Abstract
Background:
Human papillomavirus (HPV) vaccination is the most effective biomedical intervention for HPV infections. HPV vaccination rate among sexually active young adults is largely unknown.
Methods:
Patients aged 18–26 years, who attended the Rhode Island Sexually Transmitted Infections Clinic between 2013–2018, were included in the study. We extracted demographics, behavioral characteristics, and HPV vaccination status from electronic medical records. Exploratory logistic regressions were conducted to identify factors associated with vaccination status.
Results:
Among 2729 eligible individuals, the median age was 23 years (interquartile range: 22–25). Only 8.1% of males and 24.8% of females received at least one dose of HPV vaccine. Females were 144% (crude odds ratio [cOR]: 2.44, 95% confidence interval [CI]: 2.03, 2.94) more likely to receive at least one dose of HPV vaccine than males. Being Black/African American (B/AA) or Hispanic/Latino (H/L) was associated with a 21% (cOR: 0.79, 95% CI: 0.62, 1.00) and 34% (cOR: 0.66, 95% CI: 0.53, 0.81) decrease in the odds of vaccination, respectively.
Conclusions:
HPV vaccination rate was low among sexually active young adults. Gender and racial/ethnic disparities existed in HPV vaccination. Interventions are needed to promote HPV vaccination among sexually active young adults, especially B/AA and H/L communities.
Keywords: HPV (human papillomavirus), viral disease, vaccination
Short summary
A study of patients in an STI clinic in Rhode Island found that HPV vaccination rate was low among sexually active young adults. Racial/ethnic and sexual disparities exist in HPV vaccination.
Introduction
Human papillomavirus (HPV) is the most common sexually transmitted infection (STI) in the United States (US).1 Currently, 79 million people in the US are infected with HPV, with approximately 14 million new cases arising each year.2 Among sexually active people, 75%–85% have at least one HPV infection during their lifetime.3 While most HPV infections are asymptomatic and resolve without treatment, persistent HPV infections are cause for an estimated 355,000 new cases of genital warts and 45,300 cases of cancer within the US each year.4–6 HPV accounts for more than 90% of cervical cancers, 70% of oropharyngeal cancer, and 60–75% of anogenital cancers such as cancer of the vulva, vagina, penis, and anus.7 HPV infections impose a substantial disease burden, and accrue an annual medical cost of $8 billion in preventative and treatment related procedures in the US.4 As a consequence, there is a dire need for new preventative efforts to protect people from HPV-related diseases.
Vaccination is one of the most cost-effective methods for HPV prevention. Among the estimated 34,800 HPV-related cancer cases reported annually, 92% are attributable to genotypes targeted by the HPV vaccine and may have been prevented had vaccine recommendations been followed.8 By receiving the recommended doses, an individual can achieve nearly complete immunity against infection by genotypes known to cause the majority of HPV-related diseases.9–11 Not only have large-scale population studies shown that vaccination significantly decreases the prevalence of HPV,12 genital warts,13 and cervical precancers14, but studies have also found that the vaccine can prevent 70–90% of HPV-related genital wart and cancer cases.15 As a byproduct, HPV vaccination is indicated as one of the most cost-effective methods to protect against genital warts and HPV-related cancers.
Currently, recommendations for HPV prevention include routine vaccination for adolescents, and if inadequately vaccinated, catch up for young adults through age 26. Although young adults have the highest HPV infection rate across age groups,16 they may still benefit from vaccination as the majority of young adults have yet to be exposed to all high-risk genotypes covered by the 9-valent HPV vaccine.17,18 Despite the high efficacy and recommendation by the Advisory Committee on Immunization Practices (ACIP), HPV vaccination rates remain low and as few as 40% of young adults ages 18–26 received one or more doses of the HPV vaccine in 2018.19 Although sexually active young adults are at high risk for HPV infection, studies have yet to explore factors associated with HPV vaccination in this population.20,21 In this study, we aim to address this gap by exploring factors associated with HPV vaccination in sexually active young adults.
