Human Vaccines & Immunotherapeutics

ISSN: 2164-5515 (Print) 2164-554X (Online) Journal homepage: http://www.tandfonline.com/loi/khvi20

Correlates of human papillomavirus vaccine series completion among young adult female initiators Mahbubur Rahman, Tabassum H Laz, Christine McGrath & Abbey B Berenson To cite this article: Mahbubur Rahman, Tabassum H Laz, Christine McGrath & Abbey B Berenson (2014) Correlates of human papillomavirus vaccine series completion among young adult female initiators, Human Vaccines & Immunotherapeutics, 10:8, 2163-2167, DOI: 10.4161/hv.29633 To link to this article: http://dx.doi.org/10.4161/hv.29633

Published online: 02 Jul 2014.

Submit your article to this journal

Article views: 64

View related articles

View Crossmark data

Citing articles: 1 View citing articles

Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=khvi20 Download by: [186.190.30.105]

Date: 05 November 2015, At: 15:09

Research Paper

Research Paper

Human Vaccines & Immunotherapeutics 10:8, 2163–2167; August 2014; © 2014 Landes Bioscience

Correlates of human papillomavirus vaccine series completion among young adult female initiators Mahbubur Rahman1,*, Tabassum H. Laz1, Christine J McGrath1, and Abbey B Berenson1 Department of Obstetrics and Gynecology and the Center for Interdisciplinary Research in Women’s Health; University of Texas Medical Branch; John Sealy Annex; Galveston, TX USA

1

Downloaded by [186.190.30.105] at 15:09 05 November 2015

Abbreviations: HPV, Human papillomavirus; BRFSS, Behavioral Risk Factor Surveillance System; ACIP, Advisory Committee on Immunization Practices; VFC, Vaccines for Children

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.

Introduction Human papillomavirus (HPV) infection is the most prevalent sexually transmitted infection in the US.1 Four HPV strains are responsible for 70% of cervical cancer (HPV 16 and 18) cases and 90% of genital warts (HPV 6 and 11) in women.2,3 The Advisory Committee on Immunization Practices (ACIP) recommends routine HPV vaccination for US girls 11–12 y of age and “catch-up” vaccination for those 13–26 y of age and not previously vaccinated.4,5 In spite of the proven efficacy of the HPV vaccine in protecting against precancerous lesions and genital warts in sexually active adolescents and young women,4,6,7 recent national data demonstrate low HPV vaccine uptake among 18–26 y old women in the US (23% for initiation and 13% for completion).8 Thus, 10% of young adult women did not complete the vaccine series, and therefore, may not have achieved the required immunity for protection.9 Correlates of HPV vaccine initiation and series completion have been widely investigated.8,10-16 In these studies and our earlier study,10 completion was measured as a proportion of the total number of women who answered questions on HPV vaccination. It is important to understand why women who initiate the vaccine do not complete the series, and whether there are racial and ethnic differences in vaccine completion.

Several studies have examined the correlates of HPV vaccine completion among young adult women initiators.8,17,18 However, two of these studies were based on data collected over 5 y ago, one examined correlates in 11–26 y old women17 and the other was based on members of a managed care organization.18 Only one study, based on nationally representative data collected in 2010, examined the correlates of HPV vaccine completion.8 No studies have examined annual trends of completion among initiators in the US. Moreover, there is a need to identify correlates for 18–26 y old women vaccine initiators as they (> 18 y olds) are ineligible for the Vaccine for Children (VFC) program and do not need parental consent for their vaccination. The objective of this study was to examine the correlates of vaccine series completion among 18–26 y old women who had initiated the vaccine using data collected through the Behavioral Risk Factor Surveillance System (BRFSS) study.

Results Based on data from 2008–2010, 97.5% (2632/2700) of 18–26 y old women responded to the questions on HPV vaccination. Among these, 656 initiated the HPV vaccine. The weighted HPV completion rate was 60.7% (95% CI 56.3–65.0%). Table 1

*Correspondence to: Mahbubur Rahman; Email: [email protected] Submitted: 04/01/2014; Revised: 06/06/2014; Accepted: 06/17/2014; Published Online: 07/02/2014 http://dx.doi.org/10.4161/hv.29633

www.landesbioscience.com Human Vaccines & Immunotherapeutics 2163

©2014 Landes Bioscience. Do not distribute.

