Is it necessary to wait for clearance of a skin Human Papillomavirus (HPV) infection before initiating the 3-dose series of Gardasil (Human Papillomavirus vaccine)

HPV Vaccination with Existing Skin HPV Infection

It is not necessary to wait for clearance of a skin HPV infection before initiating the Gardasil 3-dose series. 1, 2

Rationale for Immediate Vaccination

The Advisory Committee on Immunization Practices (ACIP) explicitly states that individuals who might have already been exposed to HPV should still be vaccinated, without waiting for clearance of existing infections 1. This recommendation is based on several important considerations:

• Existing HPV infections are typically with only one or a few HPV types, while the vaccine protects against multiple types (6,11,16,18 in quadrivalent Gardasil, and 9 types in the newer 9-valent Gardasil-9) 2
• The vaccine provides protection against HPV types not already acquired, even in those with existing infections 1
• It is not possible for clinicians to accurately assess which specific HPV types a person has been exposed to 1
• The risk for new HPV infections continues as long as a person is sexually active 1

Important Clinical Considerations

Vaccine Efficacy with Existing Infection

• The vaccine is prophylactic, not therapeutic - it will not treat or clear existing HPV infections 3
• However, vaccination can still prevent:
  • New infections with different HPV types
  • Re-infection with the same HPV type after clearance
  • Autoinoculation from one site to another 3

Testing Before Vaccination

• Pap testing, HPV DNA testing, or HPV antibody screening are not needed before vaccination at any age 1
• Pre-vaccination testing would not be helpful since:
  • Commercial tests don't identify all HPV types
  • Testing doesn't change vaccination recommendations
  • Most sexually active adults have been exposed to some, but not all, vaccine-targeted HPV types 2

Vaccination Schedule

• For individuals aged 15-26 years: 3-dose schedule (0,1-2, and 6 months) 2
• For individuals aged 9-14 years: 2-dose schedule (0 and 6-12 months) 2
• If the vaccination schedule is interrupted, it does not need to be restarted 1

Special Considerations

Skin HPV vs. Genital HPV

• Skin (cutaneous) HPV types are generally different from the high-risk mucosal types that cause cancer 4, 5
• The HPV vaccine targets specific high-risk types (primarily HPV 16 and 18) and some low-risk types (6 and 11) that cause genital warts 6
• Having a skin HPV infection does not reduce the benefit of vaccination against the targeted HPV types 1

Risk Factors for HPV-Related Cancers

• Multiple sex partners, early sexual activity, inconsistent barrier protection use, other STIs, immunocompromised state, alcohol use, and smoking increase risk for persistent HPV infections 4
• Vaccination is the primary method of prevention against HPV-related cancers 4

Common Pitfalls to Avoid

1. Delaying vaccination unnecessarily: Waiting for clearance of skin HPV infection provides no benefit and only delays protection against other HPV types 1

2. Assuming prior exposure means vaccination is not beneficial: Even with prior HPV exposure, most individuals will not have been exposed to all vaccine-targeted types 2

3. Confusing therapeutic and prophylactic effects: The vaccine prevents new infections but does not treat existing ones 3

4. Forgetting follow-up doses: All doses in the series are necessary for optimal protection 2

In conclusion, the presence of a skin HPV infection should not delay initiation of the Gardasil vaccination series. The vaccine will still provide protection against HPV types not already acquired, which can prevent future HPV-related diseases including cancers.