WASHINGTON (NewsNation Now) — Dr. Deborah Birx, the coordinator of the White House Coronavirus Task Force, warned Americans Sunday to get tested for COVID-19 if they traveled for the Thanksgiving holiday and attended large gatherings.

Birx said, “assume you are infected.” She pleaded with Americans to do all they can to protect themselves and their families.

“We know people may have made mistakes over the Thanksgiving time period,” Birx said in an interview with CBS News. “If you’re young and you gathered, you need to be tested about five to 10 days later. But you need to assume that you’re infected and not go near your grandparents and aunts and others without a mask.”

The number of Americans who have tested positive passed 13 million Friday, according to Johns Hopkins University. Dr. Birx said in cases when mitigation measures aren’t in place, it’s up to individuals to ensure their own safety.

“To every American, this is the moment to protect yourself and your family,” she said. “So if your governor or your mayor isn’t doing the policies that we know are critical — masking, physical distancing, avoiding bars, avoiding crowded indoor areas — if those restrictions don’t exist in your state, you need to take it upon yourself to be restricted. You need to not go to these places. You need to protect your family now.”

As of Sunday, there were 155,596 new confirmed COVID-19 cases and 1,189 new deaths, according to Johns Hopkins University.