Girls are more likely to be vaccinated against the virus that causes cervical cancer when their mothers are prevention-minded, a new study suggests.

Most cases of cervical cancer are caused by persistent infection with certain strains of the human papillomavirus (HPV). The vaccine Gardasil protects against infection with the four HPV strains most likely to lead to cervical cancer, and experts recommend that girls be vaccinated before they become sexually active — as early as age 9.

In the new study, researchers looked at whether mothers' attitudes toward protecting themselves from cervical cancer influenced the likelihood of their daughters getting the HPV vaccine.

They found that girls whose mothers had recently gotten a Pap test — the routine screening test for cervical cancer — were more likely to have been vaccinated.

The finding was true regardless of race, income and education, Dr. Chun Chao and her colleagues at Kaiser Permanente in Pasadena, California, report in the American Journal of Public Health.

The results, the researchers say, suggest that targeting mothers' attitudes toward cervical-cancer prevention is one way to encourage HPV vaccination. That, Chao told Reuters Health, could be done through ads and public health campaigns that focus on women in their 30s through 50s, as well as through routine doctor visits.

"When mothers come in for Pap screening," she noted, "physicians can use that opportunity to ask about their daughter's vaccination status."

The findings are based on electronic health records from nearly 150,000 mother-daughter pairs enrolled in Kaiser Permanente Southern California. Overall, about 20,000 girls — who ranged in age from 9 to 17 — had started the three-dose course of Gardasil vaccination.

Of those girls, 41 percent completed the dosing schedule within one year, as recommended.

Chao's team found that when mothers had recently had a Pap test, their daughters were 47 percent more likely to have begun vaccination. They were also 42 percent more likely to have completed the regimen.

The fact that only a minority of girls were vaccinated as recommended shows that there is considerable room for improvement in that area, the researchers note.