The Future of the HPV Vaccine Is Up in the Air

Until last week, the future of vaccination for human papillomavirus, or HPV, in the United States seemed clear.

For several years, a growing body of evidence has suggested that just a single dose of the vaccine may be as effective as two are, offering decades of protection against the virus, which is estimated to cause roughly 700,000 cases of cancer each year. More than 50 other countries have already adopted the one-dose schedule, and many experts hoped that the U.S. might follow suit this year.

The decision rests, primarily, on the deliberations of the Advisory Committee on Immunization Practices, a vaccine-advisory committee to the CDC. ACIP was initially expected to put to a vote, as early as next week, the questions of HPV-vaccine dosing and, simultaneously, whether to strengthen the recommendations that advise vaccination starting at 9 years of age. Several experts told me that they had tentatively expected both motions to pass, making HPV vaccination easier, cheaper, and quicker. The HPV vaccine is one of the most powerful vaccines ever developed: It is unusual among immunizations in that it durably prevents infection and disease at rates close to 100 percent. If it was deployed more widely, “we could see the end of cervical cancer,” Kirthini Muralidharan, a global-health expert and HPV-vaccine researcher at the Johns Hopkins Bloomberg School of Public Health, told me.

That was before Robert F. Kennedy Jr., the nation’s health secretary, abruptly dismissed all 17 members of ACIP. Among their replacements—each apparently handpicked by Kennedy—are several researchers who have spread misinformation about vaccines or been embroiled in litigation against vaccine manufacturers; at least one of the new members has exaggerated the harms of the HPV vaccine specifically. Now the anticipated votes on the vaccine, among other immunizations, have been removed from the proposed agenda for ACIP’s coming meeting, leaving the fate of the vaccine far murkier.

ACIP has, for decades, been one of the world’s most respected expert panels on vaccines. The group’s charter is to rigorously evaluate the evidence on the immunizations that the FDA has green-lighted. The advice it gives the CDC then helps devise the official immunization schedule that guides how insurers cover vaccines, how states mandate immunizations in schools, and how primary-care physicians advise their patients. Only under the rarest of circumstances has a CDC director rejected the committee’s advice. Effectively, the members of ACIP “decide who gets the vaccine, at what age, and how many doses,” Noel Brewer, a vaccine expert and health-behavior researcher at UNC Gillings School of Global Public Health, who served on ACIP until last week, told me.

The group’s rigorous, data-driven approach is a primary reason the HPV-dosing strategy has yet to change. In particular, the committee was awaiting formal results from a large clinical trial in Costa Rica that has been comparing dosing strategies in adolescent girls. So far, the data, recently presented at a cancer conference, suggest that one dose is just as effective as two, the current CDC-backed regimen. Earlier this year, the ACIP working group focused on HPV vaccines was leaning toward supporting the dose drop, Brewer, who was part of that group, told me. The proposal to routinely recommend the vaccine as early as 9 years of age, he added, seemed likely to pass, too. (Currently, the CDC allows for HPV vaccination as early as 9 years of age, but only actively recommends it starting at 11 years of age.)

Those amendments to HPV-vaccination guidelines would make the shot simpler to get, for a wider range of children—which could dramatically increase its uptake, Gretchen Chapman, a health-psychology researcher at Carnegie Mellon University, told me: “The more you can make getting vaccinated easy and convenient, the higher vaccination rates will be.” Only about 60 percent of 13-to-17-year-olds in the U.S. are up-to-date on their HPV shots—a gap that public-health experts consider a major missed opportunity. That the shot can almost perfectly prevent infection and disease for decades is “like the fantasy we have of vaccines,” Brewer told me. Its rock-solid protection “just keeps rolling.”

