Dr. Berenson's research interests involve the study of women's health and fertility issues. Currently, she is studying the quadrivalent human papillomavirus (HPV) vaccine that requires three injections spaced 1 month and 6 months after the first vaccine, and is intended for use by adolescents and adults 9-26 years of age. Research based on national-level interviews indicates that the prevalence of teens 11-17 and 18-26 year olds who are initiating and completing the vaccine series has been increasing. However, prevalence estimates are slow to reflect changes in incidence of completion due to aggregation of rates across age groups. Therefore, researchers at UTMB undertook a study to examine changes in completion among new initiators across time. Dr. Berenson's group found that since the vaccine was introduced, the proportion of females who complete the vaccine series has declined among initiators. Although the overall odds of completing were higher among 9-12 and 13-18 year olds, the likelihood of completing the series decreased faster in these groups than among older women across time. This was an important finding because the vaccine is most effective if it is administered to patients before they are exposed to the virus, and thus the goal is to completely vaccinate females before sexual debut. This research indicates that doctors may need to make greater efforts to contact their patients once they have initiated the series and encourage them to complete the vaccine series.