The study, published online in the journal Vaccine, examined the association between geographic region and HPV vaccine uptake and completion rates among women ages18-26 in 12 states. It is the first study of its kind to include initiation and completion rates and assess data across multiple years.

The researchers used data collected between 2008 and 2010 from the Behavioral Risk Factor Surveillance System, the world's largest ongoing health survey, from 12 states representing four distinct regions: the Northeast (Connecticut, Massachusetts, Pennsylvania, Rhode Island); the Midwest (Kansas, Minnesota, Nebraska); the West (Wyoming); and the South (Delaware, Oklahoma, Texas, West Virginia).

The researchers found:

• Nationwide, an average of 28 percent of women reported initiating the vaccine and 17 percent reported completing the three-dose series over the three-year period. When examined by region: -- Over the three-year period, HPV vaccine initiation and completion rates were 37.2 percent and 23.1 percent in the Northeast; 28.7 percent and 19.3 percent in the Midwest/West; and 14 percent and 6 percent in the South; -- Initiation and completion rates were consistently lowest in the South; -- Initiation rate in the Northeast was 20.8 percent in 2008 and 44.1 percent in 2010; -- Initiation rate in the Midwest/West was 36.4 percent in 2008 and 29.2 percent in 2010; and -- Initiation rate in the South was 14 percent in 2008 and 22.5 percent in 2010.
• Despite the increase in uptake over the period of time, the South's vaccine initiation rate in 2010 remained very low (22.5 percent) compared with the Northeast (44.1 percent).
• Adjusted for age, race/ethnicity, marital status, education, income, health coverage and routine medical check-ups/flu vaccines, women living in the South were still less likely to initiate or complete the HPV vaccine series.
• White women were more likely to initiate and complete the vaccine series compared with other races/ethnicities.

"If a lower rate of HPV vaccine uptake in the South persists, it could contribute to the national burden of cervical cancer in the long run," says Dr. Abbey Berenson, professor in the department of obstetrics and gynecology and director of UTMB's Center for Interdisciplinary Research in Women's Health and contributor to this study.

"We need more physician referrals, public financing for vaccine programs and educational interventions to improve HPV vaccine uptake if we want to lower rates of HPV-related diseases," said Berenson.

An estimated 79 million Americans are currently infected with HPV, and most sexually active persons will contract at least one type of HPV at some point in their lives. The virus is responsible for nearly all cases of cervical cancer, which each year kills more than 4,000 American women -- half of whom are estimated to live in the South. HPV is also associated with genital warts and vulvar, vaginal, penile, anal and oropharyngeal cancers.

The researchers believe regional disparities could be due to a confluence of several factors, including differences in income, education and insurance coverage. "We need to examine whether regional or state level policies contribute to these variations, especially if these policies are hindering patients from learning about or receiving the vaccine," says lead author Dr. Mahbubur Rahman, associate professor of obstetrics and gynecology at UTMB.

This study adds to previous literature and builds on a growing body of knowledge at UTMB regarding HPV uptake. Earlier studies led by Berenson have focused on completion rates among females ages 9-27 and differences in parents' willingness to vaccinate their sons and daughters.