Vaccines authorized for the German market are targeted against HPV types 16 and 18 because these are two of the most common high-risk types in Germany. Vaccination provides protection before infection with these HPV types, thus preventing HPV infection, without which cervical cancer does not develop. As sexual contact is the main route of transmission of HPV, vaccination is most effective when performed in girls and young women aged between 12 and 17 who are not yet sexually active. The review, which focuses on studies investigating the efficacy of vaccination in short- and long-term follow-up, is therefore restricted to HPV-naive girls and women. According to the authors’ calculations, in long-term follow-up vaccination is 94% effective in preventing randomly detected infection, 95% effective in preventing persistent infections, and 86% effective in preventing gradeï¿½2 or above cervical intraepithelial neoplasia (CIN 2+). However, smaller study and participant numbers mean that the quality of the evidence on long-term protection is lower than that on short-term protection.
In order to improve the quality of evidence on long-term protection, the authors call for continuation of randomized controlled trials to ascertain the duration of HPV vaccine protection and further observational studies assessing the efficacy of vaccination.
source : http://www.sciencedaily.com/releases/2014/09/140925082231.htm