Behavioral and social drivers of COVID-19 vaccination initiation in the US: a longitudinal study March─ October 2021.

Many studies have examined behavioral and social drivers of COVID-19 vaccination initiation, but few have examined these drivers longitudinally. We sought to identify the drivers of COVID-19 vaccination initiation using the Behavioral and Social Drivers of Vaccination (BeSD) Framework. Participants were a nationally-representative sample of 1,563 US adults who had not received a COVID-19 vaccine by baseline. Participants took surveys online at baseline (spring 2021) and follow-up (fall 2021). The surveys assessed variables from BeSD Framework domains (i.e., thinking and feeling, social processes, and practical issues), COVID-19 vaccination initiation, and demographics at baseline and follow-up. Between baseline and follow-up, 65% of respondents reported initiating COVID-19 vaccination. Vaccination intent increased from baseline to follow-up (p < .01). Higher vaccine confidence, more positive social norms towards vaccination, and receiving vaccine recommendations at baseline predicted subsequent COVID-19 vaccine initiation (all p < .01). Among factors assessed at follow-up, social responsibility and vaccine requirements had the greatest associations with vaccine initiation (all p < .01). Baseline vaccine confidence, social norms, and vaccination recommendations were associated with subsequent vaccine initiation, all of which could be useful targets for behavioral interventions. Furthermore, interventions that highlight social responsibility to vaccinate or promote vaccination requirements could also be beneficial.

Adherence to ACIP Recommendation for Human Papillomavirus Vaccine Among US Adolescent Girls.

The objective of this study was to examine correlates of human papillomavirus (HPV) vaccine use according to Advisory Committee on Immunization Practices (ACIP)'s recommendations among US adolescent girls. We used National Immunization Survey of Teens 2013 data. Based on provider-verified (n = 9403) information, 57.3, 39.1 and 19.0 % of adolescent girls, initiated, completed and completed the HPV vaccine according to ACIP's recommendation (by age 12), respectively. Hispanic race/ethnicity, a physician recommendation for HPV vaccine and ≥1 influenza vaccine in the past 3 years were all associated with a higher likelihood of compliance with ACIP's recommendation. Girls from a larger family and those whose immunization provider was a STD/school/teen clinic were less likely to receive the vaccine at the recommended age compared to a girl raised in a smaller sized family and received immunization from a hospital facility, respectively. Only one-fifth of 13-17 yo girls receive the HPV vaccine by age 12 as recommended by ACIP. Physician visits and influenza vaccination settings are opportunities to improve vaccine series completion at the recommended age.

A human papillomavirus vaccination program for low-income postpartum women.

BACKGROUND: Effective interventions are needed to address the low rate of human papillomavirus (HPV) vaccination in the United States, particularly among girls and women 16-26 years old. Counseling and offering the vaccine to postpartum patients could be an effective strategy to increase uptake among young women who did not complete the 3-dose series at an earlier age. OBJECTIVE: The purpose of this evaluation was to assess the effectiveness of a multicomponent program designed for postpartum women that used patient navigators (PNs) and reminders for follow-up visits to improve uptake and completion of the HPV vaccine series. STUDY DESIGN: As part of standard care, patients ≤26 years of age from Galveston County, Texas, who delivered an infant from November 2012 through June 2014 at a public hospital were counseled and offered the HPV vaccine postpartum. PNs assisted with scheduling follow-up injections during postpartum or well-child visits. A program evaluation was conducted after 20 months. RESULTS: Of 1038 patients approached, only 161 (15.5%) had previously completed the vaccine series. Of the 877 patients who had not completed the series, 661 (75.4%) received at least 1 dose postpartum, with 575 patients receiving their first dose and 86 receiving their second or third doses. By April 2015, initiation rates had increased as a result of this program from 25.4% before the program was initiated to 80.8% and completion rates from 15.5-65.1%. Missed appointments for injections were less likely among those who received text message reminders and more likely among those with ≥2 prior pregnancies. Those who were Hispanic or had received an influenza vaccination in the last year were more likely to initiate and complete the series through this program. Patients who missed ≥1 follow-up appointments were less likely to complete the vaccine series. CONCLUSION: Offering the HPV vaccine postpartum dramatically increased initiation rates among postpartum patients. PN and text messages ensured that a high percentage completed all 3 doses.