Keywords: Human papillomavirus, HPV Vaccine, Vaccine initiation, Vaccine completion, Correlates, Young adult females, Behavioral Risk Factor Surveillance System

Total n = 656

Completed 3-dose series % (95% CI)

Age, year, n (%)

0.652

18–21

328

59.8 (53.5–65.7)

22–26

328

61.9 (55.2–68.1)

Race/ethnicity White

< 0.001 454

67.7 (62.5–72.5)

Black

63

37.6 (24.7–52.5)

Hispanic

95

47.7 (35.8–59.8)

Other

43

54.1 (35.0–72.0)

Marital Status, n (%)

Downloaded by [186.190.30.105] at 15:09 05 November 2015

P value

0.192

Single, never married

499

62.3 (57.2–67.1)

Married, divorced,

157

55.1 (45.4–64.4)

widowed, separated Education, n (%)

< 0.001

≤ HS

256

49.6 (42.3–56.9)

Some college hours

221

62.9 (55.2–70.0)

College graduate

171

74.5 (65.5–81.8)

Annual Household Income, US$, n (%)

0.015

< 50,000

226

52.4 (44.2–60.5)

50,000–75,000

143

59.4 (49.5–68.6)

> 75,000

88

73.3 (63.3–81.4)

Missing value

162

63.3 (54.4–71.5)

No

74

57.2 (42.9–70.3)

Yes

582

61.2 (56.5–65.7)

Have healthcare coverage, n (%)

0.192

Length of time since last routine medical check-up

0.122

≤1y

522

62.7 (57.6–67.4)

≥2y

134

53.2 (42.8–63.4)

Influenza vaccination in the past season

0.498

No

415

59.5 (53.6–65.1)

Yes

241

62.9 (55.3–69.8)

Overall

656

60.7 (56.3–65.0)

2008

169

32.9 (25.8–41.0)

2009

229

65.3 (57.3–72.6)

2010

258

69.9 (62.7–76.2)

HPV completion, weighted % (95% CI)

Region

0.012

Northeast

367

67.1 (52.3–67.6)

Midwest/West

151

67.3 (57.6–75.7)

South

138

47.0 (37.4–56.8)

a

a

< 0.001

Midwest and West were combined together to balance the sample size for each region.

2164 Human Vaccines & Immunotherapeutics

shows HPV vaccine completion status among initiators by sociodemographic characteristics. Ethnic differences were noted with higher completion rates among whites as compared with black and Hispanic women. Completion rates were also higher among initiators who had at least some college hours and those with an annual household income > $75,000. Women residing in the Northeast, Midwest, and the West had higher completion rates than women living in the South. Variables that met the screening criteria for inclusion in the multivariable logistic regression model were race/ ethnicity, education, marital status, income, healthcare coverage, history of routine medical check-up, year of study, and region of residence. Variables with P > 0.10 (marital status, healthcare coverage, and region of residence) were excluded from the final model. Among those who initiated the HPV vaccine, black and Hispanic women were less likely to complete the 3-dose series (Table 2). Women with a college degree, annual household income of > $75,000, and a routine medical check-up within the past year were more likely to complete the 3-dose series. Women vaccinated in 2009 and 2010 were more likely to complete the series compared with women who were vaccinated in 2008. In multivariable analyses by race/ ethnicity, almost similar results were observed in white women. However, among minority women, only year of vaccination was associated with vaccine series completion.

Discussion Our study showed that correlates of vaccine series completion among initiators and correlates of HPV vaccine completion among those who responded to HPV vaccination questions reported in the literature are different.8,10-16 Moreover, the evidence suggests racial differences in correlates of vaccine completion between white women and minority women. In this study, we observed that after HPV vaccine initiation, income, minority

Volume 10 Issue 8

©2014 Landes Bioscience. Do not distribute.

