Proactive HPV vaccination at age 9 better prevents infection and improves vaccine series completion. Because national organizations recommend starting the vaccine at different ages, we sought to understand the impact of these recommendation frames. In 2022, we surveyed 2,527 US clinical staff (45% physicians) who provide HPV vaccine for children. We randomized respondents to one of three frames based on HPV vaccine recommendations of national organizations or a no-recommendation control, and assessed willingness to recommend HPV vaccine for children ages 9-10. Respondents also reported perceived benefits of HPV vaccination at ages 9 or 12. Recommending HPV vaccination "at ages 11-12" led to lower willingness to vaccinate at ages 9-10 than control (37% vs. 54%, p < .05). Recommending vaccination "at ages 9-12" led to similar willingness as control. However, "starting at age 9" led to higher willingness than control (63% vs. 54%, p < .05). Results were similar across respondents' training, specialty, or years in practice, or their clinic's rurality or healthcare system membership. More common benefits of recommending at age 9 than 12 were avoiding the topic of sex (24% vs. 10%, OR = 2.78, 95%CI: 2.23, 3.48) and completing the vaccine series before age 13 (56% vs. 47%, OR = 1.44, 95%CI: 1.23, 1.68). Less common benefits for age 9 were having parents ready to talk about HPV vaccine and agreeing to vaccination (both p < .05). An effective way to encourage proactive HPV vaccination is to say that it starts at age 9. Aligning national recommendations to start at age 9 can promote timely vaccination.
Keywords: HPV; communication; experiment; pediatrics; recommendation; survey; vaccination.