The article focuses on the phase III efficacy trials for two vaccines against human papillomavirus (HPV). It states that the Gardasil, which is produced by pharmaceutical giant Merck, was the first vaccine to enter phase III efficacy trials. It says that the second vaccine Cervarix from GlaxoSmithKline has started its phase III trial in May 2003. It adds that other effects could become apparent as countries start mass HPV vaccination.