The virus lives in the skin or mucous membranes and usually causes no symptoms. Since a majority of HPV infections have no signs or symptoms, most people that are infected are completely unaware and can continue to transmit the virus to sex partner(s).
Depending on the type of HPV, some women have infections that cause abnormal cell growth (dysplasia) on the female cervix. A woman may only find out she has HPV when her annual Pap smear results indicate abnormal cervical cell changes.
Other types of HPV cause visible genital warts. In women, these growths may develop inside the vagina, where they are hard to detect. They can also develop on the lips of the vagina or around the anus. In men, they usually appear on the penis, but they are also found on the scrotum or around the anus.
The growths are typically soft, moist, pink or red swellings and are usually painless but may itch. If allowed to grow, they can block the openings of the vagina, urethra, or anus and become very uncomfortable. They can be single or multiple growths or bumps, raised or flat, small or large and sometimes form a cauliflower-like shape. Depending on their location, genital warts can cause sores and bleeding.
Merck & Company's vaccine, Gardasil, is a quadravalent vaccine that is protective against HPV strains 6, 11, 16 and 18, which can lead to genital warts and cervical cancer. Gardasil was approved by the Food and Drug Administration (FDA) in June of 2006.
GlaxoSmithKline's vaccine, Cervarix, is a bivalent non-infectious recombinant, AS04-adjuvanted vaccine that is protective against strains 16 and 18 HPV viruses, which can lead to cervical cancer. Cervarix was approved by the FDA in October of 2009.
Gardasil is administered intramuscularly as 3 separate 0.5-mL doses according to the following schedule: first dose at elected date; second dose: 2 months after the first dose; third dose: 6 months after the first dose.
Cervarix is administered intramuscularly as 3 separate 0.5-mL doses according to the following schedule; first dose at elected date; second dose: 1 month after the first; third dose: 6 months after the first dose.
Each vaccine series should be completed using the same product; you can not use HPV vaccines interchangeably within the 3 dose series.