Expert: Getting tested for Thanksgiving? A negative result is no guarantee


Thanksgiving and the ongoing national surge in cases has driven a major increase in demand for coronavirus tests.

Many people are getting tested before getting together with loved ones for Thanksgiving as an added layer of security.

But public health experts say that a negative test result is not a guarantee that you will remain negative for the virus, and people should not let their guard down.

“Having a negative test in advance is not an assurance, because one of the things that’s become clear with this virus is you can test negative and then in a few hours later if you were exposed you can start to become infected,” said Charles Haas, professor of environmental engineering at Drexel University.

Coronavirus tests will tell you if you had a detectable level of the virus in your system at the point in time that you took the test, but the virus takes some time to incubate within the body.

“If you were exposed, you could go from having no detectable virus to having detectable virus in, let’s say, 12 hours. So it can shoot up fairly rapidly,” said Haas.

Results can often take several days as well, which means many people are planning to get tested days before their get together, which creates a larger window of time where you could potentially be exposed to the virus, especially if you are traveling or flying in order to celebrate with others.

“A negative test is interesting, but it’s not a safe passage,” said Haas.

He advises that regardless of whether or not everyone in your group has received a negative test result, you should still take precautions.

“So air purifiers, definitely wear a mask. Keep the windows open if you can.”

Better yet? “Try to avoid it, really. Try to avoid it.”