Can Cervarix Be Used as the Second Dose After Starting with Gardasil?
Yes, Cervarix can be used to complete the HPV vaccination series if Gardasil was used for the first dose, though this represents an off-label heterologous (mixed) vaccine schedule. 1
Guideline-Based Recommendations
The most recent guidance from Taiwan (2025) explicitly states that the 9vHPV vaccine may be used to continue or complete a series for individuals who initiated their vaccination with 4vHPV or 2vHPV vaccines (which includes Cervarix as the bivalent vaccine). 1 This expert opinion recommendation extends to heterologous vaccine schedules in general.
The CDC recommends that if an individual was vaccinated with an unknown HPV vaccine product or if the previously used product is unavailable, women may receive any available HPV vaccine to continue or complete the series. 1 This provides clear support for switching between vaccine types when necessary.
Key Practical Considerations
When to Consider Switching Vaccines
- Product availability issues: If Gardasil is unavailable at the time the second dose is due, switching to Cervarix is acceptable rather than delaying vaccination 1
- Unknown vaccine history: When the initial vaccine type cannot be determined, any available HPV vaccine can be used to complete the series 1
Important Caveats About Mixed Schedules
- No direct efficacy studies exist: No RCTs have evaluated the clinical effectiveness of heterologous HPV vaccination regimens 1
- Immunogenicity data is limited: The safety and immunogenicity of mixed vaccine schedules have not been formally studied in clinical trials 1
- Coverage differences matter: Gardasil (quadrivalent) covers HPV types 6,11,16, and 18, while Cervarix (bivalent) covers only types 16 and 18 2, 3
Safety Profile Considerations
The 2vHPV vaccine (Cervarix) has been associated with significantly higher rates of systemic adverse events compared to both 4vHPV and 9vHPV vaccines, though serious adverse events remain rare with all HPV vaccines. 1 This is worth discussing with patients when switching from Gardasil to Cervarix, as they may experience more systemic symptoms (fever, headache) than they did with their first dose.
Dosing Schedule Completion
- Continue the standard schedule: Administer the second dose 1-2 months after the first dose, regardless of vaccine type used 4, 5
- Third dose timing: Give the third dose 6 months after the first dose, maintaining minimum intervals of at least 12 weeks between doses 2 and 3 4, 5
- Do not restart the series: If switching vaccine types, continue from where the patient left off rather than restarting 5
Clinical Bottom Line
While using Cervarix after starting with Gardasil is supported by expert opinion and CDC guidance for situations where the original vaccine is unavailable, the preferred approach is to complete the series with the same vaccine product when possible. 1 However, switching vaccines is far better than leaving the patient incompletely vaccinated, as partial vaccination provides substantially less protection than completing the full series. 4
The lack of protection against HPV types 6 and 11 (which cause genital warts) when switching from Gardasil to Cervarix should be explained to patients, though both vaccines provide equivalent protection against the high-risk oncogenic types 16 and 18 that cause approximately 70% of cervical cancers. 2, 3