NEW YORK — Preteens may soon have something to celebrate: Medical experts are discussing whether one dose of a life-saving cancer vaccine, instead of two, will be enough to protect them.
Vaccination Recommendations in the United States became shattered Last year, federal officials and doctors’ organizations disagreed on the guidance and even fought in court. But both sides are considering revising long-standing HPV vaccine recommendations.
“This would represent a significant change from what has been communicated for many years about how best to protect adolescents against HPV,” said Jason Schwartz, a vaccine policy researcher at Yale University.
Here’s a look at HPV shots, which debuted 20 years ago and may now be at a crossroads.
HPV linked to thousands of cases of cancer
HPV, human papillomavirus, is the most common sexually transmitted infection in the United States.
More than 40 types of HPV can infect the genital areas of men and women, as well as the lining of the mouth and throat. Certain strains are responsible for most cases of genital warts.
HPV is also a leading cause of the nearly 50,000 cases of cancer diagnosed each year in the United States affecting these parts of the body. In fact, approximately 90% of cervical and anal cancers are attributed to HPV infectionsaccording to the Centers for Disease Control and Prevention.
In 2006, federal health officials approved the first HPV vaccine, Gardasil from Merck & Co. A second vaccine was approved in 2009, Cervarix from GlaxoSmithKline.
Both vaccines are approved for use in men and women, available for children as young as 9 years old to adults in their 20s. But they have been prioritized for 11- and 12-year-olds because the shots work best if given before someone is sexually active.
HPV vaccination recommendations have already changed
Initially, in 2006, HPV vaccinations were recommended only for girls and given as a series of three injections over six months. Boys were added in 2011, a move largely aimed at preventing them from passing a virus to girls that can cause cervical cancer.
Ten years ago, the government changed the dosage recommendations. He I dropped the number recommended doses of three to two after studies showed that this amount provided sufficient protection. Research also suggested that two doses were most effective when spaced six to 12 months apart, meaning they could be given at annual checkups.
Since then, studies in several countries have shown a dramatic decrease in infections, cases of genital warts and precancerous lesions of the cervix.
In 2020, the American Cancer Society updated its guidelines for women, increasing the age at which screenings should begin to 25, up from 21. The organization attributed the change to data showing that vaccinations led to lower rates of cervical changes, considered precursors to cancer.
The evidence continues to be favorable.
The University of Minnesota’s Vaccine Integrity Project was released this year a research journal which found that HPV vaccines reduced the risk of genital cancer in women. And a study published in April in the journal JAMA Oncology, found that vaccinated men are nearly 50% less likely to develop cancers of the head and neck, esophagus, anus or penis.
Additionally, “the duration of protection is long,” said Angela Ulrich, who led the Vaccine Integrity Project review. “We have people aged 20, 30, 40 years old who are getting protection from the HPV vaccine. »
HPV vaccination rates are lower than other vaccines
A recent CDC report found that HPV vaccination rates were lower than some other vaccines received by adolescents, at least in part because most states do not require HPV vaccination as a condition of school attendance.
Yet the HPV vaccination rate has remained stable for four consecutive years, with approximately 63% of adolescents having received both doses.
It doesn’t help that HPV shots are known to have a sharper sting. (Doctors have noted that fainting is more common after an HPV injection.)
Questions about pain are common, said Dr. Scott Hadland, who works at a Boston clinic that treats adolescents and young adults.
“Some of my patients tell me it hurts more than other vaccines they have received, but only for a moment,” he said.
The elevation of Robert F. Kennedy Jr. to U.S. Secretary of Health may not have helped in recent times. Before being appointed last year to oversee federal health agencies, Kennedy was a lawyer and consultant in lawsuits against Merck over the Gardasil vaccine, and falsely declared the vaccine increases the risk of cervical cancer.
Research suggests just one injection may be enough for girls
In January, Kennedy ordered that the number of recommended HPV doses be reduced to one, as part of a unilateral reduction in the childhood vaccination schedule.
This change was blocked by order of a federal judge, but it’s actually something medical experts have been thinking about for some time.
The idea gained attention late last year with the publication of a study in Costa Rica, which followed more than 20,000 girls for five years. The study found that a single HPV injection provided about 97% protection against cervical cancer, the equivalent of two doses.
A year earlier, in 2024, research developments prompted a CDC advisory committee to form a working group to explore the possibility of a revised recommendation. This work was interrupted when Kennedy rejected the members of the committee.
The American Academy of Pediatrics — one of the medical groups that sued Kennedy — makes its own vaccination recommendations. The body is considering changes to its guidelines, exploring questions such as whether one dose is enough for at least some people and at what age vaccination should begin, said Dr. James Campbell, chair of the organization’s infectious diseases committee.
Should children be allowed one or two injections?
Recommendations are evolving. But currently, experts advise children to receive two injections.
Although there is evidence that a single injection is enough in girls to prevent cervical cancer, there is less evidence on other types of cancer in girls. There is also a lack of data on whether a single shot provides sufficient protection for boys against the HPV-related cancers for which they are at risk, according to the Vaccine Integrity Project review.
Whether the recommendation remains two shots or is changed to one, it’s important that children are vaccinated, Hadland said.
“The benefits are very clear. It prevents cancer,” he said.
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