CDC urges Americans to wear masks indoors as COVID-19 surge intensifies

The U.S. Centers for Disease Control and Prevention Friday called for universal mask-wearing and urged Americans to wear face masks indoors amid an alarming surge in COVID-19 cases around the country.

“With colder weather, more time spent indoors, the ongoing U.S. holiday season, and silent spread of disease, with approximately 50% of transmission from asymptomatic persons (2), the United States has entered a phase of high-level transmission where a multipronged approach to implementing all evidence-based public health strategies at both the individual and community levels is essential," the health agency wrote. 

The new guidance follows an urgent recommendation by the CDC for Americans to stay home over the upcoming holiday season and to consider getting tested for COVID-19 before and after if they do decide to travel. 

RELATED: CDC urges Americans to stay home for holidays

The CDC said that the best way to stay safe and protect others is to cancel travel plans and stay put. That’s the same advice the agency issued over Thanksgiving, but many Americans traveled anyway. With COVID-19 cases and deaths continuing to rise, the CDC added the testing guidance.

Specifically addressing holiday travelers, the CDC wrote, “For 14 days after arrival, travelers should avoid close contact with persons at higher risk for severe COVID-19–associated outcomes and wear masks in household spaces shared with those who did not travel.”

Wearing masks to reduce the risk posed by the coronavirus pandemic, commuters step in and out of a Metro train car at the Metro Center station December 02, 2020 in Washington, DC. (Photo by Chip Somodevilla/Getty Images)

The health agency added that in order to mitigate the spread of the ongoing pandemic, “universal mitigation efforts are needed.” 

The CDC also called on local authorities to implement a community-level plan for distribution of face masks. 

“Consistent and correct use of face masks is a public health strategy critical to reducing respiratory transmission of SARS-CoV-2, particularly in light of estimates that approximately one half of new infections are transmitted by persons who have no symptoms,” the CDC wrote. 

RELATED: Coronavirus-related face masks protect the wearer, too: CDC says in updated guidance

In November, the CDC updated its guidance on face masks to indicate that they offer protection to the wearer as well as others. 

The CDC said early research supports community masking to lower virus spread, particularly when it’s estimated that more than half of transmissions stem from asymptomatic people. The agency also explained the filtration power of masks, writing, “Studies demonstrate that cloth mask materials can also reduce wearers’ exposure to infectious droplets through filtration, including filtration of fine droplets and particles less than 10 microns.”

Coronavirus transmission at home is a common occurrence, per a recent CDC report. The agency assessed 101 households in Nashville, Tenn., and Marshfield, Wis., from April to September. Over half (53%) of all household contacts were infected and “secondary infections occurred rapidly, with approximately 75% of infections identified within five days of the index patient’s illness onset,” the report said.

The number of Americans hospitalized with COVID-19 hit an all-time high in the U.S. on Thursday at 100,667, according to the COVID Tracking Project. That figure has more than doubled over the past month, while new daily cases are averaging 210,000 and deaths are averaging 1,800 per day, according to data compiled by Johns Hopkins University.

The Associated Press and FOX News contributed to this story.