubate in the body and how long it takes for a test to be able to pick up the virus, making quarantine a safer option.
"It can take up to seven days after an exposure for a test to pick up an infection," he said. "While it's generally much quicker than that, the fact that it can take so long creates a big opportunity for potential false negatives. If you traveled two days ago and you were exposed, and you get tested today, that test may be negative, when in fact you are a positive carrier. If that happens, you'll be back at work or at your daily life, potentially an asymptomatic carrier who has the potential to expose and infect others."
Gonsenhauser also added that people should keep their state travel policies in mind when returning home.
"There are a number of states that are requiring self-quarantine for up to 14 days if a traveler spent more than 24 hours in a state that has a positivity rate that's higher than certain levels," Gonsenhauser said.
When should people get tested?
Torres said that getting tested "could help" identify cases of coronavirus but it "needs to be done correctly" to have an impact.
"Getting tested immediately after returning (from Thanksgiving travel) won't help, since it takes a while for the virus to build up in your body," said Torres, who agreed with Birx's timeline for when a test should be performed. "A PCR test is the most accurate, especially if you aren't having any symptoms. If you test positive, then you'll need to isolate yourself and notify those you were around on your trip. If you test negative, it’s not a free pass to go out and about since the incubation period for the virus is up to 14 days and you might test positive or develop symptoms just a few days after that initial test."
Dr. Ted Cohen, an infectious disease epidemiologist and professor at the Yale School of Public Health in New Haven, Connecticut, said that anyone who is symptomatic should be tested "as soon as possible," but those who are showing no symptoms should wait at least a few days before getting tested.
"Given the delay between exposure and reliability of test results, it is rational for individuals with symptoms to self-quarantine for a few, say about five, days after travel or potential exposure, then seek testing," Cohen said.
Who should get tested?
Cohen said that anyone who has "gathered with others outside their immediate household should be tested."
Gonsenhauser agreed with Birx's comment that everyone should act as if they have been infected.
"The order of the day is for almost everybody to assume that they've been exposed," he said. "Whether you have or haven't, whether you're aware of it or not, an abundance of caution would suggest that people assume that they had an exposure, while traveling or while visiting outside of their household."
What if you test positive?
If you do test positive for the virus, Gonsenhauser said the most important thing you can do is maintain a solid two-week quarantine and be sure to cooperate with contact tracers.
What if you test negative?
Given the flaws of tests, like the chance for false negatives and the length of time it can take for the virus to incubate, Torres said that people should still take precautions even if they receive a negative test result.
"You still need to take precautions (as to) not expose others around you," he said. "(That) includes staying home as much as possible, and when you are out and about, wearing a mask and social distancing. Remember, just because no one around you seemed sick doesn’t mean they didn’t have the virus and they very well could have spread it to you over the holiday."