KANSAS CITY, Mo. — If you get a negative result on a COVID-19 test, are you cleared for travel?
The answer: Not exactly. It all depends on when you were tested.
For example, let's say on Day 1, you were exposed to COVID-19 but didn't realize it. You happen to get tested the next day, but you don't have enough viral load in your system for it to register.
Then, anytime between Day 3 and Day 5, you enter the incubation phase. Although you're not showing any symptoms, you're still contagious. Health experts believe you can transmit the virus 24 to 72 hours before you experience any symptoms.
However, on Day 4, you get the results from your test back and they're negative. Doctors call the result of that test a snapshot in time — in this scenario, from two days ago. And while you might have been negative then, you're not now.
Still, you don't know that. So on Day 5, you go to your grandmother's house for Thanksgiving.
Then, on Day 9, you get the call: grandma, your parents, your sister — they're all feeling sick.
Day 10 rolls around and you get tested again, only to find out you're indeed positive and have been for days.
"We know that the test results really are reflective of that moment in time," said Ginny Boos, Saint Luke's director of infection prevention. "If you've had some exposures between the time that you were tested and afterward, then again, it's that timeline. You really do have to think about the timeline. You could be negative one day and actually then be positive the next day."
Health experts say the best way to avoid exposing loved ones is to stay home. And if you're determined to visit family over the holidays, the next best step is to make sure everyone in attendance has quarantined for 14 days beforehand.