Question: how many strains of hpv does the vaccine protect against?
Answer: All three vaccines prevent infection with HPV types 16 and 18, two high-risk HPVs that cause about 70% of cervical cancers and an even higher percentage of some of the other HPV-caused cancers (1, 2). Gardasil also prevents infection with HPV types 6 and 11, which cause 90% of genital warts (3).