Methods
In our study, we conducted a secondary data analysis using data collected through routine clinical care at a publicly funded STI clinic in Rhode Island between 2013 to 2018. We reviewed basic demographic (e.g. race, ethnicity, and gender) and socioeconomic characteristics (e.g. insurance status, education level, and income), self-reported sexual and HIV risk behaviors (e.g. total number of partners, intoxication during sex) in the past 6 months during their visits, and STI diagnoses (e.g. gonorrhea, chlamydia, and syphilis) by laboratory testing. We tested urine, genital, and rectum samples for gonorrhea and chlamydia. In the case that a patient had multiple STI clinic visits, only the first visit’s respective STI intake form was reviewed for the study. To determine HPV vaccination status, the patient’s response to a single question was used, “Have you been vaccinated for HPV?”. If individuals did not respond to this question or responded “do not remember” for this question, they were excluded from the study.
Bivariate analyses were conducted to present the demographic and behavioral characteristics by HPV vaccination status. Additionally, Chi-square and Kruskal-Wallis tests were used to test the distributions of demographics and behavioral characteristics by HPV vaccination status. Logistic regressions were then conducted to explore factors associated with HPV vaccination. Confounding variables were identified by a priori substantial knowledge and causal graphs. All analyses were performed in Stata 15.0 (Stata-Corp LLC, College Station, Texas). This study was approved by The Miriam Hospital Institutional Review Board.
Results
Of 2729 sexually active young adults, the median age was 23 years old (IQR: 22–25). The majority reported being male (63.5%), white (46.8%), non-Hispanic (69.7%), heterosexual (73%), and uninsured (51.3%) (Table 1). Black/African Americans (B/AA) and Hispanic/Latinos (H/L) accounted for 22.6% and 30.3% of the study population, respectively. Among the study population, 20% were individuals who reported only having same-sex partners and 7.3% were bisexual. Most participants had a low perceived HIV risk and over half were screened for HIV in the past 12 months. The median number of sex partners in the past 12 months was 3 (IQR: 2–5). The prevalence of gonorrhea, chlamydia, and syphilis was 5.2%, 18.0%, and 2.0%, respectively.
Table 1.
HPV vaccination among young adults presenting to a STDs clinic.
| HPV vaccination |
|||||
|---|---|---|---|---|---|
| No |
Yes |
||||
| Variables | N = 2141 | % | N = 588 | % | p value |
|
| |||||
| Age (median, IQR)† | 23 (22, 25) | 23 (21, 25) | 0.003 | ||
| Gender | <0.001 | ||||
| Male | 1401 | 65.4 | 257 | 43.7 | |
| Female | 740 | 34.6 | 331 | 56.3 | |
| Race | <0.001 | ||||
| White | 961 | 45.4 | 316 | 54.1 | |
| AA/Black | 486 | 23.0 | 126 | 21.6 | |
| Other | 668 | 31.6 | 142 | 24.3 | |
| Ethnicity | <0.001 | ||||
| Hispanic/Latino | 672 | 31.6 | 137 | 23.4 | |
| Non-Hispanic | 1452 | 68.4 | 449 | 76.6 | |
| Insurance status | 0.001 | ||||
| Uninsured | 1115 | 52.5 | 261 | 44.8 | |
| Insured | 1008 | 47.5 | 321 | 55.2 | |
