Prophylactic Vaccines Against Human Papillomavirus [Internet]

Excerpt

Background More than 120 subgroups of HPV have been identified, and at least 14 of these are oncogenic types. Persistent HPV infections are necessary, but not sufficient for development of cervical cancers. HPV types 16 and 18 cause about 70% of cervical cancers and HPV 6 and 11 cause 90% of anogenital warts. HPV infection is common in sexually active women. Most infections are incidental but some infections are persistent with a higher risk to generate cellular abnormalities. Two vaccines against human papillomavirus are developed, Gardasil® and Cervarix®. Both vaccines are type specific and are directed against the two most common causes of cervical cancer in the world, type 16 and 18. Gardasil, in addition, includes HPV 6 and 11 that are related to anogenital warts.

Methods The systematic review was performed according to general principles of HTA. The work was carried out together with a review team of external professionals. Systematic searches were performed after published systematic reviews and randomized controlled trials in international databases.

Results Ten randomized controlled trials are included in the report, of which two are follow-up studies. More than 5000 participants are included. The studies shows high HPV type specific vaccine efficacy against incident/persistent infections, in addition to cytological and histological endpoints within the tested time interval. No serious adverse events related to vaccination, occurred in either vaccine or control groups. Most included participants, both in the vaccine and control group, had injection site adverse events as pain, swelling and redness. Most adverse events were of mild or moderate intensity.

Conclusion The included studies show high HPV type specific vaccine efficacy against incident/persistent infections, in addition to a limited number of cytological and histological endpoints within the tested time interval. The follow-up time is too short (< 4 years) to conclude about the duration of the vaccine effect. The requirements of booster doses are still unknown. The longterm data regarding effects and sideeffects of the two vaccines will be important.

Keywords: Papillomavirus Infections; Human papillomavirus 16; Human papillomavirus 18; Human papillomavirus 6; Human papillomavirus 11; Vaccines; Cancer Vaccines.