States that instituted mask mandates reported a decline in COVID-19 hospitalizations, according to a new report from the Centers for Disease Control and Prevention.

Researchers analyzed hospitalization data in 10 states with mask mandates between March and October of last year. They found a 5.5% decline in weekly COVID-19 hospitalizations among adults, compared to the period before the mandates were implemented.

In addition to reducing virus exposure and transmission, masks are part of a multi-pronged strategy to "reduce strain on the health care system," the researchers note, adding that masks likely have a direct effect on COVID-19 illness and death.

The researchers did not examine whether other policies, such as school closings and physical distancing recommendations, contributed to the decline. The results were published Friday in the CDC's Morbidity and Mortality Weekly Report.

-ABC News' Eric Strauss contributed to this report.

Former Yankees pitcher Mariano Rivera will join Mayor Bill de Blasio at Yankee stadium Friday afternoon to celebrate the opening of a mass vaccination site at the stadium.

The site, which will be reserved for residents from the Bronx, will be open daily from 8 a.m. to 8 p.m. and is meant to ensure that Black and Latino residents have equal access to the vaccine. It will be open 24 hours a day when more vaccine supply is available, according to the mayor.

"I think it’s going to be extraordinary," de Blasio told WNYC on Friday. "We are going to have a wonderful celebration of this place opening up. I will be joined by Mariano Rivera, who will help us get this message out. This is for people of the Bronx, people who haven’t been able to get vaccinated."

Bronx residents who want to book an appointment should go to  or call 1-833-SomosNY.

-ABC News' Aaron Katersky contributed to this report.

So far, 8% of the U.S. population has received one or more doses of COVID-19 vaccines, according to official figures released Friday by the U.S. Department of Health and Human Services.

In total, 35,203,710 vaccine doses have been administered nationwide. About 27.9 million people -- 8% of the population -- have received one or more doses, while 6.9 million people -- 2% of the population -- have received two doses.

ABC News' Josh Margolin contributed to this report.

U.S. President Joe Biden's administration announced Friday that 1,110 active-duty military personnel will be deployed across the country to assist with COVID-19 vaccinations.

The announcement was made during a press briefing at the White House in Washington, D.C.

The troops, sourced from across the U.S. Army, Air Force, Navy and Marine Corps, will be split up into five teams of 222 personnel that will be assigned to support five COVID-19 vaccination centers run by the U.S. Federal Emergency Management Agency (FEMA), according to a fact sheet on the initiative released by the Office of the Secretary of Defense.

FEMA and the U.S. Department of Defense will jointly determine when the troops are no longer needed for vaccination support, according the fact sheet.

ABC News' Matt Seyler contributed to this report.

An accommodation facility for refugees in the German city of Cologne has been hit by new, more contagious variants of the novel coronavirus, city officials said.

At least 41 residents of the Herkulesstrasse facility have tested positive for COVID-19. Variants first identified in South Africa or Brazil have been detected in 31 of them so far, according to a statement from the city government on Sunday.

At least 16 staff members at the facility have also tested positive for COVID-19, with the South Africa variant detected in 11 of them so far. Variant analysis is still pending on the other five, according to the statement.

All residents of the facility have been under quarantine since Friday, while the site has been under surveillance since Sunday. Entry into the refugee accommodation center, which can house up to 600 people, is currently banned, according to the statement.

The first known COVID-19 cases were confirmed among two employees at the facility about 10 days ago, while the first case of a variant was confirmed last week, according to the statement.

Dr. Harald Rau, head of Cologne's public health department, said the detection of variants at the refugee accommodation center "is a clear alarm signal for all of us."

"I ask all people in Cologne to avoid contact even more consistently than before and to follow the distance and hygiene rules of infection protection," Rau said in a statement Sunday.