| Sexual orientation (all) | 0.12 | ||||
| Heterosexual | 1543 | 73.3 | 409 | 70.2 | |
| Homosexual | 420 | 20.0 | 121 | 20.8 | |
| Bisexual | 142 | 6.7 | 53 | 9.1 | |
| Sexual orientation (male) | <0.001 | ||||
| Heterosexual | 888 | 14.8 | 112 | 12 | |
| Homosexual | 405 | 6.7 | 115 | 12.3 | |
| Bisexual | 87 | 1.4 | 26 | 2.8 | |
| Sexual orientation (female) | 0.93 | ||||
| Heterosexual | 655 | 10.9 | 297 | 31.7 | |
| Homosexual | 15 | 0.2 | 6 | 0.6 | |
| Bisexual | 55 | 0.9 | 27 | 2.9 | |
| Year of clinic visit | 0.41 | ||||
| 2013 | 121 | 5.7 | 31 | 5.3 | |
| 2014 | 260 | 12.1 | 61 | 10.4 | |
| 2015 | 334 | 15.6 | 103 | 17.5 | |
| 2016 | 437 | 20.4 | 129 | 21.9 | |
| 2017 | 472 | 22.0 | 139 | 23.6 | |
| 2018 | 517 | 24.1 | 125 | 21.3 | |
| Self-perceived HIV risk | 0.006 | ||||
| None/low | 1649 | 88.8 | 433 | 84.2 | |
| Medium/high | 209 | 11.2 | 81 | 15.8 | |
| Previous HIV test ever | 0.008 | ||||
| No | 994 | 46.6 | 238 | 40.5 | |
| Yes | 1139 | 53.4 | 350 | 59.5 | |
| Number of total partners reported (median, IQR)a | 3 (2,5) | 3 (2, 6) | 0.04 | ||
| Anonymous partner | 0.9 | ||||
| No | 1335 | 62.6 | 370 | 62.9 | |
| Yes | 796 | 37.4 | 218 | 37.1 | |
| Intoxicated or high before having sex | 0.002 | ||||
| No | 1345 | 63.0 | 329 | 56.0 | |
| Yes | 789 | 37.0 | 258 | 44.0 | |
| STD tested positive in the last 12 months | 0.001 | ||||
| No | 1843 | 86.4 | 476 | 81.1 | |
| Yes | 291 | 13.6 | 111 | 18.9 | |
| Ever heard of PrEP | <0.001 | ||||
| No | 1656 | 78.0 | 386 | 65.8 | |
| Yes | 467 | 22.0 | 201 | 34.2 | |
| Clinical outcomesb | |||||
| Gonorrhea (any sitec) | 0.57 | ||||
| Negative | 1937 | 94.6 | 539 | 95.2 | |
| Positive | 110 | 5.4 | 27 | 4.8 | |
| Chlamydia (any sitec) | 0.29 | ||||
| Negative | 1663 | 81.6 | 472 | 83.5 | |
| Positive | 375 | 18.4 | 93 | 16.5 | |
| Syphilis | 0.02 | ||||
| Negative | 1877 | 98.4 | 502 | 96.7 | |
| Positive | 31 | 1.6 | 17 | 3.3 | |
= Continuous variable reported as mean and median (IQR). Significance tested using Kruskal–Wallis test.
= Percent calculated from patients tested
= any sites include urine, genital, and rectum.
Of the young adults aged 18–26 years, 21.5% received at least one dose of an HPV vaccine. Only 8.1% of men and 24.3% of women reported ever receiving at least one dose of HPV vaccination. Among breakdown by sexual orientation, those who identified as bisexual had the highest vaccination rate (27.2%), followed by men who have sex with men only (MSMO) (22.4%) and heterosexual individuals (21.0%). Being female, white, non-Hispanic, and insured were all associated with a higher chance of being vaccinated (all p values <0.05). In opposition to their unvaccinated counterparts, individuals who were vaccinated were more likely to have a greater number of sexual partners in the past 12 months, been previously tested for HIV, and have a positive STI test result in the past 12 months. Prevalence of clinically diagnosed gonorrhea and chlamydia were not statistically significant between vaccination groups, however, findings indicated vaccinated young adults were more likely to have a syphilis infection than those who were unvaccinated (3.3% vs. 1.6%, p < .001).
