Which countries have adopted a single-dose Human Papillomavirus (HPV) vaccination regimen?

Countries That Have Adopted Single-Dose HPV Vaccination

Currently, there is limited evidence in the provided materials about specific countries that have officially adopted a single-dose HPV vaccination regimen, though Thailand has been conducting research on single-dose effectiveness.

Background on HPV Vaccination Schedules

• Traditionally, HPV vaccines were licensed and recommended as a three-dose series, particularly for individuals starting vaccination at age 15 or older 1, 2
• For younger individuals (ages 9-14), a two-dose schedule has been widely recommended in many countries 3
• The World Health Organization (WHO) has recently updated its position to include a single-dose regimen as an alternate schedule, which is gaining traction globally 4, 5

Research on Single-Dose Effectiveness

• Recent studies have shown promising evidence that a single dose of HPV vaccine may provide adequate protection against HPV infection 6, 4
• Post-hoc analyses of randomized trials have found high vaccine effectiveness following a single dose of vaccine, though some biases exist in observational studies 6
• The discovery that only a single dose may be needed could make equitable access to HPV vaccines possible, especially in resource-limited settings 4

Country-Specific Implementation

• Thailand has been conducting an effectiveness study comparing single-dose versus two-dose bivalent HPV vaccination (CERVARIX®) in school-based programs since 2018 7
• The study involves 8,000-9,000 female students in two provinces, with one province assigned the single-dose regimen and the other the standard two-dose regimen 7

Potential Impact of Single-Dose Adoption

• Broad adoption of a single-dose HPV vaccine regimen would expand access by improving supply-demand balance, increasing affordability, and simplifying logistics 5
• This approach could be particularly beneficial in resource-limited settings where the burden of cervical cancer is disproportionately high 4
• Single-dose schedules could accelerate efforts to control cervical cancer globally by increasing vaccination coverage 4

Current Standard Recommendations

• In the United States, the Advisory Committee on Immunization Practices (ACIP) still recommends:
  • Two doses for individuals who initiate vaccination before age 15 1
  • Three doses for individuals who initiate vaccination at ages 15-26 and for immunocompromised persons regardless of age 2
• The American Cancer Society endorses HPV vaccination for all persons through age 26 who are not adequately vaccinated 1

Considerations for Future Implementation

• Additional data on the durability of protection from a single dose is still being gathered 4
• Countries considering single-dose implementation will need to evaluate effectiveness in both high-income and low-income settings 4
• Integration with cervical cancer screening programs may be necessary to accelerate cervical cancer control 4