Just as many Americans are getting used to being unmasked again, the World Health Organization, Los Angeles County and Illinois’ governor — all concerned about the rapidly spreading COVID-19 delta variant — are urging even vaccinated people to cover their faces in public.

Those recommendations, however, clash with guidance from the Centers for Disease Control and Prevention, which said last month that fully vaccinated Americans can shed their masks indoors and outdoors. The updated guidance prompted states that still had mask restrictions in place to drop them.

CDC Director Dr. Rochelle Walensky said Wednesday that the agency stands by its guidance, but she added that the CDC respects the decisions of state and local leaders trying to protect their communities. 

“There are areas of this country where about a third of people are vaccinated — they have low vaccination rates — and there are areas that have more disease in the context of people not being vaccinated,” Walensky told NBC’s “Today” show.

The delta variant, which studies show is about 60% more contagious than the alpha strain that was first detected in the United Kingdom, now accounts for about 26% of new infections in the U.S., the CDC said Tuesday. Walensky has said she expects the delta variant to become the country’s dominant strain. Dr. Anthony Fauci, the federal government’s top infectious disease expert, last week called the variant the “greatest threat” to the country’s attempt to eliminate COVID-19.

After steadily falling for months, new daily cases of COVID-19 ticked up by 6.4% from June 19 to Monday, CDC data show. Cases are on the rise in 15 states over the past two weeks, according to The New York Times. Of those states, 11 have fully vaccinated less than half their residents. 

Los Angeles County health officials released a statement Monday “strongly” recommending that everyone — regardless of vaccination status — wear masks in indoor public places due to the fast-spreading delta variant.

“Until we better understand how and to who the Delta variant is spreading, everyone should focus on maximum protection with minimum interruption to routine as all businesses operate without other restrictions,” the statement said.

In Illinois, Gov. JB Pritzker, also concerned about the mutation, is encouraging people to wear masks indoors again, too.

“This virus is very much present, infecting people, hospitalizing some and tragically, killing others every day,” he said Monday.

WHO officials said Friday that even fully vaccinated people should wear masks, socially distance and take other precautions. 

“People cannot feel safe just because they had the two doses,” Dr. Mariangela Simao, WHO assistant director-general for access to medicines and health products, said at a news briefing. “They still need to protect themselves.”

Walensky said the WHO recommendation was made with the entire world in mind, noting that only about 15% of people have received at least one vaccine dose. 

“Here in the United States, we're fortunate we have three vaccines that we know are safe and effective,” she said. “We have two-thirds of the adult population that is fully vaccinated and really quite protected from the variants that we have circulating here.”

Studies suggest the Pfizer and Moderna vaccines offer protection against delta and other variants. 

Walensky said the CDC is awaiting data about the Johnson & Johnson shot, but that “we have every reason to believe” it, too, will perform well against the delta variant. She based her prediction off other studies involving the Johnson & Johnson vaccine and variants of concern, as well as how the AstraZeneca vaccine, which uses similar technology, has performed against the delta strain in other countries.