A new study published by the BMJ (British Medical Journal) shows that vaccination against some types of human papillomavirus (HPV) can give strong and sustained protection against pre-cancerous growths of the cervix and genital warts.
The quadrivalent HPV vaccine can help prevent low grade lesions due to HPV and prevent warts, according to an international study.
HPVs cause around 500,000 incidents of cervical cancer annually around the world and 10 million incidents of high grade cervical intraepithelial neoplasia, which are immediate precursors to malignant cancerous growths (cancer). Each year 30 million women and men develop anogenital warts (condyloma acuminata) or low-grade cervical growths, estimates show.
The vaccine for HPV types 6,11,16 and 18 help prevent about 90% of genital warts and around 70% of cervical cancers, although the potential to prevent low grade cancerous growths is not yet certain.
An international team of scientists embarked on a study to find out how effective the vaccines were in preventing low grade disease.
They used results from 17,622 women aged 16-26 who were enrolled in two studies between December 2001 and May 2003. These women were enrolled from hospital associated health centers or primary care centers in 24 countries.
By random selection, they were split into two groups:
- One groups was given three doses of HPS vaccine (for types 6,11,16 and 18) at day 1, month 2, and month 6 of the study.
- The other group being given a placebo (a dummy vaccine without any active ingredient).
Results showed that the vaccine was highly effective (96-100%) for preventing low grade lesions attributable to HPV types 6,11,16 and 18 for up to four years amongst previously unexposed women.
The vaccine was also very effective against any lesion of any HPV type, it helped reduce:
- 30% of cervical low-grade growths
- 48% of vulvar
- 75% of vaginal low-grade growths
- It also reduced Genital warts by 83%
According to the authors the prolonged effectiveness of the vaccine preventing low grade lesions is important, the authors conclude :
These lesions occur shortly after infection and a reduction in these lesions will be the earliest clinically noticeable health gain to be realised by HPV vaccination.
Low-grade cervical and vulvovaginal lesions are important from a public health perspective, as the diagnosis, follow-up, and treatment of these common lesions are associated with substantial patient anxiety, morbidity, and healthcare costs.
The FUTURE I/II Study Group
Published 20 July 2010, doi:10.1136/bmj.c3493
Written by Joseph Nordqvist