Table 1. HPV vaccine completion rate among initiators by different characteristics among 18–26 y old US women, 2008–2010

Table 2. Correlates of HPV vaccine series completion among 18–26 y old US women vaccine initiators, 2008–2010 Completed 3-dose series among initiators

Characteristics

Overall (n = 656) Adjusted odds ratio (95% CI)

White (n = 454) P value

Adjusted odds ratio (95% CI)

Black/ Hispanic/others (n = 202) P value

Adjusted odds ratio (95% CI)

P value

White

Reference

-

-

Black

0.35 (0.17–0.72)

0.004

-

-

Hispanic

0.45 (0.23–0.86)

0.015

-

-

Other

0.56 (0.24–1.29)

0.175

Reference

Reference

Downloaded by [186.190.30.105] at 15:09 05 November 2015

Education, ≤ HSa

Reference

Some college hours

1.52 (0.95–2.43)

0.078

1.56 (0.87–2.79)

0.133

1.51 (0.63–3.63)

0.357

College graduate

2.32 (1.29–4.17)

0.005

2.24 (1.06–4.74)

0.034

2.75 (0.94–8.04)

0.064

Annual Household Income, US$ < 50,000

Reference

Reference

Reference

50,000–75,000

0.94 (0.51–1.71)

0.832

1.13 (0.53–2.40)

0.745

0.59 (0.17–2.05)

0.399

> 75,000

1.92 (1.01–3.65)

0.045

2.40 (1.11–5.21)

0.027

1.23 (0.35–4.25)

0.745

Missing value

1.59 (0.92–2.64)

0.099

1.86 (0.91–3.82)

0.090

1.39 (0.55–3.53)

0.480

Length of time since last routine medical check-up ≥2y

Reference

≤1y

1.82 (1.06–3.14)

Reference 0.030

1.78 (0.94–3.37)

Reference 0.075

1.63 (0.49–5.36)

0.421

Study year

a

2008

Reference

2009

3.76 (2.22–6.37)

< 0.001

4.10 (2.15–7.84)

Reference < 0.001

2.97 (1.08–8.19)

Reference 0.036

2010

4.64 (2.75–7.84)

< 0.001

4.16 (2.25–7.67)

< 0.001

5.66 (1.99–16.10)

0.001

HS, High School; Adjusted by variables listed in this Table.

background and a college degree are important predictors of series completion. On the other hand our earlier study showed that age, marital status, college degree, income, healthcare coverage, routine medical check-up, influenza vaccination in the past 12 mo, and region were significant correlates of vaccine completion among women who responded to HPV vaccination questions. These results suggest that a subset of correlates need to be taken into account for interventions targeting series completion among young adult women vaccine initiators. Our findings show that among initiators, the rate of HPV vaccine series completion in 2010 (69.9%) is similar to that observed by Laz et al.’s study using 2010 National Health Interview Survey data.8 In addition to their findings that black women were less likely to complete the HPV vaccination series, we also observed that Hispanic women were less likely to be complete the series. Chou et al. observed similar racial disparities among women 11–26 y of age.17 We also observed that college graduation, high-income, and routine health check-up in the past year were associated with higher completion of the HPV vaccine series. The differences in correlates of vaccine completion between

our study and Laz et al.’s study could be due to sample size (656 vs. 408) and study year (2008–10 vs. 2010). Another study based on 18–26 y old female members of a managed care organization observed a separate set of correlates i.e., neighborhood education level, provider specialty, and healthcare utilization variables.18 These studies support the existence of racial disparities in regimen completion, along with other sociodemographic correlates. Our finding that minority women had lower rates of HPV vaccine completion is a major public health concern. It is well documented that black and Hispanic women have higher rates of cervical cancer compared with white women.19 Similarly, minority women have been shown to have disproportionately higher prevalence of both high and low-risk HPV types.1 Strategies to improve the HPV vaccine series completion among minority women are critically needed to lower the burden of HPV-related diseases and cancers. Moreover, as lower income is also associated with lower series completion, extension of the federal VFC program for 19–26 y old women may increase vaccine completion in this age group. We also observed higher HPV vaccine series completion among those who had undergone

www.landesbioscience.com Human Vaccines & Immunotherapeutics 2165

©2014 Landes Bioscience. Do not distribute.

