Michele Bachmann would be pleased at this news. Recent data shows that more girls have been vaccinated with HPV vaccines such as Merck’s Gardasil over the past few years, but coverage rates are still far below levels targeted by public health officials, who have recommended the shots in hopes of thwarting the spread of cervical cancer.

Overall, just 40.5 percent of girls between the ages of 13 and 17 received at least one HPV vaccine dose, and 53.3 percent of those girls completed all three required shots, according to a new study in Pediatrics (read the abstract). The researchers from the Centers for Disease Control and Prevention analyzed data from the 2008 and 2009 National Immunization Survey-Teen, which queried more than 18,000 teens.

For those interested in a more specific yearly breakout, the percentage of girls between 13 and 17 years old who received at least one shot was 37 percent in 2008; 44.1 percent in 2009 and 48.7 percent in 2010 (see this), according to CDC data. However, this falls well short of the 80 percent target that the CDC set for teenage girls (see IID-11.4 here).

You may recall that Gardasil was approved to protect against four strains of HPV, which can lead to cervical and other cancers, in girls and women between the ages of 9 and 26 years old. Later, the vaccine was approved in boys and young men in the same age range to combat two HPV strains that can cause genital warts. GlaxoSmithKline’s Cervarix is approved for preventing HPV in females ages 9 through 25.

The results in Pediatrics are, obviously, not the most recent data, but when combined with the more recent CDC stats, the bottom-line trend only confirms the difficult battle that drugmakers have in convincing the public that their vaccines are safe and effective. Despite efforts by the CDC to promote the vaccines as useful public health tools, social conservatives fear vaccination will give teenagers a green light to premarital sex and some parents continue to worry about side effects and long-term benefits.

Gardasil, in particular, has been a flashpoint recently, thanks to the Republican presidential primary campaign in which Texas Governor and GOP candidate Rick Perry backpedaled on a 2007 decision to mandate Gardasil for school-age girls. His ties to Merck at the time became campaign fodder. And then rival candidate Michele Bachmann claimed Gardasil causes brain damage (see here and here).

At the same time, social conservatives tried to convince California Governor Jerry Brown not to sign into law a bill that removes parental consent for vaccinating children 12 and older against sexually transmitted diseases. He signed the bill last week, but not before the issue raised charges that Merck engaged in the sort of surreptitious lobbying that was conducted when Gardasil was approved in 2006 (see here).

The controversies will not make it easier for CDC officials, although Christina Dorell, the lead author of the Pediatrics study and a CDC medical epidemiologist, declined to comment on the recent events. “We’d like to achieve 80 percent for all childhood immunizations,” she tells us. “When compared to other adolescent vaccinations, the rate of percentage of increase is less. And it’s kind of flattening out for the HPV vaccine. We want to promote more education.”

The Pediatrics study also found, by the way, that factors influencing vaccination include insurance status; the mother’s age and marital status; not receiving all vaccines at public facilities; and a recommendation from a doctor or other healtcare provider, which was the factor most strongly associated with initiation. Cost may also be an issue since the shots cost a total of nearly $400.

vaccine pic thx to lulu on flickr