St. Louis County in Missouri is mandating face masks for everyone over the age of 5 when indoors regardless of vaccination status amid the spread of the delta variant, officials announced Friday. 

Masks are also "strongly encouraged" for groups when outdoors. 

"We’ve lost more than 500 St. Louisans to COVID-19, and if our region doesn’t work together to protect one another, we could see spikes that overwhelm our hospital and public health systems," Dr. Fredrick Echols, acting director of health for the City of St. Louis, said Friday. 

St. Louis County reported 241 new confirmed cases of COVID-19 on Wednesday, bumping the 7-day average up to 212, which is slightly higher than the level that it was at in mid-April. The county's average test positivity rate has risen to 9.4% over the past week, the highest it has been since late January. 

Statewide, cases are also reaching levels not seen since January as Missouri reported 2,865 new COVID-19 cases on Friday, according to a St. Louis Post-Dispatch analysis. 

CDC: DELTA VARIANT ACCOUNTS FOR 83% OF US CASES

Dr. Faisal Khan, acting director of the St. Louis County Department of Public Health, said that vaccines are the "best way to stop the fast-spreading Delta variant of COVID-19."

"We are relentlessly committed to making vaccinations more accessible and convenient," Dr. Khan said Friday. "In the meantime, we need everyone, vaccinated or not, to wear masks in crowded indoor settings."

Just over half, 50.2%, of adults in Missouri are fully vaccinated, while 57.5% have received at least one dose of a vaccine. 

Los Angeles County reinstated a mask mandate last week amid surging COVID-19 cases. (Irfan Khan / Los Angeles Times via Getty Images)

Local officials in other parts of the country with surging cases have already reinstated mask mandates.

Los Angeles County officials announced last week that everyone must wear masks indoors regardless of vaccination status. 

Clark County officials announced earlier this week that all employees in Las Vegas must wear masks indoors, but stopped short of implementing a mandate for the general public. 

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The CDC announced on May 13 that vaccinated Americans no longer have to wear masks, but the Delta variant's surge has caused some local officials to rethink that guidance. 

Dr. Rachel Walensky, the director of the CDC, said this week that her agency's mask guidance hasn't changed, but that "communities and individuals need to make the decisions that are right for them based on what's going on in their local areas."

"If you’re in an area that has a high case rate and low rates of vaccination where Delta cases are rising, you should certainly be wearing a mask if you are unvaccinated," Dr. Walensky said at the White House Thursday. "If you are vaccinated, you get exceptional protection from the vaccines. But you have the opportunity to make the personal choice to add extra layers of protection if you so choose."