How do race and ethnicity impact HPV vaccine completion rates?
The human papillomavirus (HPV) vaccine has been shown to be safe and highly effective, but vaccine coverage in the United States remains low. A recent study in Obstetrics and Gynecology looked at the role race and ethnicity play in HPV completion rates in an integrated health care system.
The retrospective cohort study included female adolescents and young women who initiated the HPV vaccine series in the Kaiser Permanente Northern California system between January 1, 2008 and December 31, 2012. Women were included if they were continuously enrolled in the Kaiser Permanente healthcare plan 1 year before and 1 year after administration of the index vaccination dose and had been given the vaccine at a Kaiser Permanente Northern California facility. Exclusion criteria were history of cervical dysplasia or neoplasia at the time of vaccine initiation as well as insufficient or lapsed health plan enrollment.
All cohort members were HPV-4 initiators. The prevalence of vaccine completion was determined for each race and ethnicity (Hispanic, black, Asian or Pacific Islander, Native American, white, or unknown) and predetermined age categories: younger adolescents (11-14 years), teens (15-17 years), and young adults (18-26 years). The researchers defined vaccine completion as receipt of at least three vaccine injections for all age groups.
After exclusions, the final study cohort consisted of 102,052 women who initiated HPV vaccination in the Kaiser Permanente Northern California system during the 4-year period of the study. The mean age at vaccine initiation was 14.5 years (SD 3.4) and the majority of females who initiated vaccination were younger adolescents (n=60,032 [58.8%]), followed by teens (n=27,668 [27.1%]), and young adults (n=14,349 [14.1%]).
A total of 41.0% of the cohort (41,847) who initiated the HPV-4 vaccine during the study period completed the series. Younger adolescents had the highest completion rates (43.4%, P = .001), followed by young adults (38.0%) and teens (37.4%). By race and ethnicity, the highest prevalence for vaccine series completion was seen among Asian and Pacific Islander patients (49.5%) and lowest among black patients (28.7%). Among Hispanic patients, 38.9% completed the vaccine series but prevalence of vaccine completion varied by level of acculturation, the process by which certain groups adopt the attitudes, values, and practice of a host society. The researchers found an inverse relationship between acculturation and vaccine completion rates, with the highest rate of vaccine completion seen in the lowest acculturated group (44.2%), compared to the moderate acculturation group (40.6%) and the high acculturation group (37.2%).
The authors believe their findings are consistent with previous investigations on HPV vaccine coverage across all racial and ethnic groups, as are their findings regarding acculturation levels. They noted that previous studies have shown improved rates of infant morbidity and mortality among low acculturated Hispanics. The authors suggest that low acculturated groups might exhibit higher adherence to medical recommendations or have social networks that encourage healthy behaviors. Earlier studies also showed that Latina women were more likely to receive an HPV vaccine recommendation from a Latin health care provider, indicating that increasing diversity and cultural awareness of health providers may decrease medial mistrust and increase HPV vaccination adherence.
The authors also noted a few strengths and limitations of their study. Among the strengths were the large, diverse cohort of females in an integrated health system and the diverse economic backgrounds of the population. Noted limitations included the retrospective design, a limited definition of Hispanic acculturation, and a lack of completion rates among boys.