Proximity to safety-net clinics and HPV vaccine uptake among low-income, ethnic minority girls

Abstract

Purpose

Human Papillomavirus (HPV) vaccine uptake remains low. Although publicly funded programs provide free or low cost vaccines to low-income children, barriers aside from cost may prevent disadvantaged girls from getting vaccinated. Prior studies have shown distance to health care as a potential barrier to utilizing pediatric preventive services. This study examines whether HPV vaccines are geographically accessible for low-income girls in Los Angeles County and whether proximity to safety-net clinics is associated with vaccine initiation.

Methods

Interviews were conducted in multiple languages with largely immigrant, low-income mothers of girls ages 9 to 18 via a county health hotline to assess uptake and correlates of uptake. Addresses of respondents and safety-net clinics that provide the HPV vaccine for free or low cost were geo-coded and linked to create measures of geographic proximity. Logistic regression models were estimated for each proximity measure on HPV vaccine initiation while controlling for other factors.

Results

On average, 83% of the 468 girls had at least one clinic within 3-miles of their residence. The average travel time on public transportation to the nearest clinic among all girls was 21 min. Average proximity to clinics differed significantly by race/ethnicity. Latinas had both the shortest travel distances (2.2 miles) and public transportation times (16 min) compared to other racial/ethnic groups. The overall HPV vaccine initiation rate was 25%. Increased proximity to the nearest clinic was not significantly associated with initiation. By contrast, daughter's age and insurance status were significantly associated with increased uptake.

Conclusions

This study is among the first to examine geographic access to HPV vaccines for underserved girls. Although the majority of girls live in close proximity to safety-net vaccination services, rates of initiation were low. Expanding clinic outreach in this urban area is likely more important than increasing geographic access to the vaccine for this population.

Introduction

Low income, ethnic minority, and immigrant women experience a higher burden of cervical cancer in the United States (U.S.) [1], [2]. In Los Angeles County (LAC), cervical cancer incidence is significantly higher than the national average (12.1 per 100,000 vs. 8.1 per 100,000) [3], with Latina women having the highest rates (18.1 per 100,000) among all ethnic groups [4].

Wide-spread adoption of HPV vaccines has the potential to substantially reduce future cases of cervical cancer as well as other HPV-related cancers and genital warts [5]. Both the bivalent and quadrivalent vaccines are recommended for routine use among girls ages 11 to12 years old and approved for use among girls as young as 9 and up to age 26 [6]. Low-income children who qualify for the federally funded Vaccines for Children (VFC) program can access the vaccines for free or low cost via VFC providers [7].

Currently, adolescent HPV vaccination rates remain low in the U.S. Recent national data revealed only 53% of adolescent girls initiated the HPV vaccine and 35% completed the 3-dose series in 2011 [8]. These rates are much lower than uptake rates for other adolescent vaccines [9]. Unless the vaccine is adopted by all subgroups, including girls that are most at risk for cervical cancer, disparities will likely remain. Existing research on HPV vaccine uptake has focused mainly on individual level factors, including demographic characteristics, vaccine knowledge [10], [11] and acceptability [12], [13]. Recent studies assessing barriers to uptake among disadvantaged groups indicate that less educated, low-income and ethnic minority parents are less likely to have heard of the HPV vaccines or have vaccinated daughters [14], [15].

Few studies have explored geographic access to vaccination services, especially among disadvantaged girls, as a potential barrier to HPV vaccine initiation. Geographic access to care, defined as the relationship between the location of health care providers and the location of clients [16], has been shown to impact the utilization of health services, including HIV testing, asthma management, breast cancer screening, and childhood immunizations [17], [18], [19], [20]. Importantly, a recent study found that low-income, urban children living closer to pediatricians were more likely to be up to date with childhood vaccinations [17]. In a similar study, asthmatic children with increased geographic access (i.e. proximity) to providers had better longitudinal asthma management [20]. In response to reducing geographic barriers to primary care services, local health departments and individual health care organizations across the country have implemented mobile van clinics as a strategy to increase access to underserved communities [21], [22], [23]. A prior study, focused on understanding childhood immunizations in states and urban areas, cited mobile health vans and improving clinic hours as strategies for increasing uptake [24]. Despite the growing evidence that distance to vaccination services may be a plausible barrier to uptake, little is known about whether safety-net immunization services are geographically accessible to disadvantaged communities that can benefit most from HPV vaccines.

This study examines the proximity of county operated and affiliated safety-net immunization clinics to a sample of low-income, ethnic minority girls in Los Angeles County who are age eligible for HPV vaccination. The study also assesses the extent to which HPV vaccine uptake is associated with proximity to safety-net immunization clinics.