LAS VEGAS >> Masks are back in Las Vegas, after regional health officials today cited a rising number of coronavirus cases and advised everyone — vaccinated or not — to wear facial coverings in crowds and indoor places.

The recommendation from the Southern Nevada Health District isn’t a requirement. But it affects casinos, concerts and clubs where business has boomed since restrictions were lifted and the state fully returned pandemic control measures to counties about seven weeks ago.

“Both vaccinated and unvaccinated individuals should wear masks when they are in crowded public settings … such as grocery stores, malls, large events and casinos,” Dr. Fermin Leguen, the region’s chief health officer, told reporters.

He said the district doesn’t have authority to make masks mandatory, leaving that question to the state, county and cities.

Vaccine clinics and testing are continuing at sites around the region, Leguen added.

Vaccination rates have stalled in recent weeks in Nevada, a state with libertarian leanings where health officials reported Friday that about 55% of residents 12 years and older have received at least one dose of COVID-19 vaccine. Statewide, about 46.3% are fully vaccinated.

Nationally, 68% of adults have received at least one dose of vaccine, according to the Centers for Disease Control and Prevention.

An official with the union representing 60,000 Nevada casino employees issued a statement noting the risks posed to workers by people who are not vaccinated.

Culinary Union official Geoconda Argüello-Kline pointed to CDC data that more than 97% of people who have been hospitalized recently with COVID-19 have not received a vaccine.

The mask recommendation in Las Vegas came after Nevada health officials on Thursday reported 938 new cases of COVID-19 statewide — the biggest one-day coronavirus case jump since February — and 15 new deaths.

It also followed a call from the public health chief in Los Angeles for Californians to rethink plans to travel to Nevada until COVID-19 case numbers in the Silver State decrease.

Weekend visitors from Southern California have in recent months jammed Interstate 15, the main route for the 270-mile (435-kilometer) trip between Los Angeles and Las Vegas.

“I do want to recommend, especially if you’re unvaccinated, reconsider traveling to places where the seven-day COVID-19 case rates are increasing or high like Nevada, our neighbor,” Dr. Muntu Davis told Los Angeles County commissioners on Tuesday.

Davis also recommended using masks in indoor spaces, regardless of vaccination status.

Nevada Gov. Steve Sisolak’s chief of staff, Michelle White, responded during a video conference call with reporters on Thursday with a suggestion that people travel to Nevada and get vaccinated.

“That’s why we are working to make sure there are vaccination and testing locations located on places like the Las Vegas Strip. That is open any individual, workers … visitors,” White said. “We have all three vaccines offered, including the one shot. If someone is coming from out of state, that can be more convenient and we certainly encourage everyone to do so.”

The Department of Health and Human Services said test positivity, a key marker of the percentage of people found to be infected among those tested for the virus, had tripled from 3.4% five weeks ago to 10.9% on Thursday.

The positivity figure reported by the state Department of Health and Human Services was 12.3% in the Las Vegas area.

The number of new cases reported Friday in Nevada was 866, and six new deaths. That brought to 5,758 the number of lives lost in the state to COVID-19 since March 2020.

Most cases and deaths in Nevada during the pandemic have been in the Las Vegas area, home to 2.3 million people and host to tens of millions of visitors per year.

On Friday, health officials in Washoe County said they had no plans to implement mask requirements or recommendations because the virus hasn’t surged in the Reno-Sparks area to the extent it has in Las Vegas.

Elsewhere, local officials from Lander County and Elko have recently focused on passing pre-emptive resolutions against vaccine passports.