Este artículo estará disponible en español en El Tiempo Latino.
The chair of Robert F. Kennedy Jr.’s newly constituted vaccine advisory committee announced in his first meeting that the panel will revisit the longstanding practice of vaccinating all babies against hepatitis B, questioning whether it was “wise” to administer shots “to every newborn before leaving the hospital.” Experts, however, say there are valid reasons to vaccinate babies against hepatitis B, and that it has proven to be safe and very effective.
“It’s virtually eliminated hepatitis B acquisition during childhood,” one infectious disease expert told us.
Martin Kulldorff, the chair and one of seven new members of the Centers for Disease Control and Prevention’s Advisory Committee on Immunization Practices, is a former Harvard Medical School professor who became known for opposing various public health measures during the COVID-19 pandemic. ACIP has for more than 60 years advised the agency on who should get which Food and Drug Administration-approved vaccines, how often and when.
Earlier this month, Kennedy, the Health and Human Services secretary, removed all 17 existing members of the panel, alleging conflicts of interest issues and inadequate scrutiny of vaccines. As we’ve written, there isn’t evidence for those claims. Kennedy is a longtime anti-vaccine advocate.
Two days after dismissing the committee, Kennedy announced eight new members, including several with a history of spreading false and misleading information about vaccines and others with little or no expertise in vaccines. (The night before the group’s first meeting, HHS told the New York Times that one of the named panelists decided to withdraw “during the financial holdings review.”) Some remaining panelists have past ties to vaccine-related litigation, including Kulldorff, who served as an expert witness for plaintiffs alleging harm from HPV vaccination.
Near the beginning of the group’s first meeting, Kulldorff announced that two new work groups, or ACIP subgroups, would be formed: one that will look at the “cumulative effect” of the childhood and adolescent vaccination schedules, and another that would look at vaccines that have not been reviewed “in more than seven years.”
The latter work group, Kuldorff suggested, would revisit hepatitis B vaccination, which has been recommended for babies since 1991.
“Among other topics, this new vaccine group may look at the universally recommended hepatitis B vaccine at the day of birth,” Kulldorff said. “Is it wise to administer a birth dose of hepatitis B vaccine to every newborn before leaving the hospital? That’s the question. Unless the mother is hepatitis B positive, an argument could be made to delay the vaccine for this infection, which is primarily spread by sexual activity and intravenous drug use.”
It’s true that sex and intravenous drug use are major transmission pathways for hepatitis B in adults. But as we’ve explained before, when Kennedy similarly questioned why newborns would need to be vaccinated, infected mothers can spread the virus to babies during birth and infants or older children can pick up the virus from caregivers who may not even know they are infected.
While pregnant mothers are usually tested for HBV, results can be delayed or incorrect. As a result, vaccinating all infants at birth “acts as a safety net,” an archived CDC FAQ explains. Starting the vaccine series at birth also increases the chance that a child will complete the three-shot series. Claims appealing to the youth of babies and pointing to adult risk factors are common techniques used by activists to argue against hepatitis B vaccination.
Preventing infection in childhood is particularly important, since babies and young children are far more likely than adults to be unable to clear the virus from their bodies and develop a chronic hepatitis B infection. These infections can cause serious problems, such as liver cancer or liver failure.
Kulldorff’s line of inquiry also ignores the history of hepatitis B vaccination in the U.S.
When the vaccine was first approved in the 1980s, the U.S. tried a risk-based vaccination approach that included infants born to mothers with the virus.
“It didn’t work,” Dr. William Schaffner, a professor of infectious diseases at the Vanderbilt University Medical Center, told us.
It was only after 1991, when the U.S. switched to a universal recommendation, that hepatitis B infections in children began to dramatically decline.
“The safety and impact of the birth dose of hepatitis B vaccine has been well studied, is well established, and is very, very effective,” Schaffner said. “It’s virtually eliminated hepatitis B acquisition during childhood.”
