WASHINGTON - The White House is expected to urge Americans to begin wearing cloth masks or face coverings in public to help prevent the spread of the novel coronavirus, in a reversal of its earlier recommendations, according to a federal official involved in the response.

The announcement could come as early as Thursday.

White House coronavirus task force officials have been considering whether to recommend that face coverings be routinely worn in public because of increasing evidence that infected people without symptoms can spread the virus, according to internal memos and new guidance provided to the White House by the CDC.

"In light of these new data, along with evidence of widespread transmission in communities across the country, CDC recommends the community use of cloth masks as an additional public health measure people can take to prevent the spread of virus to those around them," according to the guidance, a copy of which was obtained by The Washington Post.

The recommendations represent a major change in official CDC guidance that healthy people don't need masks or face coverings. The memos and guidance make clear the coverings under discussion are not medical masks, such as N95 respirators or surgical face masks, which are needed by front-line health-care workers and are in extremely short supply. Those must continue to be reserved for health-care workers and other first responders, they say.

The memos and guidance were drafted in recent days by the CDC and sent to officials at the Department of Health and Human Services and the White House coronavirus task force for consideration of masks as an additional measure to slow the pandemic.

Simple cloth masks that cover the mouth and nose can prevent virus transmission from individuals who are infected but have no symptoms when they are out buying groceries, the guidance states. It makes clear the cloth covering is not intended to protect the wearer, but to prevent the spread of the virus from the wearer to others.

It noted the face coverings could be made at home at a low cost.

The face coverings should not be used on young children under age 2, anyone who has trouble breathing, or is unconscious, incapacitated or otherwise unable to remove the cover without assistance, the guidance states.

CDC considering recommending general public wear face coverings in public

CDC's memos have noted that widespread public use of masks is not culturally accepted in the United States the way it is in many Asian countries, where face coverings helped reduce the spread of the virus.

Wearing cloth masks in public would be an additional community mitigation tool, according to the memos. Social distancing of at least six feet is still recommended even when wearing a mask. One memo drafted Thursday noted that people "generate respiratory aerosols when speaking, coughing and sneezing" that can be inhaled by nearby individuals.

A CDC report last week on asymptomatic infections among residents at a skilled nursing facility in the Seattle area found that of 23 residents who tested positive for the novel coronavirus, 13 were asymptomatic or pre-symptomatic on the day of testing.

Infectious-disease experts say asymptomatic transmission may be playing a larger role in the outbreak than previously thought, but just how big remains unknown. Studies are underway at the CDC and elsewhere to better understand such transmission.