The Centers for Disease Control and Prevention (CDC) released new guidelines today recommending that people in the US wear homemade face coverings to prevent the spread of the novel coronavirus.

“The CDC is additionally advising simple cloth coverings to help people who may have the virus and do not know it keep from from transmitting to others,” said US Surgeon General Jerome Adams in a press conference at the White House today.

“The CDC is additionally advising simple cloth coverings to help people who may have the virus and do not know it keep from from transmitting to others”

When cases of COVID-19 were first reported in the US in January, the CDC said that only health care providers and people who are acutely ill should wear face masks. Health care providers use surgical masks and N95 respirators, which filter out tiny particles in the air, to protect themselves when they’re working closely with sick patients.

The White House task force and the CDC have been re-evaluating their mask recommendations over the past few days. Research shows that people without symptoms can infect others, and that the virus may spread when people speak or breathe — not just when they cough or sneeze. “In light of this new evidence, the CDC recommends and the task force recommends people wear cloth face coverings in public settings where other distancing measures are difficult to maintain,” Adams said.

If people cover their faces with a cloth mask or another barrier, it may blunt the amount of virus-laden particles they release, experts say. There is limited evidence that these types of makeshift masks prevent the spread of disease, though some research shows that they do reduce the amount of particles a person wearing them spreads. Some experts say that they’re better than nothing. The CDC says people should continue to stay six feet apart when in public as much as possible, even if they’re wearing masks.

The US has a severe shortage of medical-grade masks, leaving doctors and nurses exposed to infection. In February, the US surgeon general warned that if the general public bought these masks, they put health care workers at risk. The new guidance stresses that members of the general public should not use surgical and N95 masks, because those should be reserved for health care workers. Instead, they should wear cloth masks or other makeshift face coverings.

Some cities and states, like Colorado and New York City, had already asked people to cover their faces when out in public.

#BREAKING: @GovofCO asks Coloradans to wear non-medical cloth masks or a scarf when going out in public for essential services.



Should cover your mouth & nose. Then, throw them in a warm wash when you return home #coronavirus #ColoradoMaskProject #InThisTogether pic.twitter.com/X6JqC7vQOp — CBSDenver (@CBSDenver) April 3, 2020

The White House response to the pandemic has been characterized by confusing, quick-changing policies and messaging around public health measures like masks and testing. Changes are expected during a crisis, but the federal government did not adequately prepare people for those changes.

The White House and President Donald Trump also continue to undercut messaging from the CDC. Trump said during today’s press conference that he wasn’t going to wear a mask. “This is voluntary. I don’t think I’m going to be doing it,” he said.

Based on current estimates, the US is on pace to have the worst COVID-19 outbreak of any country in the world.