Experts say the findings are surprising and troublesome, because the vaccine is not associated with any serious negative side effects.
HPV manifests in over 100 different strains - some of which produce genital and anal warts. In many people, the immune system eliminates the virus quickly from the body. However, persistent HPV strains can eventually cause cervical cancer in some women.
The CDC recommends that all females ages 11 and 12 receive the HPV vaccine and that adolescents and young women up to age 26 receive a "catch-up" vaccine.
The current study revealed that between 2008 and 2010, a rising number of girls were vaccinated against HPV in the U.S. The percentage of 13 to 17 year olds who were not current with their immunizations dropped from 84 percent to 75 percent.
The researchers examined the 2008-2010 National Immunization Survey of Teens to analyze why parents did not keep their teenagers current on their recommended vaccines - and how their reasons for not doing so have changed over the years.
They found that the main reasons parents did not get the HPV vaccine for their daughters were:
- safety issues/side effects
- not appropriate age
- not sexually active
Parental concerns about safety rose each year, from 4.5 percent in 2008 to 16.4 percent in 2010. Parental intent not to vaccinate for HPV also rose from 39.8 percent in 2008 to 43.9 percent in 2010.
Parents who participated in the study were also asked about two other types of vaccines for teenagers: the "Tdap" against tetanus, diphtheria and whooping cough; and the "MCV4" vaccine against bacterial meningitis.
For these two vaccines, less than one percent of parents reported any safety concerns.
Reported side effects associated with the HPV vaccine are the same as other vaccines:
- pain at injection site
- mild fever
A national poll conducted last year in the U.S. found that most parents believe parental consent should be required to obtain the HPV vaccine for kids ages 12 to 17 years.
The study authors concluded that regardless of doctor recommendations, parental refusal to immunize their kids against diseases that are preventable by vaccine, such as HPV, is a growing and alarming trend. They call for doctors to have more in-depth conversations with parents about vaccine safety and effectiveness to improve future immunization rates.
Written by Kelly Fitzgerald