There are three HPV vaccines. The vaccines cover a different number of HPV subtypes: One of them covers for two , one with four and the newest one that covers NINE subtypes. The 9 subtype vaccine offers a small advantage over the quadrivalent (4) vaccine. The added protection against infection and disease caused by HPV types 31, 33, 45, 52, and 58 offers the potential to prevent an additional 30 to 35% more high-grade cervical lesions on females and to increase cervical cancer prevention from approximately 70% to 90%.
The key is to vaccinate BEFORE sexual contact. The HPV vaccine has no impact on HPV infections acquired before vaccination. The 9-valent vaccine is 96.7% effective against the 9 HPV subtypes that it immunizes against. This is amazing! There are lots of medicines and vaccines that are not this effective. The CDC suggests the vaccine be given at age 11 or 12, but may be started at age 9. This vaccine should be given to both males and females as it has shown to decrease risk of oral cancers AND cervical cancers.
For more information, look at http://www.cdc.gov/hpv/parents/vaccine.html