Part of White House Coronavirus Task Force, Dr. Deborah Birx, warned that Americans who attended large gatherings and traveled during Thanksgiving should assume they were already infected with COVID-19.

Birx added that they should be tested within the next few days. The COVID-19 coordinator said that they know people have made mistakes over the Thanksgiving time period.

Travelers need to be tested for COVID-19

Birx said that if you are young and you attended a gathering, 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," Birx was quoted in a CBS News report.

Birx said that it is best to avoid people with comorbidities.

Public health experts urged Americans to avoid any large family gatherings with the latest surge of COVID-19 infections.

There have been 13.2 million confirmed cases of COVID-19 in the United States, with over 266,000 Americans who have died from the pandemic.

Related story: One-Third of Parents Believe Family Thanksgiving Gathering Worth the COVID-19 Risk, New Poll Shows

Some governors and mayors have already imposed restriction on businesses and restaurants to mitigate the spread of the pandemic.

This is part of their response to the recent surge in cases and spike in hospitalizations across the country.

However, other have refused to implement mask mandates and are allowing bars and restaurants to remain open with less restrictions.

Birx said that it is up to every individual to take their own steps to protect themselves and in their families, particularly in places where mitigation measures are not implemented.

She added that this is the moment to protect your family.

"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." Birx was quoted in a CBS News report.

Birx noted that mask requirements have proven to be effective in fighting the spread of COVID-19.

However, public health experts are concern what could happen with infection rates after Thanksgiving.

Related story: Fauci Says Nation May See a Surge Upon Surge in COVID-19 Cases, No Relaxation in Restrictions

Democratic presidential nominee Joe Biden and his team has been discussing the pandemic as one of their top priorities.

Leaders of his coronavirus advisory board have also started joining in briefings with federal agencies to better prepare for the fight against the pandemic once Biden takes office.

Birx said it is critical that Biden's team begin examining data put by federal government on COVID-19 infections, as well as the spread of the virus.

Birx said that they want to discuss how the Biden administration see the data as the data is not helpful if it is not feasible.

She added that each group needs to see it the way it gives them action.

Birx said she sends briefing to Vice President Mike Pence daily on a daily basis.

However, she did not say when last briefed U.S. President Donald Trump.

Meanwhile, Fauci also warned that there could be a surge upon surge of COVID-19 cases due to Thanksgiving gatherings and travels despite recommendations from the Centers for Disease Control and Prevention.