HPV Vaccine: HHS Updates to 1 Dose Schedule & Expert Concerns

The Department of Health and Human Services (HHS) announced a revised childhood immunization schedule on Tuesday, significantly reducing the number of vaccines universally recommended for children. The novel guidance lowers the number of recommended vaccines from 17 to 11, a change that has sparked debate among medical professionals and raised questions about the process behind the alterations.

While the Human Papillomavirus (HPV) vaccine remains recommended for all children starting at age 11 or 12, the updated schedule suggests a shift towards a single-dose regimen, a departure from previous recommendations of two or three doses. Experts note that this adjustment aligns with recent research demonstrating the effectiveness of a single dose in providing adequate protection.

The impetus for the change in HPV vaccine recommendations stems from the ESCUDDO trial, a study published in the New England Journal of Medicine in December 2025. The trial, conducted in Costa Rica between 2017 and 2025, involved over 20,000 girls aged 12-16. Researchers randomly assigned participants to receive either one or two doses of Cervarix (which is no longer available in the United States) or Gardasil 9, the currently available HPV vaccine in the U.S. Results indicated that both one and two-dose regimens of both vaccines were over 97% effective in preventing infection with HPV types 16 and 18, the primary causes of cervical cancer. A similar trial conducted in Kenya yielded comparable results, showing 98% effectiveness with a single dose.

Proponents of the single-dose approach argue that it could increase vaccine uptake by removing logistical barriers such as the need for multiple appointments and associated costs, particularly in resource-constrained settings. It would also simplify large-scale vaccination campaigns.

However, the American Academy of Pediatrics (AAP) has not yet altered its recommendations, a divergence that has caused concern among some medical professionals. Many physicians rely on AAP guidance when making vaccination decisions for their patients and the differing recommendations could lead to confusion.

Adding to the controversy, the changes were implemented by HHS without the typical involvement of an advisory committee and public comment period. Traditionally, updates to vaccine schedules are guided by recommendations from advisory groups, with opportunities for public input before the CDC finalizes any changes. This process was bypassed in this instance, raising concerns about transparency and the scientific basis of some of the alterations. According to reports, some of the changes to the schedule were not based on scientific evidence.

Experts are advising parents to consult with their pediatricians to determine the most appropriate vaccination schedule for their children, given the evolving recommendations and the potential for conflicting guidance. The CDC has not yet issued a statement addressing the concerns raised by the AAP and other medical professionals regarding the process and the scientific rationale behind the changes.