Cervical cancer vaccine
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Here is a comprehensive overview of the cervical cancer vaccine (HPV vaccine) based on authoritative medical textbooks:
HPV Vaccine (Cervical Cancer Vaccine)
Background
Human papillomavirus (HPV) is the primary cause of cervical cancer. HPV types 16 and 18 alone account for approximately 66–70% of all cervical cancers worldwide. Additional high-risk types (31, 33, 45, 52, 58) account for a further ~15%. The HPV vaccines are prophylactic — they prevent new infections but do not treat established HPV disease.
Available Vaccines
Three HPV vaccines have been approved in the United States, all composed of noninfectious recombinant virus-like particles (VLPs) made from the HPV L1 capsid protein:
| Vaccine | Year Approved | HPV Types Covered |
|---|---|---|
| Bivalent (Cervarix) | 2007 | 16, 18 |
| Quadrivalent (Gardasil) | 2006 | 6, 11, 16, 18 |
| 9-valent (Gardasil 9) | 2014 | 6, 11, 16, 18, 31, 33, 45, 52, 58 |
The bivalent and quadrivalent vaccines are no longer available in the United States; the 9-valent vaccine (9vHPV) is now the only one in use and can theoretically prevent over 90% of HPV-caused cancers.
Types 6 and 11 (in quadrivalent and 9-valent) cause genital warts (condylomata acuminata), not cancer.
Efficacy
- For individuals not previously infected, the vaccine is ~100% effective in preventing persistent infection by the targeted HPV types.
- Highly effective against preneoplastic lesions: cervical intraepithelial neoplasia (CIN I, II, III) and anal intraepithelial neoplasia (AIN).
- Does not affect pre-existing infections — vaccination must occur before exposure to be effective.
- Vaccine-induced immunity appears to last at least 10 years.
Recommended Schedule (United States)
| Age of Initiation | Schedule |
|---|---|
| 9–14 years | 2 doses at 0 and 6–12 months |
| 15–26 years (or immunosuppressed) | 3 doses at 0, 1–2, and 6 months |
| 27–45 years | Shared clinical decision-making (not universally recommended) |
- Routine vaccination is recommended for both girls and boys at age 11–12 years (can start at age 9).
- Males were added to the recommendation in 2011.
- Catch-up vaccination is recommended for all persons through age 26.
Important Limitations
- Vaccinated individuals should continue Pap smear and HPV screening, because other non-vaccine HPV genotypes can still cause cervical cancer.
- The vaccine does not eliminate risk entirely — screening programs remain essential.
Adverse Reactions
- Local: Injection site pain, redness, swelling (most common)
- Systemic: Dizziness, syncope (fainting — patients should be observed post-injection), nausea, vomiting, fatigue, headache, fever, urticaria
Broader Cancer Prevention
The HPV vaccine also reduces risk of:
- Anal cancer (HPV-related)
- Oropharyngeal cancer (HPV-related, particularly HPV-16)
- Anogenital warts
Sources:
- Goldman-Cecil Medicine, 26th Ed.
- Harrison's Principles of Internal Medicine, 22nd Ed.
- Jawetz, Melnick & Adelberg's Medical Microbiology, 28th Ed.
- Sherris & Ryan's Medical Microbiology, 8th Ed.
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