Researchers find HPV vaccine safe, effective for 4.5 years

Three immunizations with a bivalent human papillomavirus (HPV)-16/18 L1 virus-like particle AS04 vaccine safely induces sustained high levels of antibodies that provide long-term protection against HPV-16 and -18 infection and associated cervical lesions and possibly against HPV 45 and HPV 31-the third and fourth most common HPV types associated with cervical cancer-for up to 4.5 years.

The information comes from follow-up data from a randomized, multicenter, double-blind, placebo-controlled trial paid for and coordinated by the manufacturer of the vaccine. The findings put the vaccine one step closer to widespread use and prevention of cervical cancer.

The authors of the data found that more than 98% seropositivity was maintained for HPV-16 and -18 during the extended follow-up period. In terms of its efficacy with various HPV-16 and HPV-18 endpoints, the vaccine was 96.9% effective against incident infection, 94.3% effective against the 6-month definition of persistent infection, 100% effective against the 12-month definition of persistent infection, and 100% effective against cervical intraepithelial neoplasia lesions associated with the vaccine types.

Harper DM, Franco EL, Wheeler CM, et al. Sustained efficacy up to 4.5 years of a bivalent L1 virus-like particle vaccine against human papillomavirus types 16 and 18: follow-up from a randomised control trial. Lancet. 2006;367:1247-1255.