Is One HPV Vaccine Dose Enough? New Research & Guidelines

Recent research is prompting a re-evaluation of the Human Papillomavirus (HPV) vaccine schedule. The Department of Health and Human Services (HHS) announced changes to universally recommended childhood vaccines, reducing the number from 17 to 11. Despite this broader shift, the HPV vaccine remains recommended for all children at age 11 or 12, but new guidance suggests a single dose may now be sufficient, a departure from previous recommendations of two or three doses.

A Changing Understanding of HPV Vaccine Effectiveness

Initially, the HPV vaccine was administered in a three-dose regimen. This was later revised to two doses based on real-world research demonstrating comparable effectiveness. Now, findings from the ESCUDDO trial, published in the New England Journal of Medicine in December 2025, indicate that even a single dose could provide adequate protection.

Did You Know? The ESCUDDO trial enrolled over 20,000 girls ages 12-16 in Costa Rica beginning in 2017.

The ESCUDDO trial compared one and two doses of both Cervarix (protecting against HPV types 16 and 18, responsible for approximately 70% of cervical cancers) and Gardasil 9 (protecting against nine HPV types linked to cancer and genital warts). Researchers found over 97% effectiveness across all groups, suggesting a single dose of either vaccine is as effective as two in preventing infection from HPV types 16 and 18. A similar trial conducted in Kenya yielded comparable results, with 98% effectiveness for one dose of either vaccine against HPV 16 and 18.

Implications for Public Health

A shift to a single-dose HPV vaccine schedule could significantly improve vaccine uptake. Reducing the number of required doses eliminates logistical barriers, such as the need for multiple appointments and associated costs like transportation and time off work. This simplification could be particularly impactful in countries with limited resources.

Expert Insight: Reducing the number of doses required for the HPV vaccine could address a critical public health challenge by making protection against HPV-related cancers more accessible and achievable on a global scale.

However, the American Academy of Pediatrics (AAP) has not yet adjusted its recommendations, raising concerns about potential confusion among healthcare providers who often rely on AAP guidance. Furthermore, the HHS decision to alter the vaccine schedule was made without the typical advisory committee review and public comment period, a process usually followed for such changes.

Some of the other changes to the vaccine schedule announced by HHS were not based on scientific evidence, reinforcing the need for parents to consult with their pediatricians regarding the most appropriate vaccination plan for their children.

Frequently Asked Questions

What did the ESCUDDO trial investigate?

The ESCUDDO trial compared the effectiveness of one dose versus two doses of both Cervarix and Gardasil 9 vaccines in preventing HPV infection in girls ages 12-16 in Costa Rica.

Which HPV vaccines were studied?

The ESCUDDO trial studied Cervarix, which protects against HPV types 16 and 18, and Gardasil 9, which protects against nine HPV types.

What is the concern regarding the AAP’s current recommendations?

The AAP has not changed its recommendations to reflect the new research suggesting a single dose may be sufficient, which could cause confusion among doctors.

Will these changes to the HPV vaccine schedule ultimately lead to wider adoption and improved public health outcomes remains to be seen.