A recent medical development, a vaccine against select human papilloma virus (HPV) strains, shows that there is a misunderstanding amongst the general public, including physicians, about how vaccines work. HPV is a sexually transmitted disease that can cause cervical cancer (see "Cervical Cancer: Causes and Prevention"). Just like any other vaccine, the purpose of an HPV vaccine is prevention of the disease in those who have not been infected with it prior to the drug's administration. The human system is known to clear HPV on its own, but administration of the HPV vaccine does not improve the frequency of this happening.
A recent study featured in the Journal of the American Medical Association focused on the HPV vaccine's potential as a treatment for pre-existing HPV. The study was conducted in Costa Rica and included 2,200 women ages eighteen to twenty-five. The HPV vaccine Cervarix was used for the study. Cervarix is awaiting Food and Drug Administration (FDA) approval in the U.S. Allan Hildesheim, senior investigator of the cancer epidemiology and genetics department at the U.S. National Cancer Institute, admitted that there was little hope that the vaccine would result in any treatment of pre-existing HPV. The study was prompted by the confusion on this point and reaffirmed what should be the general understanding -- this vaccine is preventive, not a treatment.
The recommended administration of the vaccine is before girls become sexually active (see "Cervical Cancer-Fighting HPV Vaccine Recommended for Girls Eleven and Up"). It is important to note that the currently available HPV vaccines only protect against select strains of the virus. These strains happen to be the ones responsible for the majority of cervical cancers, but are not responsible for all of them, and therefore women should continue regular pap smears. At the same time, women are encouraged to get the vaccine up to age twenty-six even if they have HPV. Although the vaccine will not eradicate HPV that is already present, it may protect from other strains that have not been contracted.
Krystal Wilson is a research intern at the American Council on Science and Health (ACSH.org, HealthFactsAndFears.com).
See also: "A Cancer Vaccine -- Maybe."
