Thursday, January 26, 2012

Talking to Your Girls: The Best Vaccine of All

In a previous posting, I noted that there are almost no studies looking at whether giving the human papillomavirus (HPV) vaccine to adolescents increases unsafe sexual behavior -- what some call a passport to promiscuity for girls and a license to drill for boys.  Although there are still no studies looking at behavior post-vaccine, the Archives of Pediatric and Adolescent Medicine just published a study on the attitudes and beliefs of girls who got the HPV shot.
The authors asked the girls (ages 13-21) to agree or disagree with statements like, "After getting the shot against HPV, I am less worried about getting a sexually transmitted disease other than HPV," and "After getting the shot against HPV, I think that condom use (or having fewer sexual partners) is less necessary."

First, the good news:  Only 4% of the girls felt less of a need to practice safe sex because of the vaccine.  The investigators then looked at what factors were associated with this belief.  Some risk factors were predictable, but a few were surprising.  A lower perceived need for safe sex was associated with:
  • Lower knowledge about HPV and the vaccine
  • Lack of condom use at last intercourse
  • Lack of maternal communication about the HPV vaccine
  • Teacher or physician serving as the source of HPV vaccination information
The last one threw me for a loop.  Surely the most reliable information about the vaccine and STDs comes from doctors and sex education teachers?  The problem is that even if they are dispensing appropriate advice (which may or may not be a correct assumption) , they may not be doing so in a way that's understandable to teens and their mothers.  On the flip side, it looks like moms can have a positive impact in their daughters' behavior, particularly if they talk to them about the limitations of the vaccine, including its lack of protection against some HPV strains, other STDs and pregnancy.

Though very few girls agreed that the vaccine would allow them to have more unprotected sex, survey answers don't necessarily predict behavior.  Even before the vaccine, over half of the adolescents in this clinic were sexually experienced, and most were not using condoms reliably.  It's doubtful that the vaccine will decrease the rate of unsafe sexual practices, unless it's accompanied with appropriate counseling.

So does this mean we shouldn't be vaccinating our daughters against, because of the theoretical increased risk of unsafe behavior?  Of course not.  The advent of effective antiretroviral therapy for HIV in the late 1990's was accompanied by an increase in the rate of unprotected sex, and subsequent gonorrhea and syphilis epidemics, in gay and bisexual men.*  Yet it would be completely unethical to withhold effective drug therapy because of its unintended behavioral consequences.  No, it simply means that doctors and, more importantly, parents have our work cut out for us when it comes to educating our kids.

*Despite the increases in other STDs in the San Francisco Bay Area, there was no increase in the HIV incidence in gay men during this time period.  The theory is that HIV-positive men had unsafe sex only with HIV-positive men, and HIV-negative only with HIV-negative.

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