Persistent cervical infection with high-risk human papillomavirus (HPV) genotypes is necessary for the development of cervical cancer and its immediate precursor lesions, CIN3
HPV16 & 18 contributes to about 70% of cervical cancers
HPV 31, 33, 45, 52, 58 are responsible for 20% cervical cancers
90% HPV infections are transient, becoming undetectable within one to two years
- DNA free VLPs- empty capsids, non-infective, non-oncogenic
- Prophylactic Vaccines protect against acquisition of HPV infection and development of HPV associated disease
- Bivalent vaccine cover HPV 16, 18
- Quadrivalent vaccine cover HPV 6, 11, 16, 18
- Nonavalent vaccine cover HPV 6, 11, 16, 18, 31, 33, 45, 52, 58
- Therapeutic Vaccines induce regression of existing HPV associated lesions and are under development
Age at initiation of vaccination
- Advisory committee on immunization practices by United States recommends:
- Routine HPV Vaccination at 11-12 years, though it can be administered from 9 years onwards
- For those aged between 13 to 26 years, who have not been previously vaccinated, catch-up vaccination is recommended
- For adults 27 years or older, decision to vaccinate is made on individual basis. Likely benefit and cost-effectiveness is lower due to chances of prior exposure
- The optima timing is “Before the Sexual Debut”
Choice of vaccine
- Any of the three vaccine types can be given depending upon availability. If cost and availability is not an issue then 9- valent vaccine is recommended. Serological or HPV DNA testing not warranted
- Ideally the same formulation should be used to complete the series, bit if previous formulation is unknown or unavailable, a different formulation can be given.
- Initiation before 15 years of age- Two doses at 0 and at 6 to 12 months. If the second dose was administered less than five months after the first, the dose should be repeated.
- Initiation at age of 15 years or later- Three doses at 0, 1 to 2 and at 6 months. The minimum intervals between the first two doses is four weeks, between the second and third doses is 12 weeks, and between the first and third dose is five months.
- Immunocompromised patients- 3 doses, regardless of age
- Missed dose- vaccination series can be resumed without restarting the series.
- Not recommended during pregnancy, but if given inadvertently during pregnancy, one can continue it and complete the rest of doses after delivery
- Can be given during breast feeding
- Excellent antibody responses- seroconversion rates of 93 to 100 percent in females and 99 to 100 percent in males.
- vaccine is safe and well tolerated apart from mild injection site reactions and reports of post-vaccination syncopal events.
Post vaccination surveillance
- HPV immunization is not effective in clearing HPV infection, genital warts, or cervical intraepithelial neoplasia that is already present.
- HPV vaccine does not protect against 100 percent of types known to cause cervical cancer.
Thus, HPV vaccination status does not impact cervical cancer screening recommendations.
MBBS, MS (OBGYN), DNB, Fellow Gynae Oncology
Dr. Vandana Jain Gynaecologic Oncology