September 15, 2011


HPV Vaccine's Tricky Ethics: Rick Perry may have been wrong to try forcing HPV vaccinations in Texas, and Michele Bachmann was definitely wrong when she said HPV causes mental retardation, but the issue of mandating vaccinations can be ethically tricky (Sharon Begley, 9/14/11, Daily Beast)

First, the basics. There are two FDA-approved HPV vaccines. Gardasil got the OK for use in girls and young women ages 9 through 26 for the prevention of cervical, vulvar, vaginal, and anal cancers caused by two forms of HPV, called types 16 and 18. It also prevents genital warts caused by HPV strains 6 and 11, and in 2009 was FDA-approved for that purpose in males as well. Strains 16 and 18 cause 70 percent of cervical cancers, while 6 and 11 cause 90 percent of the cases of genital warts. These four strains also cause the benign cervical changes that result in abnormal Pap tests. The FDA approved a second vaccine, Cervarix, from GlaxoSmithKline, against cervical cancer (but not genital warts) in October 2009, for girls and women ages 10 to 25. The U.S. Centers for Disease Control and Prevention recommends HPV vaccination of girls at age 11 or 12, and "catch-up vaccination" for those 13 through 26. The vaccines, which consist of series of three intramuscular shots given over six months, are 97 to 100 percent effective in preventing HPV infection.

Age 11 may seem early to get a vaccine against a virus that can be acquired only through sexual activity. (The CDC estimates that 20 million American men and women ages 14 to 59 are infected with at least one type of HPV, including more than 25 percent of women 14 to 59.) The early age reflects the fact that the vaccines prevent HPV infection only if you have not been exposed to the virus, explains pediatrician and infectious-disease expert Joseph Bocchini of Louisiana State University, so the inoculation is most likely to be effective before a girl is sexually active. "We don't know why that is," he says. "The vaccine causes you to develop a strong antibody response to the virus, so that if you are subsequently exposed you do not become infected. But if you are already infected, the vaccine does not change the course or outcome of the infection." Some 70 percent of females will be infected with HPV within five years of becoming sexually active. On the other hand, if you are not sexually active and were never exposed to HPV, the vaccine should work at any age. [...]

The need for caution was made clear in a report on the adverse effects of vaccines by the Institute of Medicine, released last month. Its chapter on HPV vaccines examines 13 kinds of reported problems, from multiple sclerosis to Guillain-Barre syndrome. In 12 cases it found the evidence "inadequate" to link the vaccine to the illness, mostly because only anecdotes and not rigorous research suggest a connection. Only anaphylaxis--an extreme allergic reaction--seems to be caused by the vaccine in a small percentage of cases, which reflects the fact that some people are allergic to some components of all vaccines. As for mental retardation, this week the American Academy of Pediatrics weighed in: AAP "would like to correct false statements made in the Republican presidential campaign that HPV vaccine is dangerous and can cause mental retardation," it said in a statement. "There is absolutely no scientific validity to this statement. Since the vaccine has been introduced, more than 35 million doses have been administered, and it has an excellent safety record."

Posted by at September 15, 2011 5:24 AM

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