Table 2 presents results from the multivariable logistic regression analyses. We found that a one-unit increase in age was associated with a 6% (crude odds ratio [cOR]: 0.94, 95% confidence interval [CI]: 0.90–0.98) decrease in the odds of being vaccinated. B/AA were 21% (cOR: 0.79, 95% CI: 0.62, 1.00) less likely to be vaccinated for HPV than white counterparts and identification as H/L was associated with a 34% (cOR: 0.66, 95% CI: 0.53, 0.81) decrease in the odds of being vaccinated, when compared to non-Hispanic young adults. Additionally, findings indicated that insurance status and sexual orientation among males was associated with vaccination status. Individuals who were insured were 34% (adjusted odds ratio [aOR]: 1.34, 95% CI: 1.11, 1.61) more likely to be vaccinated and males who identified as bisexual were 130% (adjusted odds ratio [aOR]:2.18, 95% CI: 1.41–3.74) more likely to be vaccinated than those who identified as heterosexual. Lastly, MSMO had a 2.18-fold odds (aOR: 2.18, 95% CI: 1.62–2.92) of being vaccinated when compared to individuals who identified as heterosexual. No significant associations were observed between sexual orientation and HPV vaccination among females.
Table 2.
Demographic and behavioral factors associated with any dose of HPV vaccination.
| Risk factors | Odds ratio (95% confidence interval) |
|---|---|
|
| |
| Agea | 0.94 (0.90,0.98) |
| Racea | |
| White | 1 |
| Black/African American | 0.79 (0.62, 1.00) |
| Other | 0.65 (0.52, 0.81) |
| Ethnicitya | |
| Non-Hispanic | 1 |
| Hispanic | 0.66 (0.53, 0.81) |
| Insuranceb | |
| Uninsured | 1 |
| Insured | 1.34 (1.11, 1.61) |
| Sexual orientation (total)b | |
| Heterosexual | 1 |
| Same-sex | 1.02 (0.81, 1.29) |
| Bisexual | 1.34 (0.96, 1.88) |
| Sexual orientation (male)b | |
| Heterosexual | 1 |
| Same-sex | 2.18 (1.62, 2.92) |
| Bisexual | 2.30 (1.41, 3.74) |
| Sexual orientation (female)b | |
| Heterosexual | 1 |
| Same-sex | 0.94 (0.35, 2.47) |
| Bisexual | 1.05 (0.65, 1.71) |
crude odds ratios were reported
adjusted for age, race, and ethnicity
Discussion
This is one of few studies that provides a detailed exploration of factors associated with HPV vaccination rates among sexually active young adults ages 18–26 years. Findings from our study indicate that sexually active young adults were even less likely to have received at least one dose of an HPV vaccination (21.5%) than that reported by the national survey in 2018 (39.9%).19 Though HPV vaccination is prophylactic and optimal protection can be achieved before an individual becomes sexually active, those who have not yet been vaccinated and are sexually active should still seek HPV vaccination. This recommendation is backed by numerous studies that have shown that the majority of sexually active young adults had not yet been exposed to oncogenic HPV strains covered by the HPV vaccine.17,18 That said, false notion that the HPV vaccination is solely for individuals who are not sexually active may attribute to the low HPV vaccination rates seen among sexually active young adults. To correct misunderstandings, education is needed to improve general knowledge of eligibility for the HPV vaccine and promote vaccination among sexually active young adults.
The observed differences based on sexual orientation have been reported by others.20,21 This pattern was strongly reinforced by our data which indicated that both bisexual men and MSMO were twice as likely to receive HPV vaccination than heterosexual men (Table 2). However, this finding was only significant among male sexual minorities. Associations between sexual orientation and vaccination status were not significant for females within our study population – this finding was similar to that reported by Charlton et al.’s longitudinal cohort study among males and females within the US.21 This phenomenon may be attributed to the Advisory Committee on Immunization Practices (ACIP) Adult Immunization Recommendations that were released in 2016. These guidelines listed bisexual men and MSMO as high-risk groups for HPV-related diseases and accordingly, made explicit recommendations that they obtain HPV vaccination.22 Providers’ recommendation for HPV vaccination likely adapted in response to these guidelines, thus contributing to the increase in vaccination rates among bisexual and MSMO sexual minorities.23 Additionally, HPV vaccine recommendations have consistently targeted females regardless of sexual orientation. As a result, we are not surprised by the non-significant association between sexual orientation and HPV vaccination among females. Overall, study findings indicate that community-tailored efforts and targeted-interventions are needed to address a gap within HPV prevention for heterosexual men.
