Minnesota's U.S. Sen. Tina Smith has tested negative Monday after announcing Sunday that she would quarantine after she was potentially exposed to COVID-19. 

The senator, who is running for re-election this November, tweeted Sunday saying a person at a campaign event last weekend tested positive for the coronavirus that day (Sunday). 

"The event was outdoors and masks were required, and while I was never in close contact with them, I'm getting tested and I am quarantining until I test negative," the Democrat said. 

On Monday, Smith tweeted that she tested negative and would be heading back to Washington, D.C.

Smith's Republican challenger Jason Lewis has quarantined twice after potentially being exposed to COVID-19 at least two times over the past few weeks, including after President Donald Trump visited Minnesota, but returned to the campaign trail after testing negative both times. 

The incubation period for the virus is 2-14 days, with health officials advising someone who has been in close contact with a COVID-positive person (being within six feet of them for a total of 15 minutes or more) to quarantine for two weeks, as people may still develop the virus despite having several negative tests.

The Minnesota Department of Health encourages anyone who has symptoms of COVID-19 to get tested for the virus right away. 

If you don't have symptoms but were exposed to the virus, MDH recommends quarantining and getting tested at day 5-7 after exposure in case you're asymptomatic (you could still spread the virus without knowing you have it). If you test negative, MDH encourages you to get tested again at day 12. Information on where to get tested in Minnesota can be found here. 

Here's the Center for Disease Control and Prevention's website for when someone should quarantine, as well as for how long.