Recommend, but also Discuss: Different Patterns of Physician-Perceived Barriers to Discussing HPV Vaccination and Their Association with Vaccine Administration in 11-12 Year-Old Girls.

Objectives We examined variation in primary care physicians' (PCPs') perceptions of barriers to physician-initiated discussion of HPV vaccination, and how this is associated with the rates at which they discuss, initiate and continue to administer vaccination with 11-12 year-old girls. Methods We surveyed 301 PCPs using systematic random sampling. PCP variation in perceived barriers to discussing HPV vaccination was modeled using latent class analysis (LCA). The distinct PCP groups identified were compared with each other using three iterative logistic regression models to predict the likelihood of initiating vaccine discussion and the reported percentages of 11-12 year-old patients who initiated HPV vaccination and received follow-up shots. Results LCA revealed three groups of PCPs who perceived major, moderately significant and relatively minor barriers (17.9, 41.9 and 40.2 % of respondents, respectively). Pediatricians, PCPs who were female, had minority racial/ethnic status and who perceived only minor barriers had significantly higher odds of initiating discussion. PCPs were more likely to initiate HPV vaccination if they had initiated discussion and perceived minor or moderate communication barriers. Increased likelihood to administer follow-up HPV vaccine was associated with having initiated discussion, perceiving only minor barriers and working outside Deep South states, but not with having initiated vaccination. Conclusions for Practice PCPs who discuss HPV vaccination with girls aged 11-12 and their mothers are more likely to start and sustain vaccine administration. However, different PCPs perceive barriers to discussion in different ways. Interventions tailored to different groups of PCPs should assist them in overcoming barriers to discussing their recommendations when necessary.

Providers' beliefs about the effectiveness of the HPV vaccine in preventing cancer and their recommended age groups for vaccination: Findings from a provider survey, 2012.

BACKGROUND: The human papillomavirus (HPV) vaccine was recommended in 2007 by the Advisory Committee on Immunization Practices (ACIP) to preadolescent and adolescent girls. Vaccination initiation was recommended at age 11-12 years with the option to start at age 9. Catchup vaccination was recommended to females aged 13-26 previously not vaccinated. However, vaccination coverage remains low. Studies show that the HPV vaccine can prevent cervical, vulvar, vaginal, anal and some oropharyngeal cancers and that provider recommendation of vaccines can improve low vaccination rates. METHODS: Using data from 2012 DocStyles, an annual, web-based survey of U.S. healthcare professionals including physicians and nurse practitioners (n=1753), we examined providers' knowledge about the effectiveness of the HPV vaccine in preventing cancer and their vaccine recommendation to all age-eligible females (9-26 years). Descriptive statistics and Chi-square tests were used to assess differences across specialties. RESULTS: Knowledge about HPV vaccine effectiveness in preventing cervical cancer was highly prevalent (96.9%), but less so for anal, vaginal, vulvar and oropharyngeal cancers. Only 14.5% of providers recommended the vaccine to all age-eligible females and 20.2% recommended it to females aged 11-26 years. Knowledge assessment of cancers associated with HPV and vaccination recommendations varied significantly among providers (p<0.01). Providers more frequently recommended the vaccine to girls older than 11-12 years. CONCLUSIONS: Improving providers' knowledge about HPV-associated cancers and the age for vaccination initiation, communicating messages focusing on the vaccine safety and benefits in cancer prevention and on the importance of its delivery prior to sexual onset, may improve HPV vaccine coverage.