Race/ethnicity

Materials and Methods The BRFSS, conducted by the Centers for Disease Control and Prevention (CDC) since 1984, is a cross-sectional telephone health survey among adults from all 50 US states, the District of Columbia, and US territories. More than 400,000 interviews are conducted in this survey each year, making it the largest ongoing health survey in the world. Details of the survey methods have been published elsewhere.20 Since the adult HPV module was introduced in 2008, we limited our study to 2008–2010 data in which 12 US states participated (Connecticut, Delaware, Kansas, Massachusetts, Minnesota, Nebraska, Oklahoma, Pennsylvania, Rhodes Island, Texas, West Virginia, and Wyoming). The response rates ranged from 43.4% to 66.9% in different years. We conducted a secondary analysis based on women who were included in our earlier study on geographic variations in HPV uptake in the US.10 For this study, however, we restricted our

sample to women aged 18–26 y who initiated HPV vaccine (≥ 1 dose). This study did not require approval from the University of Texas Medical Branch Institutional Review Board because the BRFSS is a publicly available de-identified database. This study focused on survey questions related to HPV vaccination status, number of doses received, socio-demographic characteristics, and health care utilization. The main outcome of interest was HPV completion (3 doses) among those who initiated the vaccine. HPV initiation was based on the question: “A vaccine to prevent the human papilloma virus or HPV infection is available and is called the cervical cancer or genital warts vaccine, HPV shot, (GARDASIL or CERVARIX). Have you ever had the HPV vaccination?” The response options were “yes” or “no.” Those who responded “yes” were considered HPV vaccine initiators and were further asked “How many HPV shots did you receive?” Those who had reported that they received three shots were considered HPV vaccine completers. The main exposures of interest in this study were sociodemographic characteristics and healthcare utilization variables. Age, race/ ethnicity, education, marital status, annual household income, last routine medical check-up, influenza vaccination in the past year, and health care coverage were categorized for the purpose of analysis. Region of residence was categorized as Northeast, Midwest, West, and South.21 We used STATA 12 svy commands (STATA Corporation, College Station, TX) for data analysis by incorporating probability sampling weights in conjunction with strata and primary sampling units (psu) generated by BRFSS complex survey design. Poststratification weight was used to correct for the complex BRFSS study design, and bias originated from nonresponse and non-telephone coverage. We used Chi-square tests for bivariate comparisons and multivariable logistic regression models to examine the correlates of HPV vaccine completion. Variables were screened for inclusion in an initial multivariable model. Candidate variables with a P value of ≤ 0.20 with the dependent variable were included in the initial multivariable model based on all women. After that, variables with P > 0.10 were excluded from the overall model. Similar independent variables were used in race/ethnicity based multivariable models. Adjusted odds ratio and 95% CIs for each of the correlates were reported. Disclosure of Potential Conflicts of Interest

No potential conflicts of interest were disclosed. Funding sources

Dr. McGrath is supported by a research career development award (K12HD052023: Building Interdisciplinary Research Careers in Women’s Health Program -BIRCWH) from the Office of Research on Women’s Health (ORWH), the Office of the Director (OD), the National Institute of Allergy and Infectious Diseases (NIAID), and NICHD at the National Institutes of Health.

2166 Human Vaccines & Immunotherapeutics

Volume 10 Issue 8

©2014 Landes Bioscience. Do not distribute.

