Medical experts weigh whether one HPV vaccine dose is sufficient as recommendations remain in flux
HPV is the most common sexually transmitted infection in the U.S. and is linked to roughly 50,000 cancer cases diagnosed annually, including approximately 90% of cervical and anal cancers. The HPV vaccine, first approved in 2006, is currently recommended in a two-dose series for preteens. Emerging research, including a study of more than 20,000 girls in Costa Rica, suggests a single dose may provide about 97% protection against cervical cancer — comparable to two doses.
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The two-dose HPV vaccination schedule that has been standard in the United States for the past decade may be approaching a revision, as medical experts assess whether a single shot offers adequate protection against a virus responsible for tens of thousands of cancer cases each year.
The HPV vaccine debuted in 2006 as a three-dose series recommended for girls only. Over time, boys were added to the guidelines, and in 2016 the recommended number of doses was reduced from three to two after studies showed the lower number provided sufficient protection. The current schedule calls for two shots spaced six to twelve months apart, typically given to 11- and 12-year-olds before they become sexually active, according to the Associated Press.
Research supporting a potential further reduction has grown in recent years. A study published in 2025 tracked more than 20,000 girls in Costa Rica over five years and found a single dose provided roughly 97% protection against cervical cancer. A separate study published in April in the journal JAMA Oncology found vaccinated males were nearly 50% less likely to develop cancers of the head, neck, esophagus, anus, or penis. A review by the University of Minnesota's Vaccine Integrity Project also found that HPV vaccines had lowered the risk of genital-area cancers in women and that protection appeared durable, with vaccinated individuals showing benefits decades later.