When the market got the first dose: Stock volatility and vaccination campaign in COVID-19 period.

During the COVID-19 pandemic, the news of clinical trials for vaccines and mass vaccinations have brought renewed optimism for stabilizing the economy and financial markets. However, the mental stress of investors or doubt about the effectiveness of government policies to cope with economic disruptions has caused stock market volatility. We investigate the significance of the vaccination rate in alleviating the global stock market volatility which is measured by the GJR-GARCH model. We discover that a higher vaccine initiation rate has a positive effect on global stock markets, especially in developed countries and areas with higher rates than their average. Our findings remain reliable even when using different projected volatility models and other estimates of the main independent variables. Mass immunization also implies that governments will not have to take extreme measures to handle the pandemic, which alleviates investor worries about compliance and the prolonged effects of COVID-19. Our research indicates that global stock markets are providing insight into the economic value of the development of COVID-19 vaccines, even before public vaccinations start.

Does HPV vaccination initiation at age 9, improve HPV initiation and vaccine series completion rates by age 13?

Vaccination for Human Papillomavirus (HPV) is important to reduce rates of cervical and oropharyngeal cancer. We aimed to evaluate if a program to initiate HPV vaccination at 9 years improved initiation and completion rates by 13 years of age. Data on empaneled patients aged 9-13 years from January 1, 2021 to August 30, 2022 were abstracted from the electronic health record. Primary outcome measures included HPV vaccination initiation and series completion by 13 years of age. The secondary outcome measure was missed opportunities for HPV vaccination. In total, 25,888 patients were included (12,433 pre-intervention, and 13,455 post-intervention). The percentage of patients aged 9-13 with an in-person visit who received at least 1 dose of HPV vaccine increased from 30% pre-intervention to 43% post-intervention. The percentage of patients who received 2 doses of vaccine increased from 19.3% pre-intervention to 42.7% post-intervention. For the overall population seen in-person, initiation of HPV vaccination by age 13 years increased from 42% to 54%. HPV completion increased as well (13% to 18%). HPV vaccination initiation at 9 years of age may be an acceptable and effective approach to improving vaccination rates.

Facilitators and Barriers of HPV Vaccine Acceptance, Initiation, and Completion among LGBTQ Community in the U.S.: A Systematic Review.

Objective: This study aims to identify facilitators and barriers of Human Papillomavirus (HPV) vaccine acceptance, initiation, and completion among LGBTQ (lesbian, gay, bisexual, trans, and queer) individuals. Method: A systematic review of qualitative and quantitative studies on HPV vaccine acceptance, initiation, and completion from 2006 to June 15, 2020 was performed in each database. Results: Twenty-six studies focusing on HPV vaccination among LGBTQ individuals were reviewed. Conclusions: Knowledge of HPV vaccine and healthcare providers' recommendations were identified as facilitators to receive HPV vaccinate, while high co-pay cost and concerns of the effectiveness and safety were identified as barriers.

Association between Sexual Activity and Human Papillomavirus (HPV) Vaccine Initiation and Completion among College Students.

HPV vaccination is most effective if received before initiation of sexual activity. Previous studies suggested that young adult women who were not sexually active were not interested in receiving the vaccine because they did not think it was necessary. Whether this misperception is still prevalent today-and also shared by men-is unknown. This study examined whether sexual activity was associated with HPV vaccine uptake (initiation and completion) among university students. A cross-sectional study was conducted between February and May 2021 among students (n = 951) at a public Midwestern University. Sexual activity was categorized as "never" or "ever" had oral and/or vaginal sex. Outcome variables were HPV vaccine initiation, defined as receipt of ≥1 dose, and completion, defined as receipt of ≥3 doses. Multivariable logistic regression models estimated the association between sexual activity and HPV vaccine uptake, adjusting for sociodemographic factors. Approximately 18% of students reported never engaging in sexual activity. Overall, 45.5% initiated the HPV vaccine, and 16.5% completed the vaccine series. After adjusting for covariates, compared to students that reported never engaging in sexual activity, those that had ever engaged in sexual activity were more likely to have initiated the vaccine series (aOR = 2.06, 95% CI: 1.34-3.17); however, no difference was observed for completion. HPV vaccination was low; sexually naïve students were less likely to initiate the HPV vaccine. Since sexually naïve students may benefit from receiving the HPV vaccination, targeted interventions should be implemented towards this population to help increase vaccination rates and prevent HPV-associated diseases.

