NEW YORK (CBSNewYork) – Mayor Bill de Blasio announced Thursday a new recommendation that all New Yorkers should cover their mouths and noses when going out in public to slow the spread of coronavirus.

“We’re adding a new important point and we’re advising New Yorkers to wear a face-covering when you go outside and we’ll be near other people,” he said.

The push does not mean to use surgical masks or other personal protective equipment that are prioritized for medical staff in hospitals dealing with COVID-19 patients in hospitals and ICU.

Instead, people should immediately begin wearing bandanas, scarfs and home-made facial coverings, even among those who are not showing any symptoms of coronavirus infection.

WATCH: Mayor Bill De Blasio Holds Briefing On Coronavirus Pandemic

De Blasio said the decision was driven by city health officials looking at the results of a study published on April 1.

“I’ve come to a conclusion that it’s time to advise New Yorkers to do something different,” he said. “I want to emphasize what I’m about to tell you is very very important, but it does not in any way change the basic guidance that you received now over many weeks.”

CORONAVIRUS PANDEMIC

It’s a dramatic shift in guidance after weeks of authorities telling people that masks should only be used if people are sick or coughing.

The change in the public recommendation is not meant to replace the social distance rules that have been in place since last month.

“The reason for this guidance is because the studies are showing that some asymptomatic people some pre-symptomatic people appear to actually be transmitting this disease,” said de Blasio. “We don’t have perfect evidence. It doesn’t conform with what the initial information showed us weeks ago, but it does seem to be more and more evident.”

While such covering would not protect someone from catching the virus from others, it could minimize an infected person spreading the virus to others.

“Now remember, community spread – with the projections we’ve told you – over half of New Yorkers will contract this disease,” the mayor said. “Do something homemade, not something professional, not something from the supplies we need for our heroes. That’s going to help protect everyone.”

CORONAVIRUS HELP: How To Make Your Own Facial Mask At Home

The homemade coverings could be reusable after a cleaning, according to the city’s health commissioner, Dr. Oxiris Barbot.

“What I recommend is that for these face coverings to be used for a day, and then you can handwash them in soap and water,” she said. “The important thing is that they dry completely.”

The mayor says the city did not move on this recommendation earlier because the science was just not there yet.

“In a perfect world, yes, we should have probably done this sooner,” said Dr. Michelle Blackwood, of RWJ Barnabus Health/Rutgers.

She says countries that went to masks early, like South Korea, got on top of the virus sooner.

“Will this effectively help people, just, let’s say, having a scarf across your face?” CBS2’s Dick Brennan asked.

“Quite frankly, anything that puts a barrier between you and particles is good. The problem is that the particles are extremely small and it can get in between the scarf. The other thing, perhaps, the scarf needs to be taken off correctly, so that you don’t spread it if it catches any particles,” Blackwood said.

The mayor says there won’t be any enforcement on covering up. He says he needs that for other priorities.

CORONAVIRUS: NY Health Dept. | NY Call 1-(888)-364-3065 | NYC Health Dept. | NYC Call 311, Text COVID to 692692 | NJ COVID-19 Info Hub | NJ Call 1-(800)-222-1222 or 211, Text NJCOVID to 898211 | CT Health Dept. | CT Call 211 | Centers for Disease Control and Prevention

Much of the country seems to be split on whether the general public should be wearing masks outside the home. The hashtag #Masks4All is a social media movement quickly gaining steam. It encourages anyone and everyone to cover the mouth and nose when out in public.

The PSA is largely credited with starting the movement at Masks4All.org. It was created in Prague and has been viewed more than 1.8 million times.

The narrator in the PSA stresses the group’s slogan: “When we both have a face mask, I protect you, you protect me.”