Doctors hope a new study gives parents more reassurance that the human papillomavirus vaccine is safe. Only about half of today's adolescents are completing the HPV vaccine, which can prevent cervical and head and neck cancers.

HPV is very common, with about 14 million people becoming infected with the sexually transmitted virus every year. Those infections can lead to cancers later in life for both men and women. Cervical cancer is the most common HPV-related cancer in women and head and neck cancers are the most common in men.

Now the latest research published in the journal Pediatrics is backing up previous studies about the vaccine's safety. Dr. Jay Berger is chief medical officer at ProHEALTH Care.

 "The studies that were done originally were sound and the side effects are minimal and this vaccine is extremely safe," he said.

Investigators reviewed reports over a three-year period when 28 million doses of the vaccine were given. According to research in the journal Pediatrics, 97% of side effects were classified as non-serious and included headache, dizziness, fainting, and irritation where the shot was given.

Another recent study shows the vaccine can prevent about 92% of HPV-related cancers.

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

"We need to get the vaccine in way before we are even thinking about sexual exposure," Dr. Berger said. He says the body also has a better response when the vaccine is given at a younger age.

Doctors hope the latest science will encourage more parents to protect their children.