August 15, 2007

HPV Vaccine is for Prevention, not Treatment

Guest blogger Rachel Walden of Women’s Health News is posting here this week, while Christine is on vacation.

A new study released in the current issue of JAMA: Journal of the American Medical Association looked at whether the new HPV vaccine (in this case Cervarix, a competitor to Gardasil) could help clear the infection in women who already had it, and found that the vaccine is not effective as treatment.

This really should come as no big surprise – vaccines in general, like flu shots, are intended to help prevent a disease, not to cure it.

The fact that the vaccine doesn’t cure infection raises an important point, however – much of the criticism when Gardasil was released stemmed from the need to vaccinate young girls before they become sexually active, and concerns that the vaccine would encourage them to have sex (despite the lack of evidence to support that fear).

This study adds weight to the idea that vaccination prior to the initiation of sexual activity is most effective in preventing HPV infection and possible cervical cancer, and represents the best use of the vaccine. An editorial in the issue (available with subscription) also makes this point:

The lack of therapeutic efficacy of the quadrivalent HPV vaccine was considered in deliberations by the Advisory Committee on Immunization Practices (ACIP). These data, along with data demonstrating the high likelihood of acquiring HPV infection soon after onset of sexual activity and data on sexual behavior in the United States, all contributed to recommendations for routine immunization at 11 to 12 years of age. Because the vaccine has no therapeutic efficacy, the greatest effect will be realized if the vaccine is administered before sexual debut, prior to exposure to HPV.

The study is freely available online. For more information on the vaccine that is currently available in the United States, see Gardasil: What you need to know about the HPV vaccine.


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