About two weeks ago the Cancer Research and Prevention Foundation held a teleconference on HPV and cervical cancer, with the aim of educating us on the HPV vaccine. The two speakers were from Merck, a maker of one of the two vaccines, and Moffitt, a cancer center in Tampa, Florida.
There is a lot of scientific information that I got down, but basically, here's what we know: HPV strains 16 and 18 cause 70% of cervical cancer cases, and strains 6, 11, 16 and 18 combined cause about 50% of more mild cervical changes and 90% of the genital warts cases.
The Merck vaccine is quadravalent, and contains protection against strains 6, 11, 16 and 18. It should be used in women who have not been exposed to HPV, so women who are not yet sexually active. Clinical trials show that Gardasil is over 95% effective in women who have none of those four strains of HPV. However, women who are sexually active may have at least one of those four strains - clinical trials showed that 73% of sexually active women had none of the four strains, 20% had only one type, 6% had two types, 1.2% had three types and only 0.1% had all four types of HPV in the vaccine.
While there are only about 3,000 deaths from cervical cancer a year, much of those are due to a lack of access to care. Well, to be more specific, a failure to access federal and state funded cervical screening programs. The lives lost from each cervical cancer case is approximately 29 years per woman, which means this is affecting fairly young women! Nonetheless, HPV is fairly ubiquitous, and before the Pap, cervical cancer was a huge killer of women in America.
Unfortunately, those who are already exposed to HPV will not benefit from the vaccine. The HPV vaccine, therefore, is not to be used as a treatment, but must be used prophylactically, among women who have not yet been exposed (and preferably, not had sex). Legislation has been introduced in at least 39 states to fund or require the vaccine, mostly for girls entering about 6th grade. Only Virginia and Washington, DC have passed such laws. Federal laws thus far have been focused on prohibiting federal funds from paying for the vaccine, or have been related to access or reimbursement issues. NPR did a story on it.
We also know that some cases of cervical cancer are not caused by these strains of HPV, which is why HPV testing is not recommended as a screening tool. It's really the effect of the virus, not the presence of the virus, that I think is the concern. In poor areas, Pap tests are not widely available, but a much simpler test may get the job done. The method described is part of a colposcopy, the next medical step in the U.S. for a woman who has an abnormal Pap smear.
And we're still only talking about the vaccine with respect to girls, not boys, which I think is a shame. Obviously, males spread HPV, but faithful readers will know that men can get cancers from HPV as well. And, a side note, you shouldn't douche anyway, but lemon juice? Bad for cervical cancer, and I don't imagine it feels all that great either.
