Study Finds HPV Vaccine Might Be Just as Effective at Lower Doses

Yahoo Contributor Network

A new study published online in the Journal of the American Medical Association's (JAMA) May 1 issue has found that giving women and girls only two doses of the human papilloma virus (HPV) vaccine may actually be just as effective as giving them three doses of it. Researchers analyzed a group of some 830 women and girls between the ages of 16 and 26 to gauge the efficacy of the vaccine at the lower doses.

Scientists working on the study took their research cues from similar vaccines for Hepatitis A and Hepatitis B, which used to be administered in three doses and are now routinely given in just two. Like those vaccines, the HPV vaccine is a protein-based vaccine, which reportedly made the researchers working on the project curious as to whether or not the number of HPV shots could be reduced as well, according to Fox News.

Here is some of the key information to emerge from this study into the efficacy of the HPV vaccine.

* The study took place in Canada. The 830 participants were followed for three years after getting their HPV vaccines, in order for scientists to be able to accurately measure whether a lowered dose provided protection against the virus for a set amount of time.

* The HPV vaccine protects against four different strains of the virus.

* For two strains of the virus, protection levels for the group that was administered two doses appeared to be as strong as it was for the group that was administered three doses. However, for the other two strains, HPV-18 and HPV-6, immune responses to the virus appeared to be lower in the group that had been administered two doses.

* One of the researchers who worked on the study, Dr. Simon R. M. Dobson of the University of British Columbia in Vancouver, told Fox News on Tuesday that scientists aren't actually sure that the lowered immune response from the group that received two doses means that the girls aren't still protected. Dobson went on to say that in the trials "there weren't enough failures" of the vaccine to determine anything absolutely, "and there wasn't a magic antibody number below which you weren't protected."

* In a separate interview, Dobson told MyHealthNewsDaily that "it's possible that two doses are going to be enough," but that at the moment "nobody would want to disadvantage a girl" by giving her less than the three doses that are currently recommended.

* Researchers who worked on the JAMA study, including Dobson, say that more study is needed before any discussions could begin on whether or not medical professionals should reduce the number of shots that a girl or woman receives as part of an HPV vaccination.

Vanessa Evans is a musician and freelance writer based in Michigan, with lifelong interest in health and nutrition issues.

View Comments