Thanks for the post and your excellent questions. Let's talk a bit about the HPV vaccine first.
Gardasil, the HPV vaccine licensed last summer, is designed to protect against the HPV types most commonly detected in both cervical cancers and genital warts, and in clinical trials has shown near 100% effectivness at preventing both persistent infection and diseases related to these four HPV types. Gardasil does not protect against all HPV types, and regular screening (such as Pap tests) is still recommended for women who receive the vaccine. The vaccine has shown to be safe, with the most common side effects reported being redness and irritation at the site of infection.
The HPV vaccine is approved and recommended for women ages 13-26 who have not yet received it; there is data to indicate that women who already have HPV and receive the vaccine still get good protection against the HPV types they don't have, but less is known about how well Gardasil might protect women who already have one or more types of HPV. Studies are ongoing.
Gardasil does not have any therapeutic value in treating, or preventing the transmission of, HPV types you may already have. Using the vaccine in men and women over age 26 is called "off label" use which can be done at the discretion of your physician. Speak with your health care provider if you have questions about whether or not the vaccine is right for you.
Latex condoms may provide some protection against the transmission of HPV with a new partner. However, condoms are limited to only providing protection for skin that is covered. If virus is present on skin that is not covered, and there is skin-to-skin contact with that area, then transmission may still be possible. Nonetheless, we recommend the use of latex condoms as studies show that using them consistently reduces the risk of contracting HPV and other STDs.
Keep this in mind, too. The immune system is thought to assert itself over time and actually reduce the virus to very low levels. When this happens, it isn't clear to researchers if HPV is eliminated completely, or simply at a point where it's undetectable. There is no way to predict when this natural suppression may occur, however, and the virus may be contagious to a new partner in the meantime. Still, HPV does not appear to be persistent in most cases.
In regard to cervical HPV, if a person has been successfully treated (if needed) and has had no cervical abnormalities for a year or more, some experts would consider the risk of HPV transmission with a new partner to be extremely low.
Unfortunately, it is not known how long the period of being contagious may last, or when HPV could recur. However, the virus does seem to be transient for most.
I hope this helps.
All the best,