HPV vaccination initiation among white, black and Middle East North African (MENA) males.

Objectives: US males initiate HPV vaccination at older ages than females and currently have low population coverage. We aim to describe the prevalence and predictors of HPV vaccination initiation among males of White, Black, and Middle-Eastern/North-African (MENA) descent in southeast Michigan. Methods: We conducted three community-based surveys in 2019 that provided primary data via self report. Using population weights and multivariate modeling, we measured the prevalence and predictors of HPV vaccine initiation in each race/ethnicity of men (age 18-34 years) analyzed. Results: The vaccine initiation rates were 44.5 % (95 % CI: 44.4, 44.6) for White men, 46.2 % (46.0, 46.4) for Black men, and 23.2 % (22.8, 23.6) for MENA men, (p < 0.001). Being a student, compared to unemployed or disabled, was significantly associated with HPV vaccine initiation across all three races/ethnicities. Married men of any race/ethnicity were unlikely to be vaccinated. MENA men born in the US and having some college education were also more likely to initiate HPV vaccination. Conclusions: White, Black, and MENA men are not vaccinated in accord with Healthy (Healthy People 2030, 2022) goals. Each race/ethnicity has different predictors of vaccination.

Factors influencing Human papillomavirus (HPV) vaccination series completion in Mississippi Medicaid.

PURPOSE: To identify factors associated with Human Papillomavirus (HPV) vaccine series completion among vaccine initiators in Mississippi Medicaid. METHODS: 2013-2018 Mississippi Medicaid administrative claims data were analyzed. Female and male beneficiaries aged 9 to 26 years who initiated HPV vaccination in the identification period were assessed for completion of age-appropriate number of recommended doses within a period of 12 months. Sex-stratified multivariable logistic regression was used to examine factors associated with HPV vaccine series completion in the study sample. RESULTS: A total of 18,110 female and 18,186 male beneficiaries initiated HPV vaccine between January 1, 2014 and June 30, 2017. Most of the initiators belonged to ages 11 to 12 years, African American race, managed care plans and Central Mississippi public health region. The vaccine series completion rate was 34% for females and 30% for males. Younger age at initiation was a significant predictor of vaccine series completion in both sexes. Specifically, initiators in age groups 9 to 10 and 11 to 12 years, respectively, had greater odds of completion, while initiators aged 15 to 26 years had lower odds of completion compared to initiators aged 13 to 14 years. Female and male beneficiaries in managed care plans (vs. fee-for-service) and of African American race (vs. Caucasians) had lower odds of completing the vaccine series. Female and male beneficiaries who initiated HPV vaccine series with a pediatrician had the highest completion rates. CONCLUSION: HPV vaccination series completion rate in Mississippi Medicaid was suboptimal despite the high HPV-related cancer incidence in the state. HPV vaccine series completion is influenced by various sociodemographic factors. There is a need for robust education and public health programs to encourage completion of recommended doses.

Human Papillomavirus Vaccine Coverage and Prevalence of Missed Opportunities for Vaccination in an Integrated Healthcare System.

