Both cervical cancer and genital warts are caused by a sexually transmitted virus called HPV. Today, there's a vaccine that can protect some from this virus's effects. In 2006, the FDA announced the approval of Gardasil, the first vaccine to protect against harmful strains of the human papillomavirus, or HPV. HPV actually refers to a group of about 100 similar viruses, which affect over six million Americans. About 40 of these 100 strains are transmitted through sexual contact. Gardasil protects against four specific strains of HPV, numbers 6 and 11, which cause 90 percent of all cases of genital warts, and numbers 16 and 18, which are responsible for 70 percent of cervical cancers. Gardasil is approved for use in females between the ages of 9 and 26, although - since the virus is passed sexually - girls yet to have intercourse are the best candidates. Women who are already sexually active can still receive the vaccine, however, even if they already have one strain of HPV. Once the decision is made to have the vaccine, it is given as a set of three injections over six months. The protection provided by Gardasil is not in place until you've received all three injections. Side effects of the vaccine may include redness and itching at the injection site, as well as nausea and fever. If you think you might be a candidate to receive Gardasil, talk to your health care provider about the vaccine.