Downloaded by [186.190.30.105] at 15:09 05 November 2015

a routine medical check-up in the past year, which may provide a window of opportunity for physicians to discuss the importance of completing the HPV vaccine series. We observed that completion of the 3-dose series has increased from 2008 to 2010, irrespective of race/ethnicity. Previous studies also support this notion. Chao et al.,18 Chou et al.,17 and Laz et al.8 based on 2006–07, 2007–08, and 2010 data observed completion rates of 47.1%, 31.2%, and 64.5%, respectively. While Chao et al. observed a higher completion rate than Chou et al., this discrepancy may be due to differences in study populations, as the former study was based on members of a managed care organization. The strength of this study is that it includes three years of data collected from 12 states; however, some limitations exist. Not all states within the US conducted the HPV vaccination uptake survey among young adult women in BRFSS study. We also do not know whether the women completed the 3-dose regimen within the CDC recommended timeframe. In addition, the multivariable analyses stratified by race/ethnicity were based on small number of observations and, therefore, we may not have enough power to make conclusive statements. Finally, the BRFSS survey is based on self-reported data which may be subject to recall bias. In spite of these limitations, this study provides important information regarding the correlates of HPV vaccine completion among a nationally representative sample of women who initiated the vaccine. Although the completion rate of HPV vaccine regimen increased during 2008–10, minority women who initiated the vaccine were less likely to complete the 3-dose series. Awareness of the necessity to complete the series regimen, extension of VFC program for 19–26 old women, and interventions targetting women with lower education levels and minority backgrounds may improve vaccine series completion among initiators.

1.

2.

3.

Downloaded by [186.190.30.105] at 15:09 05 November 2015

4.

5.

6.

Hariri S, Unger ER, Sternberg M, Dunne EF, Swan D, Patel S, Markowitz LE. Prevalence of genital human papillomavirus among females in the United States, the National Health And Nutrition Examination Survey, 2003-2006. J Infect Dis 2011; 204:566-73; PMID:21791659; http://dx.doi.org/10.1093/infdis/ jir341 Bosch FX, Burchell AN, Schiffman M, Giuliano AR, de Sanjose S, Bruni L, Tortolero-Luna G, Kjaer SK, Muñoz N. Epidemiology and natural history of human papillomavirus infections and type-specific implications in cervical neoplasia. Vaccine 2008; 26(Suppl 10):K1-16; PMID:18847553; http:// dx.doi.org/10.1016/j.vaccine.2008.05.064 Garland SM, Steben M, Sings HL, James M, Lu S, Railkar R, Barr E, Haupt RM, Joura EA. Natural history of genital warts: analysis of the placebo arm of 2 randomized phase III trials of a quadrivalent human papillomavirus (types 6, 11, 16, and 18) vaccine. J Infect Dis 2009; 199:805-14; PMID:19199546; http://dx.doi.org/10.1086/597071 Markowitz LE, Dunne EF, Saraiya M, Lawson HW, Chesson H, Unger ER; Centers for Disease Control and Prevention (CDC); Advisory Committee on Immunization Practices (ACIP). Quadrivalent human papillomavirus vaccine: Recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Recomm Rep 2007; 56(RR-2):124; PMID:17380109 Centers for Disease Control and Prevention (CDC). FDA licensure of bivalent human papillomavirus vaccine (HPV2, Cervarix) for use in females and updated HPV vaccination recommendations from the Advisory Committee on Immunization Practices (ACIP). MMWR Morb Mortal Wkly Rep 2010; 59:626-9; PMID:20508593 Garland SM, Hernandez-Avila M, Wheeler CM, Perez G, Harper DM, Leodolter S, Tang GW, Ferris DG, Steben M, Bryan J, et al.; Females United to Unilaterally Reduce Endo/Ectocervical Disease (FUTURE) I Investigators. Quadrivalent vaccine against human papillomavirus to prevent anogenital diseases. N Engl J Med 2007; 356:192843; PMID:17494926; http://dx.doi.org/10.1056/ NEJMoa061760

7.

8.

9.

10.

11.

12.

13.

