The CDC’s face mask guidance issued on May 13, 2021 offered a glimmer of hope that the pandemic’s end was near, but that guidance has also caused confusion, anger, and worry.

The guidance, announced amid a decrease in coronavirus cases and an increase of vaccine eligibility to everyone 12 and older, came with some confusion.

We explain the new guidance to provide clarity on what precisely it all means.

Why now?

It was not entirely clear what prompted the new guidance. Cases, hospitalizations, and deaths have been trending downward in the United States for weeks.

But the United States is still recording more than 24,000 cases and about 500 deaths each day from COVID-19. That is the lowest level in the last 10 months, Gregory Poland, an infectious diseases expert who heads the Mayo Clinic’s Vaccine Research Group in Rochester, Minn., said May 18 in a podcast. And only 38 percent of the total population was fully vaccinated by May 20, according to the CDC.

Does this mean masks are no longer recommended anywhere?

The federal agency’s directive is that fully vaccinated people no longer have to wear masks indoors.

But the directive was not detailed about masking in certain settings, including schools.

The directive also advised fully vaccinated people to wear a mask when visiting health care facilities, while flying or taking public transit, and in congregate settings such as homeless shelters, as well as prisons or jails.

People who are not vaccinated should only go mask less when going for a walk, run or bike ride, or attending a small outdoor gathering where everyone else is fully vaccinated. At all other times, unvaccinated people should wear masks.

All people regardless of vaccination status must continue to wear masks on planes and public transportation like trains or buses, or when required to do so by federal, state, or local law.

Businesses can also continue to mandate masks.

What does this mean for local mask mandates?

The CDC advice does not override mask orders issued by states, counties, or cities.

What is the science behind the guidance?

Most people who are vaccinated against COVID are well protected, but it is important to note that the protection is not 100%.

The Moderna and Pfizer vaccines are about 94% effective, and while the Johnson & Johnson vaccine is 100% effective at reducing hospitalization and death, it is 66% to 72% effective against all COVID-19 infections.

What about kids?

Children who have not been vaccinated should still wear masks and keep 6 feet apart.

The CDC recommends masks for children aged 2 and older in public settings and when with people outside their household. Masks are also advised in schools.

How can you know if someone is vaccinated?

You will not.

The Biden administration has said there will be no federal mandate for a single vaccination credential, leaving the issue of whether to require evidence and how to police it to local governments and the private sector.

The bottom line

While the CDC has relaxed its direction for mask wearing among fully vaccinated people, it remains important to wear masks to protect the people around you.

You should maintain wearing masks in indoor locations, crowded areas, and places with people outside your household whose vaccination status is unknown. You should also mask up if you come in frequent contact with people who are high risk or immunocompromised.

Experts say it is crucial to wear masks, even after being vaccinated, until the prevalence of the disease has been greatly reduced.