Gardasil was the first successful human papillomavirus vaccine to receive regulatory approval, gaining US approval in 2006.
Manufactured by Merck, Gardasil initially protected against HPV types 6, 11, 16, and 18. Types 16 and 18 cause a large share of cervical cancers, while types 6 and 11 cause most genital warts. The vaccine uses virus-like particles rather than live virus, so it cannot cause HPV infection.
Gardasil’s approval marked a major cancer-prevention breakthrough because persistent infection with certain HPV types can lead to cervical, anal, penile, vulvar, vaginal, and some head-and-neck cancers. Vaccination works best before exposure to HPV, which is why programmes commonly target adolescents.
Cervarix was another early HPV vaccine, but it was approved later in the United States and targeted fewer HPV types. Gardasil 9 subsequently broadened protection to nine types.