In addition to significant associations among sexual orientation, our findings indicate the existence of racial/ethnic disparities within HPV vaccination. Young adults who identified as B/AA or H/L had notably lower vaccination rates compared to individuals who identified as white or non-Hispanic. These indicators for racial/ethnic disparities within HPV vaccination are supported by multiple studies and may be attributable to several factors including limited resources to prevention services,24 low awareness of HPV and HPV vaccination,25,26 cultural barriers,27 and medical mistrust.27 Given the high HPV infection rates and low HPV vaccination rates among B/AA and H/L identifying individuals,28 culturally-tailored interventions are needed to promote HPV vaccination among B/AA and H/L communities.
Insurance status was also found to play a major role in HPV vaccination rates among our study population. Our findings indicated that insured young adults were 34% more likely to receive at least one dose of an HPV vaccine compared to individuals who were uninsured. Today, most insurers cover the cost of HPV vaccination if initiated before an individual is 26 years old.29 However, without insurance coverage, the cost of the HPV vaccine is approximately $250 per dose.30 As a result, individuals who initiate HPV vaccination after the age of 15 are required to receive three doses and, if uninsured, may need to pay up to $750 for the complete, three-dose vaccination. Consequently, this may impose a major barrier to vaccination uptake and indicates a need for cost assistant programs and expansion of health coverage.
Lastly, our study was subject to a few limitations. Data used for analysis was self-reported, thus recall and reporting bias may influence findings. Additionally, a single question was used to assess HPV vaccination status. Due to the HPV vaccination’s 3-dose regimen, we were unable to determine if individuals had successfully completed the entire series of doses needed for optimal protection. Though these obstacles necessitate further research, our study was also strengthened by multiple factors. Most noteworthy was access to a sizeable dataset. Since our study utilized information provided by a publicly-funded clinic with statewide reach and a robust STI screening program, we were able to counter-balance limitations with a large sample size and power for detection of true differences.
Conclusions
Among young adults ages 18–26 years, the rate of receiving at least one dose of the HPV vaccination was lower for those who were sexually active. In our study, findings indicate that sexual orientation and racial/ethnic disparities exist within HPV vaccination. To reduce HPV-related disease burden, novel interventions are needed to promote HPV vaccination among sexually active young adults. Further, results indicate that culturally conscientious, community-tailored interventions addressing disparities among sexual minorities have great potential for improving current vaccine promotion strategies. From our study’s findings, insurance status was also found to serve as a reliable predictor of vaccination status. Accordingly, cost assist programs and expansion of insurance coverage pose great implications on reducing barriers associated with the financial accessibility of the HPV vaccine. Conclusively, our study provides a better understanding of HPV vaccination rates and related risk factors among young adults. These findings serve as an invaluable tool for the development of HPV vaccination promotion interventions that are tailored to the specific needs of sexually active young adults.
Funding
The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: Dr. Tao is supported by grants from the National Institutes of Health (K01MH19660) and the Providence/Boston Center for AIDS Research (P30AI042853).