BACKGROUND: Human papillomavirus (HPV) vaccination has been recommended in the United States for female and male adolescents since 2006 and 2011, respectively. Coverage rates are lower than those for other adolescent vaccines. The objective of this study was to evaluate an assessment and feedback intervention designed to increase HPV vaccination coverage and quantify missed opportunities for HPV vaccine initiation at preventive care visits. METHODS: We examined changes in HPV vaccination coverage and missed opportunities within the adolescent (11-17 years) population at 9 Oregon-based Kaiser Permanente Northwest outpatient clinics after an assessment and feedback intervention. Quarterly coverage rates were calculated for the adolescent populations at the clinics, according to age group (11-12 and 13-17 years), sex, and department (Pediatrics and Family Medicine). Comparison coverage assessments were calculated at 3 nonintervention (control) clinics. Missed opportunities for HPV vaccine initiation, defined as preventive care visits in which a patient eligible for HPV dose 1 remained unvaccinated, were examined according to sex and age group. RESULTS: An average of 29,021 adolescents were included in coverage assessments. Before the intervention, 1-dose and 3-dose quarterly coverage rates were increasing at intervention as well as at control clinics in both age groups. Postimplementation quarterly trends in 1-dose or 3-dose coverage did not differ significantly between intervention and control clinics for either age group. One-dose coverage rates among adolescents with Pediatrics providers were significantly higher than those with Family Medicine providers (56% vs 41% for 11- to 12-year-old and 82% vs 69% for 13- to 17-year-old girls; 55% vs 40% for 11- to 12-year-old and 78% vs 62% for 13- to 17-year-old boys). CONCLUSIONS: No significant differences in HPV vaccine coverage were identified at intervention clinics. However, coverage rates were increasing before the start of the intervention and might have been influenced by ongoing health system best practices. HPV vaccine coverage rates varied significantly according to department, which could allow for targeted improvement opportunities.

Assessing university students' sexual risk behaviors as predictors of human papillomavirus (HPV) vaccine uptake behavior.

OBJECTIVES: There exists a significant gap in vaccine coverage of the human papillomavirus (HPV) among college-aged students. This study assessed sexual risk-taking behavior among university students and analyzed predictors of HPV vaccine initiation and completion in this population. MATERIALS AND METHODS: Data (n = 746) were from an anonymous online, cross-sectional survey distributed to university students, between the ages of 19-26 years, at a private Midwestern university. Both chi-square and multivariable logistics regression models estimated the association between sociodemographic characteristics and sexual risk factors (including number of vaginal sexual partners, number of oral sexual partners, initiation of oral sex, and initiation of vaginal sex), with HPV vaccine initiation and completion. RESULTS: A significant number of participants (40%) had not received a single dose of the HPV vaccine series. Of those who initiated the series, more than half (51%) did not achieve completion. Additionally, a greater number of participants have had multiple (4 or more) oral sexual partners than vaginal sexual partners (25.7% vs. 20.3%). After adjusting for covariates, it was found that sexual risk factors were not significantly associated with HPV vaccine initiation or completion. CONCLUSION: HPV vaccine initiation and completion rates are suboptimal among university students. High levels of sexual-risk taking behaviors associated with HPV infection persist, yet are not significant predictors of HPV vaccine behaviors in this age group. To increase uptake among 18-26-year-old students, future public health interventions should focus on HPV vaccine education and uptake across the entire population, irrespective of sexual risk profile.

Missed opportunities for catch-up human papillomavirus vaccination among university undergraduates: Identifying health decision-making behaviors and uptake barriers.

