The Centers for Disease Control and Prevention wants people to wear a mask at all times in public.

New guidelines released Friday advise that the mask use is needed to help slow the spread of the novel coronavirus that causes COVID-19.

We now know from recent studies that a significant portion of individuals with coronavirus lack symptoms and that even those who eventually develop symptoms can transmit the virus to others before showing symptoms, the CDC said in a statement Friday. It continued:

This means that the virus can spread between people interacting in close proximity for example, speaking, coughing, or sneezing even if those people are not exhibiting symptoms. In light of this new evidence, CDC recommends wearing cloth face coverings in public settings where other social distancing measures are difficult to maintain (e.g., grocery stores and pharmacies) especially in areas of significant community-based transmission.

The announcement marks a reversal of sorts for public health officials, who previously recommended people only wear a mask if they suspected they were sick, or were taking care of someone believed to be sick.

While many Asians countries and the Czech Republic have already made the wearing of masks mandatory, U.S. officials delayed, in part because many masks offer only modest protection against the virus, giving a false sense of security. Officials also were concerned about diminishing the availability of the better-designed masks, such as N-95s, for health care workers.

As recently as March 31, Surgeon General Jerome Adams said during an appearance on Fox & Friends that he was not recommending masks for healthy people.

The CDC emphasized that the new rules are an addition to social distancing measures, not a substitute for them. Social distancing and diligent hand-washing remain far more effective at stopping the spread of disease than wearing masks.

Dont rush out to buy a mask; leave the N-95s and other surgical masks for health care providers who desperately need them. Heres how to make your own mask at home .