From the Guidelines
No, a patient who missed their second dose of Gardasil 9 does not need to restart the series. They should simply receive the missed dose as soon as possible and continue with the recommended schedule from that point. Gardasil 9 is typically administered as a 3-dose series at 0,2, and 6 months for individuals who start the vaccination at age 15 or older, or as a 2-dose series at 0 and 6-12 months for those who begin vaccination before their 15th birthday. The immune system still "remembers" the first dose, so there's no need to start over regardless of how much time has passed since the missed dose. This approach is based on the understanding that the immune system develops memory cells after the initial exposure to the vaccine, and subsequent doses build upon this initial response [ 1 ]. The most important thing is to complete the full series to ensure maximum protection against the HPV types covered by the vaccine, which helps prevent HPV-related cancers and diseases.
- Key points to consider:
- The vaccine series does not need to be restarted if it is interrupted [ 1 ]
- If the series is interrupted after the first dose, the second dose should be administered as soon as possible, and the second and third doses should be separated by an interval of at least 12 weeks [ 1 ]
- Completing the full series is crucial for maximum protection against HPV-related cancers and diseases.
From the FDA Drug Label
If the person getting GARDASIL 9 misses a dose, tell the health care professional and they will decide when to give the missed dose The FDA drug label does not provide a direct answer to whether a patient should restart the series if they missed their second dose of Gardasil 9.
- The label states that the healthcare professional will decide when to give the missed dose.
- No specific guidance is given on whether to restart the series or continue with the remaining doses. 2
From the Research
HPV Vaccination Series
- The provided studies do not directly address the question of whether a patient should restart the Gardasil 9 series if they missed their second dose 3, 4, 5, 6, 7.
- However, the studies emphasize the importance of completing the vaccination series for optimal protection against HPV-related diseases 5, 7.
- The Centers for Disease Control and Prevention (CDC) and the Advisory Committee for Immunization Practices (ACIP) provide guidelines for HPV vaccination, including recommendations for missed doses, but these guidelines are not mentioned in the provided studies.
Missed Doses and Vaccine Effectiveness
- A study published in 2023 is not available in the provided evidence, but the 2025 study suggests that timely vaccination and adherence to dosing schedules are crucial for maximizing vaccine impact 5.
- The 2025 study also notes that while three doses provide optimal protection, a single dose may confer significant benefits in younger populations, but it does not address the specific scenario of a missed second dose 5.
Recommendations for Missed Doses
- There is no direct evidence in the provided studies to support a specific recommendation for restarting the Gardasil 9 series if a patient misses their second dose 3, 4, 5, 6, 7.
- Healthcare providers should consult the CDC and ACIP guidelines for recommendations on managing missed doses and completing the vaccination series.