Tuesday, February 13, 2007

HPV and Sex

I must admit, my libertarian sensitivites get a bit out of order when I hear the government mandate anything, but this might be a legitimate public health consideration:

From The Economist print edition: A new vaccine sparks controversy

“THE governor's action seems to signify that God's moral law regarding sex outside of marriage can be transgressed without consequence.” Those words came this week from Rick Scarborough of Vision America, a Christian lobbying group. The US Pastor Council and various Republican politicians have piled in too.

Usually, this sort of right-wing animosity is reserved for the likes of Hillary Clinton, but this week's attack was on one of the Christian right's favourite sons: Rick Perry, the deeply religious Republican governor of Texas. His offence? Promoting the use of a highly effective new vaccine that is sure to save many women from a nasty form of cancer. But to some people, it is tantamount to encouraging promiscuity.

On February 2nd Mr Perry bypassed the state legislature and mandated vaccination against the human papilloma virus (HPV). His order would affect all girls entering sixth grade (at about 11) unless their parents opt out in writing. Perhaps 20m Americans carry this virus, making it one of the most common sexually transmitted diseases in the country. Most strains are harmless, but a few can lead to cervical cancer, the second most deadly form of cancer in women.

Merck, a drugs giant, won federal approval for its HPV vaccine last year and has been lobbying for its adoption. California, South Dakota, New Hampshire and other states now make it available. Virginia, Maryland and the District of Columbia are considering the matter, while Washington state this week announced a voluntary scheme. But no state has mandated its use until now.

Why did Mr Perry do it? Some sneerers have noted that his former chief of staff is now a lobbyist for Merck. Others think that the wily governor is distancing himself from his conservative base so that he can make a plausible vice-presidential candidate in 2008. But there is another explanation: that he had the courage to make a politically difficult but sound policy decision. As he said this week: “If the medical community developed a vaccine for lung cancer,” he asked, “would the same critics oppose it, claiming it would encourage smoking?”

Time will tell if this really leads to substantial increase in teen sex. The differential adoption of the vaccine by State will provide a nice natural experiment. My guess is the results might be similar to this paper by Thomas Stratmann.

Laws requiring minors to seek parental consent or to notify a parent prior to obtaining an abortion raise the cost of risky sex for teenagers. Assuming choices to engage in risky sex are made rationally, parental involvement laws should lead to less risky sex among teens, either because of a reduction of sexual activity altogether or because teens will be more fastidious in the use of birth control ex ante. Using gonorrhea rates among older women to control for unobserved heterogeneity across states, our results indicate that the enactment of parental involvement laws significantly reduces risky sexual activity among teenage girls. We estimate reductions in gonorrhea rates of 20 percent for Hispanics and 12 percent for whites. While we find a relatively small reduction in rates for black girls, it is not statistically significant. We speculate that the racial heterogeneity has to do with differences in family structure across races.

No comments: