HPV Vaccine Schedule: 2 Doses Just As Effective As 3, New Study Suggests

A new study from Canada suggests that two doses of the human papilloma virus (HPV) vaccine are just as effective as the recommended three doses in preventing the infection.

Researchers found that girls who received two doses of the HPV vaccine displayed a comparable immune response to the inoculation as compared to women who received three injections.

The HPV vaccine, recommended for those between the ages of 9 and 26, was found to decrease the risk of developing cervical cancer and genital warts among women, according to studies of the vaccine.

Regardless of the new findings, experts still say that women should receive the recommended dosage of three injections within six months because long-term results of the two-dose method are still unknown.

"I think this was a good start," said Dr. Simon Dobson, study researcher and pediatrician at the University of British Columbia in Vancouver.

"It's possible that two doses is going to be enough," he said, adding that more information is needed before confirmation can be made.

The study's findings also reveal that girls who received two doses of the HPV vaccine actually had a decreased immune response to two strains of the virus as compared to those who had three.

But despite this finding, Dobson says that "nobody would want to disadvantage a girl" by advising anything lower than the current recommendation.

If a two-dose schedule is deemed acceptable, it could bring some positive benefits to how the vaccine is administered.

According to the Centers for Disease Control and Prevention, the cost of one HPV vaccine dose is about $130, making it more cost-effective, especially for people in developing countries.

A two-dose protocol could also mean that more U.S. women would choose to complete the HPV vaccine series. A 2011 study found that less than one-third of U.S. women completed the vaccine series after receiving one dose, My Health News Daily reports.

Findings from the new study were based on analyzing immune responses among 830 people who were divided into three different groups: girls between the ages of 9 and 13 who received two doses of the HPV vaccine six months apart, girls of the same age who received three doses within six months, and women between the ages of 16 and 26 who received three doses over six months.

All of the study participants were given the Gardasil brand HPV vaccine.