BACKGROUND: Suboptimal adolescent human papillomavirus (HPV) vaccine rates in the US highlight the need for catch-up vaccination. When teenagers enter college, there may be a shift in healthcare decision-making from parents and guardians to the students themselves. Little is known about factors influencing college students' healthcare decision-making processes. STUDY DESIGN: We evaluated HPV vaccine decision-making among 18-to-26-year-old college students through a self-administered, anonymous, cross-sectional survey. This survey was distributed to a sample of men and women in classroom settings at two universities. Categorical data comparisons were conducted using Chi-square and Fisher's exact tests. Multivariate Poisson regression was used to model initiation of HPV vaccine and compute prevalence ratios while controlling for key influential covariates at the 0.05 alpha level. RESULTS: A total of 527 students participated (response proportion=93.1%). Overall, 55.8% of participants received the HPV vaccine. Encouraging conversations with doctors and/or parents/guardians were identified as one of the most influential factors to increase vaccine uptake. Among students who received encouragement from both a doctor and parent, 95.8% received the vaccine. Campaigns about cancer prevention were viewed as more influential than those that focus on preventing genital warts. Approximately one-third of students indicated they didn't know where to get the HPV vaccine. Women were more likely to report that their parents would not let them get the HPV vaccine compared to men (26.7% vs. 2.3%). The majority of students (77.3%) indicated their parents were sometimes, equally, or mostly involved in making decisions about receiving vaccines (other than flu). CONCLUSION: Students' decision-making is greatly influenced by their parents; therefore, interventions for this population should work to increase students' control over decision-making while also addressing parental concerns.

Correlates of human papillomavirus (HPV) vaccination initiation and completion among 18-26 year olds in the United States.

PURPOSE: To examine correlates of HPV vaccination uptake in a nationally representative sample of 18-26-year-old adults. METHODS: Young adults aged 18-26 years were identified from the 2014 and 2015 National Health Interview Survey (n = 7588). Survey-weighted multivariable logistic regression models estimated sociodemographic factors associated with HPV vaccine initiation (≥1 dose) and completion (≥3 doses). RESULTS: Approximately 27% of study participants had initiated the HPV vaccine and 16% had completed the HPV vaccine. Participants were less likely to initiate the vaccine if they were men [(adjusted odds ratio) 0.19; (95% confidence interval) 0.16-0.23], had a high school diploma (0.40; 0.31-0.52) or less (0.46; 0.32-0.64) vs. college graduates, and were born outside the United States (0.52; 0.40-0.69). But, participants were more likely to initiate the HPV vaccine if they visited the doctor's office 1-5 times (2.09; 1.56-2.81), or ≥ 6 times (1.86; 1.48-2.34) within the last 12 months vs. no visits. Odds of completing HPV vaccine uptake followed the same pattern as initiation. And after stratifying the study population by gender and foreign-born status, these variables remained statistically significant. CONCLUSIONS: In our nationally representative study, only one out of six 18-26 year olds completed the required vaccine doses. Men, individuals with high school or less education, and those born outside the United States were less likely to initiate and complete the HPV vaccination. Our findings suggest that it may be useful to develop targeted interventions to promote HPV vaccination among those in the catch-up age range.

Human Papillomavirus Vaccination and Age at First Sexual Activity, National Health and Nutrition Examination Survey.

The National Health and Nutrition Examination Survey (NHANES) collects information on human papillomavirus (HPV) vaccination history as well as sexual activity. We evaluated data from NHANES to assess report of HPV vaccination with ≥1 dose and 3 doses among females and males aged 11 to 26 years during 2007-2014. We also examined age at first vaccine dose and age at first sexual activity among females aged 14 to 26 years. Vaccination significantly increased in females aged 13 to 26 years, but not among 11- to 12-year-old girls, and remained low for both females and males. In NHANES 2011-2014, among females with known age at first vaccine dose, 43.1% reported having had sex before or in the same year they received their first HPV vaccine, and this varied by race/ethnicity. Clinicians should provide strong recommendations consistent with guidelines, including routine vaccination of girls and boys at age 11 or 12 years.

Correlates of Human Papillomavirus Vaccine Completion Among Adolescent Girl Initiators.

