New CDC advisers scale back recommendations on MMRV vaccine in young kids

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The Centers for Disease Control and Prevention (CDC) vaccine advisory group today changed its recommendations for the measles, mumps, rubella, and varicella (MMRV) vaccine for the youngest children, continuing efforts by Health and Human Services (HHS) Secretary Robert F. Kennedy Jr. to shake up childhood vaccine policies and schedules.

Varicella is also known as chickenpox. A scheduled vote on use of the hepatitis B vaccine at birth was tabled until tomorrow.

Deliberations in highly charged setting

Skepticism of childhood vaccines, along with the numbers of them that American children receive, has been one of Kennedy’s main issues over many decades. And since his confirmation as HHS secretary in February he has taken steps to challenge established guidelines, partly through his hand-picked 12-member Advisory Committee on Immunization Practices (ACIP) panel, many of whom share his views.

Without evidence, he has unilaterally changed the CDC’s COVID recommendations for children and other groups and has signaled sweeping changes to the childhood vaccine schedule, a point that was underscored yesterday at a hearing before the Senate HELP (Health, Education, Labor & Pensions) Committee to probe the recent firing of CDC director Susan Monarez, PhD. She told lawmakers she was fired after refusing to pre-approve ACIP recommendations, regardless of scientific evidence.

When asked about the potential fallout from the Kennedy-led vaccine changes, Monarez told senators yesterday that she worried that diseases like measles, polio, diphtheria, and whooping cough will return. "I believe our children will be harmed by things they do not need to be harmed by," she said.

I believe our children will be harmed by things they do not need to be harmed by.

Susan Monarez, PhD, former CDC director

In an opening statement, ACIP Chair Martin Kulldorff, PhD, a statistician and epidemiologist formerly at Harvard University, lashed out at recent critics of the vaccine panel and federal policy changes. He singled out a group of former CDC directors who published an editorial 2 weeks ago that raised concerns about Kennedy’s recent vaccine policies and related staff upheaval at the CDC as well as the American Academy of Pediatrics (AAP), one of the groups that has issued its own vaccine recommendations and as one of several ex officio members is boycotting the ACIP meetings.

“With such debates, you can weigh and determine the scientific reasoning by each side, but without it, you cannot properly judge their arguments,” he said.

The new developments come as states and medical organizations depart from CDC recommendations and as the nation’s biggest insurance company trade group has signaled that it, at least for COVID and flu vaccines, will continue to provide coverage based on the recommendations of top medical organization.

MMRV vote raises access issues

On the MMRV vote, the committee removed a long-standing ACIP recommendation, which stated that separate measles, mumps, and rubella (MMR) and varicella vaccination be used for children 12 to 47 months old, but that parents have the option of the MMRV vaccine for that age-group. Eight ACIP members voted to stop recommending the MMRV for children before the age of 4 years, while three voted against the measure and one member abstained.

The group, however, did vote to maintain coverage for the MMRV vaccine through the Vaccines for Children program.

The MMRV vaccine was licensed in 2005 and is designed to streamline vaccine administration and boost overall vaccine uptake. The first dose of the live-attenuated vaccine is usually given from 12 to 15 months of age, with the second dose given from 4 to 6 years of age. The vaccine carries a slightly higher risk of febrile seizures when given as the first dose compared with separate MMR and varicella vaccines, especially among younger children.

Currently, only 15% of parents opt for the combined vaccine for children ages 12 to 15 months.

ACIP last discussed the MMRV vaccine in 2009, reviewing efficacy and safety data and affirming that the MMRV vaccine could deliver the two recommended doses required for protection against measles, mumps, and rubella. That recommendation emphasized that doctors should talk to parents to weigh the small seizure risk with the potential benefits of giving the two vaccines at once.

Questions about evidence for change

Today’s discussion weighed heavily on CDC expert presentations and input from its subject matter experts, but it also included anecdotal experiences and physiologic questions that are typically the purview of the Food and Drug Administration (FDA).

Some members, however, along with liaison participants, questioned whether there was enough evidence for the change. They worried about a lack of access for parents who would rather their child receive the combo shot, and wondered if the change would diminish overall vaccine uptake.

Cody Meissner, MD, who has served on both CDC and FDA vaccine advisory committees and is a professor of pediatrics at Dartmouth Geisel School of Medicine, said, “I’m not quite sure where we’re going. I think the current wording is appropriate.”

I’m not quite sure where we’re going. I think the current wording is appropriate.

ACIP member Cody Meissner, MD

Meissner pointed out that febrile seizures during illnesses are relatively common in young children and—though they are understandably alarming in families—typically resolve quickly with no long-term impacts.

Although CDC scientists presented safety data on the hepatitis B vaccine and ACIP members deliberated over whether to change the current recommendation that newborns receive the vaccine at birth, a vote on the issue was moved to tomorrow, when the group will also discuss and vote on recommendations for COVID-19 vaccines.