Dr. Paul A. Offit, a vaccine expert at the Children’s Hospital of Philadelphia, told us that in 1991, there were about 18,000 cases of hepatitis B diagnosed in children below the age of 10 every year. About half of those cases were in babies infected by their mothers. The other half, he said, were infected through “relatively casual contact.”
In 2018, following recommendations from ACIP, the CDC changed its guidance to say that infants should be vaccinated within 24 hours of birth, rather than being vaccinated “preferably” before hospital discharge and no later than 2 months of age. While Kulldorff suggested there might be an advantage to waiting, there is no safety reason to delay the dose. The 24-hour recommendation is what the World Health Organization advises.
“Hepatitis B can be passed from parent to baby at birth – and when that happens, the consequences can be deadly. It is unscientific and dangerous to intentionally ignore the success of U.S. vaccination programs or argue that the U.S. should not vaccinate babies for hepatitis B at birth,” the American Academy of Pediatrics said in a post on social media shortly after Kulldorff’s remarks.
The group announced in a video earlier in the day that following Kennedy’s disbanding of the former ACIP members, the panel’s immunization policy setting “is no longer a credible process,” and that AAP would continue to issue its own vaccine recommendations, now separately from ACIP.
It’s worth noting that while Kulldorff said the work group would look at vaccines that haven’t been reviewed in the past seven years, ACIP has discussed the hepatitis B vaccine as recently as 2024, although those recommendations were specific to adults. The 2018 pediatric recommendation is also barely more than seven years old.
Dorit Reiss, a vaccine law expert at University of California Law San Francisco, told us that the latest discussions have been about adults “because there has not been new evidence about babies,” adding that ACIP reviews vaccines on a rolling basis but generally “does not go in depth without new questions or new data.”
As for the idea that the cumulative effects of multiple vaccines have not been sufficiently studied, that has also long been used to raise doubts about vaccine safety. Citing the number of vaccinations American children receive, Kulldorff announced a new work group to look at “the cumulative effect of the recommended vaccine schedule,” including “interaction effects between different vaccines, the total number of vaccines, cumulative amounts of vaccine ingredients, and the relative timing of different vaccines.”
But new vaccines are routinely studied in the context of the standard vaccine schedule, and the safety of the childhood vaccine schedule is well-established. Although often cast as a negative, the addition of more vaccines over time means children today are protected against more diseases than their grandparents or even parents were.
“The basic, frequent immunization of infants has been studied up, down and around” in countries around the world, Schaffner told us.
Offit explained that a new vaccine undergoes a large, randomized controlled trial to determine whether it is safe and effective. These trials are by definition looking at the cumulative impact of vaccination, since participants will also have received age-appropriate, standard vaccines.
Before adding a new safe and effective vaccine to the schedule, Offit said, it’s then required to test whether giving it at the same time as other vaccines interferes with safety or the body’s immune response to one or more of the vaccines. The results of these studies help determine which vaccines are given together at the same appointment.
It is “a well-hewn schedule,” Offit said. “It’s built on a mountain of scientific evidence.”
Offit questioned what sort of further study would be feasible to understand the cumulative effects of the vaccine schedule. “Would you just take children who got all the vaccines and compare them to children who got some of the vaccines and see whether or not they did better if they only got a few of the vaccines?” he said. “I don’t see how you would do that.”
One common concern that is not borne out by the evidence is that getting a large number of vaccines relatively quickly might have some negative effect on a child’s immune system. This misunderstands how the immune system works. Children are exposed to far more immune challenges in everyday life from viruses and bacteria than they ever receive from vaccines. And Offit said that vaccines today each have fewer antigens, or microbial components used to produce an immune response, than vaccines of the past.
“I would argue you had a greater immunological challenge from the one vaccine we got 100 years ago than the 14 different vaccines to prevent 14 different diseases that we give to children today,” Offit said.
Editor’s note: FactCheck.org does not accept advertising. We rely on grants and individual donations from people like you. Please consider a donation. Credit card donations may be made through our “Donate” page. If you prefer to give by check, send to: FactCheck.org, Annenberg Public Policy Center, P.O. Box 58100, Philadelphia, PA 19102.