A new study explored why girls from minority groups and low-income families tend to skip out on getting HPV vaccines.

Girls in these demographics often have a higher risk of contracting HPV than other groups, a University of Colorado, Denver news release reported.

"This is a population that is statistically at a higher risk of cervical cancer," study author Sean O'Leary, MD, MPH, an investigator at the Children's Outcomes Research Program, affiliated with the University of Colorado School of Medicine and Children's Hospital Colorado, said. "So we wanted to find out why they weren't getting their shots."

About 33 percent of U.S. girls complete all three shots, 28 percent of teens living below the poverty line have a full course of treatment. 

A team of researchers interviewed 41 low-income parents of girls ages 12 to 15 that spoke either Spanish or English.

Many of the English-speaking parents were worried about the safety of the relatively new vaccine. Spanish-speakers tended to have not realized their daughter needed to return for additional shots after the initial treatment due to miscommunication. Some were also worried the shot would encourage underage sex.

"The reasons low-income girls did not initiate or complete the HPV vaccination were strikingly different depending on whether their parents spoke English or Spanish," O'Leary said. "This is a safe and effective vaccine. We are seeing huge declines in HPV infection rates in the US overall and especially among those who have received the vaccine."

"They wanted definitive proof that it was necessary," he said. "The Spanish-speakers had no problems with vaccine safety. But they said their providers didn't recommend it and some feared it would encourage sexual activity."

Some parents who stopped bringing their daughters in after the first or second shot said text prompts or other types of reminders might increase their chance of completing the treatment. 

HPV is the most common sexually transmitted infection in the U.S, 75 percent of girls will contract it at some point in their lives.