HPV Vaccination — More Answers, More Questions

"Policymakers, clinicians, and parents have a keen sense of urgency about HPV vaccination. On one hand, the vaccine has high efficacy against certain HPV types that cause life-threatening disease, and it appears to be safe; delaying vaccination may mean that many women will miss an opportunity for long-lasting protection. On the other hand, a cautious approach may be warranted in light of important unanswered questions about overall vaccine effectiveness, duration of protection, and adverse effects that may emerge over time. HPV vaccination has the potential for profound public health benefit if the most optimistic scenario of effectiveness is realized. No potential conflict of interest relevant to this article was reported."

Editorial
George F. Sawaya, M.D., and Karen Smith-McCune, M.D., Ph.D.
New England Journal of Medicine 5/10/07

Bonnie - this new data on the controversial HPV vaccine designed to prevent cervical cancer have raised serious questions about its efficacy, undercutting the efforts in many states to make vaccination mandatory. This is why I have told clients with daughters of this age to take a "wait and see" approach (at least 2-3 years) may be wise.

Although the Merck vaccine, called Gardasil, blocked almost 100 percent of infections by the two HPV strains it targets, it reduced the incidence of cancer precursors by only 17 percent overall.

The data also hinted that blocking the targeted strains may have opened an ecological niche that allows the flourishing of HPV strains previously considered to be minor players, partially offsetting the vaccine's protection.

The Centers for Disease Control quickly recommended that all women ages 11 to 26 receive the vaccine. The American Cancer Society seconded that recommendation, although they concluded that there was "insufficient evidence" of benefit among women aged 19 to 26 because so many had already been exposed to the virus.

Cervical cancer is caused primarily by the human papilloma virus or HPV. About 20 strains of the virus are known.
Gardasil targets only TWO of them -- called HPV-16 and HPV-18 -- that normally produce about 70 percent of the cancers. It also prevents infections with two other strains of the virus that produce about 90 percent of all genital warts.

With 18 other strains out there, are we not setting the stage for the others to become more virulent? If this occurs, then we will have just created another "dog trying to catch its tail" scenario like we have with the flu vaccine.