Ages 9-26 years. Gardasil is a vaccine to prevent cancers and warts caused by 4 strains of hpv virus. It is approved for females ages 9-26 years. Recently, it got approved for males also. Since most genital area hpv infections are from sexual contact, girls younger than age 9 don't need the vaccine yet. Some doctors wait until girls are teens before giving the vaccine, as that is when sexual activities can begin.
Approved > 9. Development, testing and approval of a vaccine like Gardasil takes decades & an investment of millions of dollars.As the vaccine becomes ready for human use, the developer must identify a target population (age, sex.Condition) & gather safety & effectiveness data & apply to the fda for licensure. The vaccine may be effective if given to infants, but the cost & delay to get the data was not pursued.