Advice from federal health officials that fully vaccinated people could drop their masks in most settings came as a surprise to Americans, from government officials to scientific experts. Even the White House received less than a day’s notice from the Centers for Disease Control and Prevention, press secretary Jen Psaki said at a news briefing Friday.
“The CDC, the doctors and medical experts there, are the ones who decided what this guide would be based on their own data and what the timeline would be,” Ms Psaki said. “It was not a decision led or taken by the White House.”
For months, federal officials have strongly warned that wearing masks and social distances was necessary to curb the pandemic. So what changed?
Introducing the new recommendations Thursday, Dr. Rochelle P. Walensky, CDC director, cites two recent scientific findings as significant factors: Few vaccinated people become infected with the virus, and transmission seems increasingly rare; and the vaccines appear to be effective against all known variants of coronavirus.
There is no doubt at this point that the vaccines are strong. On Friday, the CDC released results from another large study that showed that the vaccines from Pfizer-BioNTech and Moderna are 94 percent effective in preventing symptomatic disease in those who were fully vaccinated, and 82 percent effective even in those who only partially vaccinated.
“Science is well aware of this,” said Zoë McLaren, a health policy expert at the University of Maryland, Baltimore County. Evidence is showing that it is very unlikely that people who have been vaccinated will catch or transmit the virus, she noted.
The risk “is certainly not zero, but it is clear that it is very low,” she said.
One of the persistent concerns among researchers had been that even a vaccinated person might be able to carry the virus – perhaps briefly without symptoms – and spread it to others. But CDC research, including the new study, has consistently found few infections among those who received the Pfizer-BioNTech and Moderna vaccines.
“This study, added to the many studies that preceded it, was crucial to the CDC changing its recommendations to those who are fully vaccinated against Covid-19,” said Dr. Walensky in a statement Friday.
Other recent studies confirm that people infected after vaccination carry too little virus to infect others, said Florian Krammer, a virologist at the Icahn School of Medicine at Mount Sinai.
“It’s really hard to even sequence the virus sometimes because there is very little virus and it is there for a short period of time,” he said.
Still, most of the data has been collected on the Pfizer-BioNTech and Moderna vaccines, warned Dr. Cuddling. Because Johnson & Johnson’s vaccine was approved later, there are fewer studies evaluating its effectiveness.
In clinical trials, the Johnson & Johnson vaccine was 72 percent effective – lower than the Pfizer and Moderna vaccines. And the effectiveness was measured in terms of moderate and severe illness rather than mild illness.
“It is a very good vaccine and I am sure it will save many, many, many lives,” said Dr. Cuddling. “But we need more data on how well J. & J. vaccine prevents infection and how well it prevents transmission. ”
Variants of the virus have been a particular concern for researchers. Mens Dr. Walensky cited evidence showing that mRNA vaccines such as those from Pfizer and Moderna are effective against the variants circulating in the United States, there is little data on variants and the Johnson & Johnson vaccine. And new varieties are constantly emerging.
“I am not saying at all that this is now a big problem,” said Dr. Cuddling. But before I lifted the masking requirements, “I may have waited a little longer to look at the numbers.”
In a statement on Friday, a spokesman for the CDC said, “All of the approved vaccines provide strong protection against serious illness, hospitalization and death, and we are collecting data that our approved vaccines are effective against the variants circulating in this country. . ”
Fully immunized people are unlikely to become seriously ill even if they are infected with coronavirus. The risk of infection is greater for the people around them – unvaccinated children and adults or vaccinated people who remain unprotected due to a medical condition or treatment.
CDC officials said they weighed these factors and were confident in their assessment of the science. And the new counseling has other happiness effects that reward fully immunized people by allowing them to end their social isolation – and perhaps encourage others to choose vaccination.
The new council “signals that we are really on the last stretch here and I think that is a very good thing for people,” said Dr. Joshua Sharfstein, Vice Dean of Public Health Practice and Community Engagement at Johns Hopkins University Bloomberg School of Health.
“It is unlikely that we will get another huge increase in cases,” he added. “But will the last stretch last for weeks or months is still an issue.”
The difficulty with the new recommendations, he and other experts said, is not so much the science that supports them as their implementation.
Leaders at the state, city, and county levels still have the authority to demand masks, even for vaccinated people, as the CDC quickly recognized Thursday. Following the agency’s announcement, some states immediately lifted mask mandates, while others said they would need more time to weigh the evidence.
But in states without mask mandates, the obligation to check vaccination status will fall on store owners, restaurant workers, school administrators and workplace managers.
“Without a means to verify vaccination, we will have to rely on a system of honor,” said Caitlin Rivers, an epidemiologist at Johns Hopkins University.
The number of cases in the country is the lowest it has been since September, and many experts support mandates for lifting masks in large parts of the country. But doing so will be more risky in places like Michigan, where there are more cases, and for people who are unprotected, including children under the age of 12 and people with a weak immune system, said Dr. Rivers.
“People who are not vaccinated should continue to wear masks in public indoors and avoid crowds,” she said.
In Nacogdoches, Texas, Dr. Ahammed Hashim complained that only 36 percent of the population was immunized and that the pace seemed to have stalled. And yet only one or two people out of 10 in the local shops had masks.
“I think the CDC may be sending the wrong message saying everything is fine,” said Dr. Hashim, a pulmonologist. “It would feel much better if we had a vaccination of 60 or 70 percent.”
The CDC’s guidelines are intended for fully vaccinated individuals and should only be interpreted as such, warned Dr. Sharfstein. Nationwide, only 36 percent of the population is fully vaccinated.
“What we are just seeing is a little bit of the distance between counseling that is perfectly appropriate for people who have been vaccinated and the reality that there are places that still see viral transmission and many people who have not been vaccinated,” he said.
Individuals can make choices based on their perception of their own risks, but state and local leaders must decide what is best for society based on the number of infections. “These are two different things,” said Dr. Sharfstein. “And when they get merged, that’s when people can make bad judgments about politics.”
The new guidelines should serve as a reminder to health officials to intensify their outreach and investment to ensure everyone has access to vaccines, Drs. McLaren. Parents of children under the age of 12 should continue to encourage them to wear masks indoors.
The CDC’s new policy also shifts the obligation to immunocompromised people to protect themselves against unmasked and unvaccinated people.
“When we make policy, we have to balance everyone’s needs and wants,” said Dr. McLaren. “We could go on masking forever, but there are benefits to returning to a life that looks more normal.”
Health officials should stress that the situation may yet change, and official recommendations with it she added: “We really need to practice being good at responding to changing situations.”