As for quarantine, people who have received booster doses of vaccine are advised that they may safely stay out and about, even if exposed to the virus, if they wear masks for 10 days, and even the unvaccinated may leave quarantine after five days.

In the past, and under previous pandemic plans, such a big change in recommendations would have first been run by expert groups such as NACCHO for input. And they would have been carefully explained in the media.

“Having made this mistake — I am speaking as someone who has learned over the years — this is one of the things where you hold a news conference and you sit down and explain every aspect of it,” said Dr. Georges Benjamin, executive director of the American Public Health Association.

“You explain your decision-making process,” Benjamin told CNN. “So you say, ‘we are concerned that people can’t get back to work, that we have health care workers sitting around who are not really a big threat to patients,’ ” Benjamin added.

Gigi Gronvall, a senior scholar at the Johns Hopkins Center for Health Security, agreed: “For flu, sometimes like when we were concerned about pandemic flu, there were expert meetings or calls … before they were rolled out.”

State and local health officials are often on the front line of communication about new policies, and they got no warning or preparation for the latest update, Freeman said. The CDC did not provide posters, charts or visual aids, or any of the background that might help communicate the new advice to the public.

Instead, CDC Director Dr. Rochelle Walensky and Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, have been defending and explaining the change in television and newspaper interviews this week.

Both have said, without offering data as evidence, that people are unlikely to transmit the infection after about five days from onset of symptoms.

“The thing about the guidance change for the general population is, the science and the data hasn’t come up,” Freeman said.

“We are in the unenviable position of having to explain,” she added.

“I asked the CDC to clarify when they have to make these decisions outside the use of science and evidence so everybody understands that sometimes, this has to take place so that people don’t just think it is politics.”

Dr. Marcus Plescia, chief medical officer at the Association of State and Territorial Health Officials (ASTHO), said his group’s members are irritated and disappointed.

“Every time CDC does a call to try to clarify something, people seem to become more confused,” he told CNN.

Many questions have been left unanswered, such as how the advice might apply to schools or people in congregate settings such as nursing homes or prisons.

“This is very atypical CDC, to come out with stuff that is incomplete,” Plescia said.

Had the CDC briefed groups such as ASTHO and NACCHO first, the experts there could have pointed out confusing parts of the new advice and helped strengthen it, say the public health experts CNN spoke with.

Skeptics already suspicious of the public health establishment otherwise have even more fodder for accusations that everything was just made up, Freeman said.

“We need to avoid this looking like random decisions,” she said.

“This is welcome news in some respects; that’s the sad part of this,” Freeman added. “If it had been messaged a little bit differently, it might give people hope.”

Gronvall agreed. “Messaging — that was where things definitely broke down,” she said. “I read the guidance, and it seems reasonable.”

Plescia said the guidelines make sense. “I think the guidelines are responsive to the situation we are in. They are attempting to stick to science. But they are also trying to deal with the reality of the situation.

“I think it’s too bad it has been so confusing rolling it out.”

Gronvall said the lack of clarity from CDC encouraged critics to attack the guidelines.

“The simpler the message, the easier it will be for people to comply,” Benjamin said.

David Holtgrave, dean of the School of Public Health at the University at Albany, State University of New York, disagrees that the guidance is reasonable.

He wishes the CDC had stressed the use of testing before people release themselves from isolation and quarantine.

“Allowing someone with ‘resolving’ symptoms to simply exit isolation without a negative test is not supported by any public health science or best practice of which I am aware,” Holtgrave told CNN.

He fears that it could undermine “test-to-return” to school policies.

“With CDC’s new guidance, someone might easily want to say that they have not tested positive in the last five days, are without fever or symptoms, and therefore there is no need for a screening test,” he said.