As coronavirus vaccines and boosters proliferate in the United States, many millions of Americans are still subject to strict mask mandates in major cities and entire states — and on all public transportation, per a federal government mandate. 

But in many cases there's no clear plan to roll back mask rules. 

Washington, D.C., still has a mask mandate for indoor public places no matter the vaccination status. So does Los Angeles County.

Oregon has a mask mandate, regardless of vaccine status, for indoor settings and outdoor settings where social distancing isn't possible. 

Washington state mandates masks indoors and at outdoor events with 500 or more people. Illinois has a mask mandate for indoor settings. 

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Just that incomplete list of cities and states encompasses nearly 30 million people. 

The Centers for Disease Control and Prevention (CDC) also recommends that vaccinated people wear masks indoors in most places in the United States, guidance that is followed by local governments across the country. 

CDC Director Rochelle Walensky notably argued for mask-wearing last week by saying it can help reduce cold and flu risk as well. The CDC mandates that anyone who uses public transportation or flies commercial must wear a mask too, regardless of transmission rates. 

Many of these lingering mandates were snapped back into place amid rising cases over the summer, after vaccines first became available. But as cases start to plateau – and experts say COVID-19 may be here to stay at a certain level – many are questioning whether it's time to get rid of such measures lest the U.S. never return to normal. 

"We may have a baseline rate of COVID cases hovering around where they are now in the Southeast forever," Johns Hopkins Professor Marty Makary said in an interview this week. "We are entering an endemic phase and the question we need to ask as a society is, do we want a perpetual society with people masked?"

Dr. Marty Makary speaks during a screening of the HBO documentary film

Dr. Marty Makary speaks during a screening of the HBO documentary film 'Bleed Out' on December 12, 2018 in New York City. Makary is a Fox News contributor. (Noam Galai/Getty Images for HBO)

Makary added: "And the marginal benefit of masking is diminishing as the prevalence declines. Also, in many instances we're requiring masks of people at the absolute lowest risk and by insisting on throwing the kitchen sink at virus transmission we will have to pay the piper somehow. That may come in the form of a loss of human connection, more increased mental health problems, and in children a series of problems including issues in development and speech development and other downsides."

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Makary said that he is not, in principle, opposed to mask mandates when they are necessary. But for public health officials to "maintain credibility," he said, "we have to remove public health restrictions as aggressively as we put them in place."

But many governments with mask mandates still don't appear to have a plan for when or how to roll back their rules. 

"We know there is still much to be done to stop the spread of COVID-19 and end the pandemic. We are still seeing far too many new cases, hospitalizations, and deaths," CDC spokesperson Jade Fulce said in response to a query from Fox News. 

"As we look forward to the fall and winter, it’s important to continue practicing prevention measures that we know work – vaccinating, wearing a mask in public, indoor settings, staying home when you are sick, and washing your hands frequently."

In this stock photo, students are masked in a classroom. It's not clear when some governments plan to lift their COVID-19 virus rules, including mask mandates. 

In this stock photo, students are masked in a classroom. It's not clear when some governments plan to lift their COVID-19 virus rules, including mask mandates.  (istock)

Fulce did not respond to a follow-up question asking whether the CDC has any specific goals, metrics or benchmarks in mind that would cause it to loosen virus rules. 

Spokespeople for the health departments and governor's offices in Oregon and Washington did not respond to requests for comment asking about their plans. Neither did a spokesperson for Washington, D.C. 

Fox News also asked those governments, as well the CDC, Illinois and Los Angeles, whether they are concerned about the "downsides" of masking mentioned by Makary, and if non-COVID diseases like the cold or flu are factoring into their decisions on masks. None answered those questions. 

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Illinois Department of Public Health spokesperson Melaney Arnold instead said the state is open to lifting its mask mandate if virus numbers "stabilize," but warned of possible case spikes over the holidays. 

"The largest wave over the course of the pandemic began in October of last year – when people started spending more time indoors because of the weather and getting together with friends and family for the holidays," Arnold said. "We want to do everything possible to make sure that doesn’t happen again this year."

"If data shows things might be stabilizing, we can look at lifting the requirement to wear a mask – something that adds a layer of protection on top of vaccination," she added. "The entire purpose of masking is to protect people, not penalize them. The last thing any of us want is to see another surge so we are being cautious in how we move forward. We will continue to evaluate trends, and based on what we see, we will look at lifting masking requirements."

Illinois Gov. J.B. Pritzker attends a fundraiser on April 12, 2018 in Chicago, Illinois, while still a candidate. Illinois said that is may lift mask rules if COVID-19 cases stabilize, but did not present a specific framework by which it is making that decision. 

Illinois Gov. J.B. Pritzker attends a fundraiser on April 12, 2018 in Chicago, Illinois, while still a candidate. Illinois said that is may lift mask rules if COVID-19 cases stabilize, but did not present a specific framework by which it is making that decision.  (Scott Olson/Getty Images)

Of the governments contacted by Fox News for this story, only Los Angeles County presented a specific framework for when mask mandates might be lifted. But the standards for the lifting of mask rules are very high, and even then pandemic rules will still be in place through vaccine mandates in public places. 

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For mandates to be lifted at large events in Los Angeles County, case rates will need to decline to less than 50 per 100,000 for three straight weeks, hospitalizations must drop to "below 600 daily" and remain stable for three straight weeks, 80% of residents over 12 must be vaccinated and there can't be "significantly circulating new variants of concern." This is according to a guidance released last week. 

The rules for removing mask rules at smaller indoor settings like offices and retail sites are more strict. All of the above metrics must be met, and there must be a full "vaccine verification process in place, and all employees and customers must be fully vaccinated." 

Not all localities are so strict. Montgomery County, Maryland, recently lifted its indoor mask mandate. So did Atlanta. 

But with so many major cities and states – and even the federal government – appearing to have no plan to roll back their pandemic rules, it's unclear when the burdensome mandates will stop affecting many Americans' everyday lives. 

"You can't cry wolf too many times," Makary said, or the next time there's a public health threat people may not "respond appropriately."