Footnotes
Declaration of conflicting interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
References
- 1.Satterwhite CL, Torrone E, Meites E, et al. Sexually transmitted infections among US women and men: prevalence and incidence estimates. Sex Transmitted Diseases 2013; 40(3): 187–193. DOI: 10.1097/OLQ.0b013e318286bb53 [DOI] [PubMed] [Google Scholar]
- 2.Purcell DW, Johnson CH, Lansky A, et al. Estimating the population size of men who have sex with men in the United States to obtain HIV and syphilis rates. Open AIDS Journal 2012; 6: 98–107. DOI: 10.2174/1874613601206010098 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 3.Weaver BA. Epidemiology and natural history of genital human papillomavirus infection. J Am Osteopathic Assoc 2006; 106(3 Suppl 1): S2–S8. [PubMed] [Google Scholar]
- 4.Chesson HW, Ekwueme DU, Saraiya M, et al. Estimates of the annual direct medical costs of the prevention and treatment of disease associated with human papillomavirus in the United States. Vaccine 2012; 30(42): 6016–6019. DOI: 10.1016/j.vaccine.2012.07.056. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.Jemal A, Simard EP, Dorell C, et al. Annual report to the nation on the status of cancer, 1975–2009, featuring the burden and trends in human papillomavirus(HPV)-associated cancers and HPV vaccination coverage levels. J Natl Cancer Inst 2013; 105(3): 175–201. DOI: 10.1093/jnci/djs491 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 6.Patel H, Wagner M, Singhal P, et al. Systematic review of the incidence and prevalence of genital warts. BMC Infectious Diseases 2013; 13: 39. DOI: 10.1186/1471-2334-13-39. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 7.Giuliano AR, Tortolero-Luna G, Ferrer E, et al. Epidemiology of human papillomavirus infection in men, cancers other than cervical and benign conditions. Vaccine 2008; 26(Suppl 100 10): K17–K28. DOI: 10.1016/j.vaccine.2008.06.021. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 8.Senkomago V, Henley SJ, Thomas CC, et al. Human papillomavirus–attributable cancers—United States, 2012–2016. Morbidity Mortality Weekly Rep 2019; 68(33): 724–728. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 9.Harper DM, Franco EL, Wheeler C, et al. Efficacy of a bivalent L1 virus-like particle vaccine in prevention of infection with human papillomavirus types 16 and 18 in young women: a randomised controlled trial. Lancet (London, England) 2004; 364(9447): 1757–1765. DOI: 10.1016/s0140-6736(04)17398-4. [DOI] [PubMed] [Google Scholar]
- 10.Harper DM, Franco EL, Wheeler CM, et al. Sustained efficacy up to 4.5 years of a bivalent L1 virus-like particle vaccine against human papillomavirus types 16 and 18: follow-up from a randomised control trial. Lancet (London, England) 2006; 367(9518): 1247–1255. DOI: 10.1016/s0140-6736(06)68439-0. [DOI] [PubMed] [Google Scholar]
- 11.Villa LL, Ault KA, Giuliano AR, et al. Immunologic responses following administration of a vaccine targeting human papillomavirus types 6, 11, 16, and 18. Vaccine 2006; 24(27–28): 5571–5583. DOI: 10.1016/j.vaccine.2006.04.068. [DOI] [PubMed] [Google Scholar]
- 12.Markowitz LE, Hariri S, Lin C, et al. Reduction in human papillomavirus (HPV) prevalence among young women following HPV vaccine introduction in the United States, national health and nutrition examination surveys, 2003–2010. J Infectious Diseases 2013; 208(3): 385–393. DOI: 10.1093/infdis/jit192. [DOI] [PubMed] [Google Scholar]
- 13.Lukács A, Máté Z, Farkas N, et al. The quadrivalent HPV vaccine is protective against genital warts: a meta-analysis. BMC Public Health 2020; 20(1): 691. DOI: 10.1186/s12889-020-08753-y. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14.McClung NM, Gargano JW, Bennett NM, et al. Trends in human papillomavirus vaccine types 16 and 18 in cervical precancers, 2008–2014. Cancer Epidemiology, Biomarkers Prevention: A Publication Am Assoc Cancer Res Cosponsored by Am Soc Prev Oncol 2019; 28(3): 602–609. DOI: 10.1158/1055-9965.Epi-18-0885. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 15.Serrano B, Brotons M, Bosch FX, et al. Epidemiology and burden of HPV-related disease. Best Practice Research Clin Obstetrics Gynaecology 2018; 47: 14–26. DOI: 10.1016/j.bpobgyn.2017.08.006. [DOI] [PubMed] [Google Scholar]
