A CDC panel of experts changed some of their guidance on COVID-19 vaccines on Friday, a day after changing their recommendations around the measles, mumps, rubella and varicella (MMRV) vaccine for kids.

The Friday vote takes a step back on recommending the COVID-19 shot. Rather than recommending it outright for most adults as the panel has in the past, it voted that it should be available to everyone, and people should make a personal decision about whether or not to get it alongside their doctor.

It also recommended advising patients on more potential risks associated with COVID-19 shots and narrowly avoided urging states to require a prescription for the shot.

The Advisory Committee on Immunization Practices was also considering a change regarding the hepatitis B vaccine for newborn babies, but that decision was shelved indefinitely during the meeting, which at times veered into chaos and argumentation between members.

The panel was hand-selected by Health and Human Services Secretary Robert F. Kennedy Jr., who ousted all of the advisory panel’s previous 17 members.

He appointed eight new experts to the panel days later, and then added another five this week — many of whom have been skeptical of vaccine safety and accused of spreading misinformation.

Data from the U.S. Centers for Disease Control and Prevention (CDC) shows that COVID-19 vaccines provide the strongest protection against severe infection and death, even if people still become infected. A number of concerned doctors and members of the public weighed in with concerns regarding the evidence the panel heard, which questioned the safety of the vaccines.

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Following Friday’s meeting, the president of the American Pediatric Association (AAP) warned that the panellists’ comments and questions showed a lack of knowledge about vaccines.

“What we’re seeing is what happens when individuals who don’t have a basic understanding about how vaccines are delivered are making these crucial policy decisions for the American public. They don’t know what they’re doing,” said Sean T. O’Leary of the AAP.

He also said lots of questions remain about who will have access to these vaccines, because “what we are getting from this [panel] is confusion.”

The group’s job is to advise the CDC on U.S. vaccination schedules. As the top health body in the country, doctors look to the CDC on how to advise their own patients, and many insurers make decisions about what vaccines they’ll pay for based on CDC recommendations.

MMRV change, postpone vote on hepatitis B

The committee voted Thursday to recommend against allowing parents to choose a combined MMRV vaccine for children under the age of four. Instead, they recommend the use of a combined measles-mumps-rubella shot and a separate one for varicella (also known as chickenpox).

The combined MMRV shot was previously an option for children 12 months of age or older, though the CDC already recommends that separate MMR and varicella vaccines be given under age 4 unless parents express a preference for the combined shot.

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The panel made their decision based on the risk of febrile seizures (a convulsion caused by a fever), which occasionally occur in kids after they’ve been given the first dose of the combined vaccine, though it is rare.

According to the CDC’s own data, these seizures only occur in eight kids per 10,000 who get the combined MMRV shot. There’s also a very small risk of febrile seizures with the split MMR and chickenpox vaccines — about 4 in 10,000.

These seizures can also occur when children have a fever due to an illness — including from infection with diseases like chickenpox or measles — and also don’t usually cause long-term harm.

In the wake of the vote, the American Academy of Pediatrics (AAP) said the CDC’s meeting promoted “misguided information” about childhood vaccines, adding that their organization still views both vaccines as safe.

While the CDC is still recommending that people get vaccinated against all four of the infectious diseases, University of Saskatchewan virologist Angela Rasmussen says the decision will require parents to book additional vaccine appointments and have their kids sit through more shots. That added layer of difficulty might mean some kids simply don’t get vaccinated against the full slate of illnesses, she said.

She says vaccine uptake in the U.S. has already been declining, and that an added layer of difficulty will mean more kids will go unvaccinated and end up getting sick.

“Adding another mechanism … for reducing vaccine uptake is going to have huge consequences in terms of measles epidemics that have happened recently, and in fact are ongoing,” Rasmussen said.

The panel was also expected to vote on delaying the first hepatitis B shot until at least one month of age in infants born to mothers who test negative for the virus. That vote was postponed until Friday morning and then pushed off again indefinitely.

The group did, however, vote in favour of testing all pregnant women for hepatitis B.

Ahead of the hepatitis B vote, medical experts and patient advocates feared delaying giving the shot would leave infants vulnerable to infection, which can cause liver failure and liver cancer later in life.

What does this mean for Canadians?

None of the CDC votes directly affects Canadians or the recommended use of either of those vaccines north of the border.

In Canada, the National Advisory Committee on Immunization (NACI) recommends either the combined MMRV vaccine or the MMR shot and separate varicella vaccination at 12 to 15 months of age, and a second dose at 18 months or sometime before the child starts school.

But Canada also buys a lot of vaccines from the U.S., according to Dr. Donald Vinh, an infectious disease specialist at the McGill University Health Center. If changes to the CDC’s recommendations lead to less demand for the MMRV shot, it could mean less production from U.S. makers — which could affect Canadian supply.

“We’re not talking about just the medical decision, but also the logistics,” Vinh said.

Plus, viruses and vaccine misinformation alike can’t be contained by borders, Rasmussen says. She points out that due to skepticism about the MMR and MMRV vaccines, rates of vaccination against those diseases have been dropping within Canada already.

“If people begin importing these preventable diseases [when travelling], and the vaccination rates get low enough in Canada, we’ll start seeing outbreaks of those pathogens as well,” Rasmussen explained. “Where the U.S. goes, many other countries follow.”

Canada and other nations worldwide will be impacted by the loss of good health expertise, as the CDC has historically played a leading role in vaccine research and policy. Lynora Saxinger, an infectious diseases physician, says she used to tune into these ACIP meetings to hear their evidence because the CDC was a guiding health body.

But now, “most people that I know in my field … would no longer regard decisions coming from the CDC as being robust decisions,” Saxinger said.

Because the CDC has been a source of good information in the past, Saxinger says the risk is twofold: People who don’t know about the changes to the CDC’s leadership could wind up being misinformed by future information they put out, she says, while vaccine skeptics could point to these decisions as evidence.

Vaccine skeptics on the panel

Under Kennedy’s leadership, the committee has undergone a dramatic transformation in recent months.

In early June, Kennedy ousted all of the advisory panel’s 17 members. He appointed eight new experts to the panel days later, and then added another five this week. While some of them had served on CDC or FDA committees before, many have previously been skeptical of infectious disease spread, vaccines, or both.

One of the appointees, Retsef Levi, has previously cast doubt on the safety of mRNA vaccines, saying they can cause serious harm and death, especially among children, according to Reuters.

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Martin Kulldorff, another of RFK’s picks and chair of the committee, was also an architect of the Great Barrington Declaration — a document published in October 2020 that advocated against COVID-19 lockdowns. He co-founded a journal that has raised speculation among scientists and health experts who worry it might become home to dubious information, and was also fired from Harvard University in 2024 when he refused to get vaccinated.

On Thursday, Kulldorff defended the credibility of those on the panel and called himself the most “pro-vaccine scientist in the country.” He also said his opponents should be willing to test their science in a debate — which he said he’d be willing to have publicly with past CDC directors.

“The members of this … committee are committed to reassuring the public and restoring public confidence [in vaccines] by removing unnecessary risk and harms whenever possible. That is a pro-vaccine agenda,” he said.

“False accusations that we … are unscientific and dangerous antivaxxers, that just adds legitimacy to anti-vax positions, damaging both public health and the confidence in vaccines.”