Source: National Cancer Institute End-of-trial results from a trial testing Cervarix, a vaccine against human papillomavirus (HPV) types 16 and 18, showed that the vaccine continued to provide substantial protection against cervical precancers 4 years after vaccination. Cervarix provided almost complete protection in young women who had no evidence of exposure to HPV at the time of vaccination. The vaccine provided less protection for the total vaccinated cohort and was less effective with increasing age at vaccination. These findings reflect the vaccine’s lack of effectiveness against infections acquired before vaccination. The vaccine also partially protected women against four types of HPV that are not targeted by the vaccine. (Although HPV-16 and -18 cause about 70 percent of cervical cancers worldwide, as many as 15 HPV types can cause cancer.) These results from the PATRICIA trial (Papilloma Trial against Cancer in Young Adults) were published online November 9 in Lancet Oncology in two separate papers, available here and here. The PATRICIA trial enrolled 18,644 young women between the ages of 15 and 25 from 14 countries. The participants were randomly assigned to receive either three doses of Cervarix or three doses of a hepatitis A vaccine as a control. Results from the interim analysis, published in July 2009, showed that the vaccine greatly reduced the risk of grade 2 cervical intraepithelial neoplasias and higher (CIN2+). The new analysis shows that, 4 years after vaccination, Cervarix provided complete protection against grade 3 cervical intraepithelial neoplasias or higher (CIN3+) associated with HPV-16 and [...]