- 16.Dunne EF, Unger ER, Sternberg M, et al. Prevalence of HPV infection among females in the United States. Jama 2007; 297(8): 813–819. DOI: 10.1001/jama.297.8.813. [DOI] [PubMed] [Google Scholar]
- 17.King EM, Mesher D, Sonnenberg P, et al. HPV16 and HPV18 seropositivity and DNA detection among men who have sex with men: a cross-sectional study conducted in a sexual health clinic in London. Sex Transmitted Diseases 2020; 97: 1–5. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 18.King EM, Gilson R, Beddows S, et al. Human papillomavirus DNA in men who have sex with men: type-specific prevalence, risk factors and implications for vaccination strategies. Br J Cancer 2015; 112(9): 1585–1593. DOI: 10.1038/bjc.2015.90. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 19.Molina JM, Capitant C, Spire B, et al. On-demand pre-exposure prophylaxis in men at high risk for HIV-1 infection. New Engl Journal Medicine 2015; 373(23): 2237–2246. DOI: 10.1056/NEJMoa1506273. [DOI] [PubMed] [Google Scholar]
- 20.Agénor MA-O, Peitzmeier SM, Gordon AR, et al. Sexual orientation identity disparities in human papillomavirus vaccination initiation and completion among young adult US women and men. Cancer Causes Control 2016; 27(10): 1187–1196. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 21.Charlton BM, Reisner SL, Agénor M, et al. Sexual orientation disparities in human papillomavirus vaccination in a longitudinal cohort of U.S. males and females. LGBT Health 2017; 4(3): 202–209. DOI: 10.1089/lgbt.2016.0103. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 22.Savoy M ACIP releases 2016 adult immunization recommendations. Am Family Physician 2016; 93(4): 323–326. [PubMed] [Google Scholar]
- 23.Gerend MA, Madkins K, Phillips G 2nd, et al. Predictors of human papillomavirus vaccination among young men who have sex with men. Sex Transmitted Diseases 2016; 43(3): 185–191. DOI: 10.1097/olq.0000000000000408. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 24.Meites E, Llata E, Hariri S, et al. HPV vaccine implementation in STD clinics–STD surveillance network. Sex Transmitted Diseases 2012; 39(1): 32–34. DOI: 10.1097/OLQ.0b013e3182315584. [DOI] [PubMed] [Google Scholar]
- 25.Wilson R, Brown DR, Boothe MA, et al. Knowledge and acceptability of the HPV vaccine among ethnically diverse black women. J Immigr Minor Health 2013; 15(4): 747–757. [DOI] [PubMed] [Google Scholar]
- 26.National state. local area vaccination coverage among adolescents aged 13–17 years — United States, 2009. MMWR Morbidity Mortality Weekly Report 2010; 59(32): 1018–1023. [PubMed] [Google Scholar]
- 27.Luque JS, Raychowdhury SF and Weaver M. Health care provider challenges for reaching hispanic immigrants with HPV vaccination in rural Georgia. Rural Remote Health 2012; 12(2): 1975. [PubMed] [Google Scholar]
- 28.McQuillan GM, Kruszon-Moran D, Markowitz LE, et al. Prevalence of HPV in adults aged 18–69: United States, 2011–2014. NCHS Data Brief 2017; 280: 1–8. [PubMed] [Google Scholar]
- 29.Patel RR, Harrison LC, Patel VV, et al. HIV pre-exposure prophylaxis programs incorporating social applications can reach at-risk men who have sex with men for successful linkage to care in Missouri, USA. J Assoc Nurses AIDS Care 2017; 28: 428–430. DOI: 10.1016/j.jana.2017.01.003. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 30.Chan PA and Flanigan TP. Effective HIV prevention interventions and the need for rapid mobilization to address hiv outbreaks among at-risk populations. J Infectious Diseases 2017; 215: 1491–1492. DOI: 10.1093/infdis/jix101. [DOI] [PMC free article] [PubMed] [Google Scholar]