An internal presentation circulated at the Centers for Disease Control and Prevention last month and eventually obtained by news organizations provided clear advice on how to control the contagious Delta variant: “With greater portability and updated vaccine coverage, universal masking is essential . “

Much more nuanced, however, was the agency’s recommendation, which advised vaccinated or unvaccinated Americans to wear masks in indoor public spaces in areas with “significant” or “high” virus transmission.

Back then, that was at least 80 percent of Americans. In view of the increasing infection rates, some experts are now asking themselves: Would it have made more sense to just ask everyone to mask?

“With rates rising across the country, the clearer message would be, ‘Wear a mask in public indoor spaces anywhere in the country,'” said David Michaels, professor of environmental and occupational medicine at the Milken Institute of Public Health at George-Washington -University.

In addition to Americans in Covid-19 hotspots, CDC officials also recommended universal indoor masking for teachers, staff, students, and school visitors, regardless of where they are and regardless of individual vaccination status.

And the agency suggested that if they or someone in their household is immunocompromised or at risk for a serious illness – or unvaccinated, a category that all children under – “regardless of the degree of transmission, people could opt to be masked” 12 years of age who do so do not qualify for vaccination.

Also on the list: people who are overweight, smoke or have a disability, as well as anyone who has had close contact with someone with confirmed or suspected Covid-19. That’s a lot of Americans.

“The messages from the CDC were not optimal,” said Dr. Ezekiel Emanuel, vice president of global initiatives at the University of Pennsylvania. “We have to be clear and relatively simple.”

Masking advice from federal health officials has changed during the pandemic. In February 2020, Americans were told not to buy masks that were in short supply. In April 2020, officials recommended that masks be worn outside the home. In May of this year, the CDC announced that vaccinated people would no longer have to wear masks.

Agency officials did not respond to requests for comment on the latest revised recommendations. But the director of the agency, Dr. Rochelle Walensky said she was forced by early data suggesting the delta variant changed the equation and that vaccinated people could spread the virus on the rare occasions when they were affected.

Significant evidence emerged from an outbreak in Provincetown, Massachusetts, on the weekend of July 4th. Almost a thousand people were infected, most of them fully vaccinated.

But many Americans have no idea week after week whether they live in a community with significant or high transmission of the virus.

Updated

Aug 16, 2021, 9:29 p.m. ET

The definitions are not easy to understand: Significant or high transmission means any community that has had at least 50 new infections per 100,000 population in the past seven days, or at least 8 percent of tests positive for an infection during that period. (The agency keeps a card.)

A simpler mask recommendation probably wouldn’t have paved the way for mandates in a state like Texas, where two state judges this week allowed officials in Dallas County and Bexar Counties, which include San Antonio, to impose mask requirements on them from the governor despite an executive ban Greg Abbott.

In many municipalities mandates are gaining in importance, and the nuances about transfer rates and framework conditions have already been left aside. The reason is easy to see: the virus has been spreading rapidly in 90 percent of US counties since Tuesday. And the masking takes effect quickly.

Masks “are actually amazing because they work instantly – they’re starting to reduce transmission today,” said Julia Raifman, assistant professor at Boston University’s School of Public Health. “Every case they prevent prevents several other cases, so their effectiveness grows over time.”

Understand the state of vaccination and masking requirements in the United States

    • Mask rules. The Centers for Disease Control and Prevention in July recommended that all Americans, regardless of vaccination status, wear masks in public places indoors in areas with outbreaks, reversing the guidelines offered in May. See where the CDC guidelines would apply and where states have implemented their own mask guidelines. The battle over masks is controversial in some states, with some local leaders defying state bans.
    • Vaccination regulations. . . and B.Factories. Private companies are increasingly demanding coronavirus vaccines for employees with different approaches. Such mandates are legally permissible and have been confirmed in legal challenges.
    • College and Universities. More than 400 colleges and universities require a vaccination against Covid-19. Almost all of them are in states that voted for President Biden.
    • schools. On August 11, California announced that teachers and staff at both public and private schools would have to get vaccinated or have regular tests, the first state in the nation to do so. A survey published in August found that many American parents of school-age children are against mandatory vaccines for students but are more likely to support masking requirements for students, teachers and staff who are not vaccinated.
    • Hospitals and medical centers. Many hospitals and large health systems require their employees to have a Covid-19 vaccine, due to rising case numbers due to the Delta variant and persistently low vaccination rates in their communities, even within their workforce.
    • new York. On August 3, New York City Mayor Bill de Blasio announced that workers and customers would be required to provide proof of vaccination when dining indoors, gyms, performances, and other indoor situations. City hospital staff must also be vaccinated or have weekly tests. Similar rules apply to employees in New York State.
    • At the federal level. The Pentagon announced that it would make coronavirus vaccinations compulsory for the country’s 1.3 million active soldiers “by mid-September at the latest. President Biden announced that all civil federal employees would need to be vaccinated against the coronavirus or undergo regular tests, social distancing, mask requirements and travel restrictions.

Wearing a mask also helps protect children who cannot yet be vaccinated and others who are vulnerable, such as the elderly and people with weakened immune systems who may not be able to build a strong immune response after vaccination.

The masking also helps prevent the virus from circulating, reducing the chance it will mutate, possibly into a more virulent form that vaccines may bypass completely.

“If you allow the virus to circulate freely and don’t try to stop it, sooner or later there is a chance you’ll get another variant that could, I’m not saying it will, but it could be more problematic than that the delta. “Dr. Anthony Fauci, the nation’s leading infectious disease expert, said on NBC’s “Meet the Press” Sunday.

The CDC noted that blacks, Hispanics and Native Americans are at higher risk for Covid-19, but said nothing more about minority communities taking masking measures.

A universal masking recommendation might have helped protect communities at risk, including communities of color where vaccination rates have lagged partly due to distrust of the medical system and partly due to persistent problems with accessing health care, said Dr. Rhea Boyd, a pediatrician, studies the relationship between structural racism and health.

“If you live in an area where many people are not vaccinated, you are often exposed to the virus,” said Dr. Boyd.

Still, some experts understand the fine line the CDC has to walk in making recommendations for change – especially in masking, which has become a cultural and political hotspot.

Mask requirements can threaten the livelihood of restaurants, bars, and other indoor settings that serve food. In Louisiana, Governor John Bel Edwards temporarily reintroduced a nationwide mandate for interior masks earlier this month amid a surge in cases. But he made an exception for “anyone who has a drink or meal”.

By defining localized benchmarks, the agency’s mask recommendation gives “everyone something to look forward to,” said Dr. Carlos del Rio, an infectious disease specialist at Emory University School of Medicine in Atlanta. “Ultimately, the CDC is a science agency that responds to politicians.”

Even so, he added, “You should wear a mask when you are inside.”