OBJECTIVE: To examine correlates of vaccine series completion among young adolescent US girls who initiated the human papillomavirus (HPV) vaccine. METHODS: We analyzed National Immunization Survey-Teens 2012 provider-verified data to examine correlates of HPV vaccine completion among 13- to 17-year-old girls who initiated HPV vaccine in 2012 (N = 4548). RESULTS: The weighted vaccine series completion rate among 13- to 17-year-old girl initiators was 66.7% (95% confidence interval [CI], 64.0-69.3). Adolescent girls who were older, residents of the Northeast (adjusted prevalence ratio [aPR], 1.36; 95% CI, 1.07-1.73), and had provider-verified seasonal influenza vaccination in the past year (aPR, 1.67; 95% CI, 1.32-2.11) and provider recommendation (aPR, 1.40; 95% CI, 1.10-1.77) were more likely to complete the 3-dose vaccine series. CONCLUSIONS: Parents of younger adolescent girls need to be educated about the importance of completing the 3-dose HPV vaccine series. Provider recommendation for the vaccine would also facilitate series completion.

Age at HPV vaccine initiation and completion among US adolescent girls: trend from 2008 to 2012.

OBJECTIVE: To examine the trend of provider-verified HPV vaccine initiation (≥1 dose) and completion (≥3 doses) among adolescent girls at the Advisory Committee on Immunization Practices (ACIP) recommended age (11-12 years). METHODS: We analyzed National Immunization Survey of Teens 2008-2012 data and examined the trend of provider-verified HPV vaccine initiation and completion among <13 year old girls. RESULTS: Data on age at HPV vaccine initiation and completion were available for 24,466 and 15,972 girls, respectively. The weighted proportion of girls who initiated the vaccine at <13 years of age was 14.1%, 24.1%, 35.9%, 47.7% and 55.9% in 2008, 2009, 2010, 2011 and 2012, respectively (p for trend <.001). The similar trend was also observed for mean age at HPV vaccine initiation and completion (p<.001). CONCLUSIONS: Additional efforts are needed to increase HPV vaccine uptake among adolescent girls as only half of them receive this vaccine at ACIP recommended age.

Provider recommendation mediates the relationship between parental human papillomavirus (HPV) vaccine awareness and HPV vaccine initiation and completion among 13- to 17-year-old U.S. adolescent children.

OBJECTIVES: To examine the association between parental human papillomavirus (HPV) awareness and HPV vaccine initiation/completion based on 13- to 17-year-old US adolescent children and to explore whether these associations were mediated by provider recommendation. METHODS: We used publicly available National Immunization Survey-Teen 2011 data (11 236 adolescent girls and 12 328 boys). RESULTS: Weighted logistic regression analysis showed that parental HPV awareness and provider recommendation predicted HPV vaccine initiation and completion separately among both girls and boys, after adjusting for demographic and health care use variables. When provider recommendation and parental HPV awareness were entered in the model simultaneously, only provider recommendation was independently associated with HPV vaccine initiation and completion, demonstrating a mediation effect of provider recommendation. CONCLUSIONS: Future studies are needed to better understand why physicians may not provide a recommendation for the HPV vaccine as well as to identify strategies to improve providers' ability to effectively communicate their recommendations.

Correlates of human papillomavirus vaccine series completion among young adult female initiators.

Incomplete human papillomavirus (HPV) vaccination is a public health concern. The objective of this study was to examine the correlates of vaccine series completion among 18-26 year old US women using the Behavioral Risk Factor Surveillance System (BRFSS) data. Using BRFSS data collected during 2008-2010, we conducted multivariable logistic regression analysis to examine the correlates of HPV vaccine completion among HPV vaccine initiators. Among 656 women (18-26 years old) who initiated the HPV vaccine, the overall weighted vaccine series completion rate was 60.7%. It was 32.9%, 65.3%, and 69.9% in 2008, 2009, and 2010, respectively. Black and Hispanic women were less likely to complete the series compared with white women. Higher income, having a college degree and completion of the study in a more recent year were associated with higher completion rates. Thus, the reasons for HPV series non-completion may be multifactorial. Interventions targeting 18-26 year old female vaccine initiators with low income and education, and minority backgrounds may improve HPV vaccine series completion.