But the new ACIP may see matters differently. Kennedy has yet to fill the committee’s roster, but his initial picks include individuals who appear to have a beef with HPV immunization. One member, Vicky Pebsworth, co-wrote an analysis detailing adverse events following HPV vaccination for an anti-vaccine organization, which she serves on the board of. Another new member, Martin Kulldorff, provided expert testimony in cases against the drugmaker Merck over its Gardasil vaccine, the only HPV shot available in the U.S., and received thousands of dollars from plaintiffs who accused the company of downplaying the vaccine’s risks. (A judge in North Carolina overseeing one of those cases ruled in favor of Merck; another, in Los Angeles, is going to trial later this year.) And Kennedy, an environmental lawyer, has himself been instrumental in organizing the litigation campaign against Merck—and has described Gardasil as “the most dangerous vaccine ever invented.” (Under pressure from senators, Kennedy has said that he will relinquish any proceeds from these lawsuits to his son.) He has also falsely claimed that the HPV vaccine—which data show has dramatically reduced rates of cervical cancer in the U.S. and elsewhere—“actually increases the risk of cervical cancer.” (HHS, the CDC, Pebsworth, and Kulldorff did not respond to a request for comment.)

At some point, the current ACIP might see fit to soften the existing guidelines, or even advise the CDC to remove the vaccine recommendations for certain groups. If it does, those decisions could prompt insurers to stop covering the vaccines, or disincentivize health-care providers from offering them to families. The committee could also remove the vaccine from the Vaccines for Children program, which provides shots to kids whose parents cannot afford them. (An initial agenda for the ACIP meeting scheduled to start on Wednesday initially included a recommendation vote for the HPV vaccine, as well as a vote on its status in Vaccines for Children; those items no longer appear in the CDC’s draft agenda.)

A few of the experts I spoke with raised the possibility that this new ACIP might still amend the HPV-vaccine recommendation to a single dose, but with a different rationale: not because the members are swayed by the data on its effectiveness, but because they’d support any option that cleaves a vaccine dose from the immunization schedule. Kennedy, too, seems likely to back such a move. “Any window to roll back the number of times a child receives a vaccine injection? He’s going to push for,” Alison Buttenheim, a behavioral scientist at Penn Nursing, told me.

The net effect might at first seem the same: Fewer doses of the HPV vaccine would be on the schedule. But the reasoning behind a decision can matter just as much as the end result. Robert Bednarczyk, an epidemiologist and vaccine researcher at Emory University’s Rollins School of Public Health, pointed out that, although much of the evidence so far has pointed toward one dose being enough, the case isn’t yet a slam dunk: Some of the trials investigating the  single-dose strategy are using different formulations of Gardasil, or non-Gardasil brands, which may perform differently. (The Costa Rica trial, notably, does include the same Gardasil recipe used in the U.S.) And some experts still wonder if the protection offered by a single shot may fade faster than a double-dose regimen—a more challenging aspect of vaccine protection to assess without many years of follow-up. If that’s the case, prematurely dropping the second dose could later force the U.S. to add a shot back into the vaccine schedule—a confusing message that could erode trust. The last thing the country needs now is “another hit to public confidence around vaccines,” Bednarczyk said.

How Kennedy and his allies publicly justify these choices, then, matters quite a bit. Vaccines, on the whole, are now being billed by the government not as vital, lifesaving tools, but as unnecessary risks, deserving of additional scrutiny. Of the multitude of vaccines on the childhood-immunization schedule, many people already see HPV “as the troublesome one,” Brewer told me. Its ability to prevent cancer has been underemphasized; some critics have stoked unfounded fears that, because the vaccine guards against a sexually transmitted virus, it will increase promiscuity. And unlike other vaccines recommended in the early adolescent years, such as the meningococcal vaccine and the Tdap booster—which are required by most or all states for entry into secondary school—HPV is mandated for preteens in only a handful of jurisdictions.

All of these pressures make the vaccine more vulnerable to being rejected, Chapman told me. And should Kennedy’s new vaccine team openly discard HPV doses primarily for the sake of dropping a shot, that could set a precedent—for removing other vaccines from the schedule, in part or entirely.