By Stephanie Stahl

PHILADELPHIA (CBS) — Doctors hope new research on the safety of the HPV vaccine will give parents more reassurance and increase the number of teenagers being vaccinated.

The HPV vaccine prevents cancer in men and women related to sexually-transmitted infections that are widespread. It’s recommended for all teenagers, but only about half of adolescents are completing the vaccine.

The latest research published in the Journal of Pediatrics is backing up previous studies about the vaccine’s safety. It covers a three-year period when 28 million doses of the vaccine were given.

Researchers say 97% of side effects were classified as non-serious and included headaches, dizziness, fainting and irritation where the shot was given.

“The studies that were done originally were sound — the side effects are minimal and this vaccine is extremely safe,” said Dr. Jay Berger, chief medical officer at ProHEALTH Care.

It’s recommended girls and boys get two doses at 11 and 12 years old. A third dose is necessary if you start the vaccine over age 15.

Stephanie Stahl