Updated federal guidance for the first time in weeks has lifted an indoor face mask recommendation in Arizona's most populated county.

The Centers for Disease Control and Prevention designated Maricopa County at the "low" COVID-19 community level on Thursday, meaning face masks are not explicitly recommended for most people in indoor public areas.

Maricopa County had been designated at the "high" level since July 14. The guidance is updated weekly and ranks counties as low, medium and high, or green, yellow and orange.

Counties that were designated at the "high" level on Thursday were Mohave, Navajo, Apache, Yuma and La Paz. The CDC recommends residents in counties with a "high" designation wear face masks when in public areas indoors regardless of vaccination status.

In addition to Maricopa County, other counties designated low as of Thursday are Yavapai, Pinal and Greenlee counties. Coconino, Gila, Graham, Cochise, Santa Cruz and Pima counties are all in the medium community level.

Nearly 42% of counties across the country were designated as "high" as of Thursday's update.

Navajo and Apache counties have been designed as high since June 9. La Paz has been ranked high every week since June 23 (except for July 7), Mohave since June 30 and Yuma since July 14.

The metrics are based on a county’s COVID-19 hospital bed use, COVID-19 hospital admissions and case rates for the virus over the past week.

COVID-19 Aug. 4 update: Cases increase by 15,034, with 74 new known deaths

Face masks are not explicitly recommended for residents in counties at the medium level except for certain people, including those who are immunocompromised, at high risk for severe disease, or have a household or social contact at high risk for severe disease.

The CDC also recommends "enhanced prevention measures in high-risk congregate settings" in communities designated at the medium level.

Areas of the country with large swaths of counties in the "high" designation include Florida, Kentucky, West Virginia and Louisiana.

While face mask recommendations have changed, a CDC map of COVID-19 virus transmission indicates that transmission remained high in 94% of U.S. counties as of the most recent update.

Reported COVID-19 cases in Arizona have continued to increase at a relatively consistent weekly pace.

State health officials on Wednesday added 15,034 new COVID-19 cases and 74 new known deaths over the weeklong period ending July 30. June and July have seen relatively similar weekly case additions.

Case counts are still far below the winter, state data shows. Case numbers in recent months likely are not showing the full picture of infections as many more people have used at-home test kits and may not report positive results to their doctors or county health departments.

Arizona, like other states, is seeing an ongoing case increase largely driven by two contagious subvariants of the virus, BA.4 and BA.5, with BA.5 the more dominant of the two.

The contagiousness of BA.5 likely is contributing to reinfections and infections of people who are fully vaccinated and boosted given its contagiousness and ability to evade antibodies.

Reach the reporter at Stephanie.Innes@gannett.com or at 602-444-8369. Follow her on Twitter @stephanieinnes.

Reach the reporter at Alison.Steinbach@arizonarepublic.com or at 602-444-4282. Follow her on Twitter @alisteinbach.

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This article originally appeared on Arizona Republic: New CDC guidance lifts mask recommendations in Maricopa County