LAS VEGAS (KLAS) — Nevada will adopt the Centers for Disease Control and Prevention’s (CDC) updated mask guidelines on Friday, health leaders said Tuesday.

The CDC reversed course Tuesday, saying fully vaccinated Americans in areas with “substantial and high” transmission should wear masks indoors when in public as COVID-19 cases rise. Most of Nevada falls into those two risk categories.

Nevada’s new mask guideline will go into effect at 12:01 a.m. Friday. This overrides Clark County’s employee mask mandate, which went into effect nearly two weeks ago.

The Nevada Gaming Control board added issued guidance Tuesday afternoon, saying resorts must make sure “all employees, patrons, and guests properly utilize face coverings” indoors. Casinos must also put up signage indicating masks are required, the notice said.

“To allow communities and businesses in counties with substantial or high transmission time to implement the new requirements, today, Governor Sisolak issued Emergency Directive 047, which allows a three-day grace period to implement the new State mask mandate, meaning that Tuesday’s updates from the CDC will formally go into effect on Friday, July 30, 2021,” Nevada Health Response officials wrote in a statement. “Businesses and residents in counties with substantial or high transmission are strongly urged to adopt the changes as soon as possible.  “

During a news briefing Tuesday, CDC Director Rochelle Walensky said vaccinated people could spread the Delta variant more easily than previous versions of COVID-19.

The CDC’s website has a map showing counties with substantial and high transmission, including Clark County. Nearly all of Nevada is considered an area of high transmission.

The counties listed as having substantial or high transmission comprises nearly two-thirds of the country.

Clark County and Nevada remained places with high COVID-19 transmission and on the White House’s list of “areas of concern,” according to an updated report released Friday morning. A new report was not released Tuesday morning.

The Community Profile Report labels Clark County as an “area of concern” and a “sustained hot spot” for coronavirus transmission. Nevada was labeled as a “high transmission state.”

The number of new COVID-19 hospitalized patients in Nevada soared on Monday, as the state reported 1,124 new COVID-19 cases and 17 deaths in data released on Tuesday.

Nevada’s test positivity rate is now at 13.7%, up from 13.5% — and following Clark County’s steadily increasing rate of 14.9%.

As of Tuesday, 47% of Nevadans 12 or older were fully vaccinated, according to state data. In Clark County, that number was slightly lower at about 46%.

Regardless of vaccination status, all employees in students in K-12 schools across the country must wear masks indoors, the CDC said. This means Clark County schools will reopen Aug. 9 with a mask requirement in place for students, teachers and other employees.

Two weeks ago, Walensky said the pandemic had mainly became a “pandemic of the unvaccinated.” State health leaders said nearly all patients in Nevada hospitalized for COVID-19 are unvaccinated.