Paavonen J, Naud P, Salmerón J, Wheeler CM, Chow SN, Apter D, Kitchener H, Castellsague X, Teixeira JC, Skinner SR, et al.; HPV PATRICIA Study Group. Efficacy of human papillomavirus (HPV)-16/18 AS04-adjuvanted vaccine against cervical infection and precancer caused by oncogenic HPV types (PATRICIA): final analysis of a doubleblind, randomised study in young women. Lancet 2009; 374:301-14; PMID:19586656; http://dx.doi. org/10.1016/S0140-6736(09)61248-4 Laz TH, Rahman M, Berenson AB. Human papillomavirus vaccine uptake among 18- to 26-yearold women in the United States: National Health Interview Survey, 2010. Cancer 2013; 119:138692; PMID:23508594; http://dx.doi.org/10.1002/ cncr.27894 Dobson SR, McNeil S, Dionne M, Dawar M, Ogilvie G, Krajden M, Sauvageau C, Scheifele DW, Kollmann TR, Halperin SA, et al. Immunogenicity of 2 doses of HPV vaccine in younger adolescents vs 3 doses in young women: a randomized clinical trial. JAMA 2013; 309:1793-802; PMID:23632723; http://dx.doi.org/10.1001/jama.2013.1625 Rahman M. LAZ TH, Berenson AB. Geographic variation in human papillomavirus vaccination uptake among young adult women in the United States during 2008-2010. Vaccine.  2013 Nov 12;31(47):5495-9 Jain N, Euler GL, Shefer A, Lu P, Yankey D, Markowitz L. Human papillomavirus (HPV) awareness and vaccination initiation among women in the United States, National Immunization Survey-Adult 2007. Prev Med 2009; 48:426-31; PMID:19100762; http://dx.doi.org/10.1016/j. ypmed.2008.11.010 Caskey R, Lindau ST, Alexander GC. Knowledge and early adoption of the HPV vaccine among girls and young women: results of a national survey. J Adolesc Health 2009; 45:453-62; PMID:19837351; http:// dx.doi.org/10.1016/j.jadohealth.2009.04.021 Taylor LD, Hariri S, Sternberg M, Dunne EF, Markowitz LE. Human papillomavirus vaccine coverage in the United States, National Health and Nutrition Examination Survey, 2007-2008. Prev Med 2011; 52:398-400; PMID:21108962; http://dx.doi. org/10.1016/j.ypmed.2010.11.006

14. Anhang Price R, Tiro JA, Saraiya M, Meissner H, Breen N. Use of human papillomavirus vaccines among young adult women in the United States: an analysis of the 2008 National Health Interview Survey. Cancer 2011; 117:5560-8; PMID:21732336; http://dx.doi.org/10.1002/cncr.26244 15. Centers for Disease Control and Prevention. Vaccination coverage estimates from the National Health Interview Survey: United States, 2008. NCHS Health E-Stats 2009. Available from URL: http:// www.cdc.gov/nchs/data/hestat/vaccine_coverage/ vaccine_coverage.pdf [Accessed Jan 11, 2014] 16. Williams WW, Lu PJ, Saraiya M, Yankey D, Dorell C, Rodriguez JL, Kepka D, Markowitz LE. Factors associated with human papillomavirus vaccination among young adult women in the United States. Vaccine 2013; 31:2937-46; PMID:23643629; http:// dx.doi.org/10.1016/j.vaccine.2013.04.041 17. Chou B, Krill LS, Horton BB, Barat CE, Trimble CL. Disparities in human papillomavirus vaccine completion among vaccine initiators. Obstet Gynecol 2011; 118:14-20; PMID:21691158; http://dx.doi. org/10.1097/AOG.0b013e318220ebf3 18. Chao C, Velicer C, Slezak JM, Jacobsen SJ. Correlates for completion of 3-dose regimen of HPV vaccine in female members of a managed care organization. Mayo Clin Proc 2009; 84:864-70; PMID:19797775; http://dx.doi.org/10.4065/84.10.864 19. Watson M, Saraiya M, Benard V, Coughlin SS, Flowers L, Cokkinides V, Schwenn M, Huang Y, Giuliano A. Burden of cervical cancer in the United States, 1998-2003. Cancer 2008; 113(Suppl):285564; PMID:18980204; http://dx.doi.org/10.1002/ cncr.23756 20. Mokdad AH. The Behavioral Risk Factors Surveillance System: past, present, and future. Annu Rev Public Health 2009; 30:43-54; PMID:19705555; http://dx.doi.org/10.1146/ annurev.publhealth.031308.100226 21. Census Bureau Regions and Divisions with State FIPS Codes”. US Census Bureau. http://www.census. gov/geo/www/us_regdiv.pdf. Accessed on Feb 24, 2013.

www.landesbioscience.com Human Vaccines & Immunotherapeutics 2167

©2014 Landes Bioscience. Do not distribute.

References

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 ser...
888KB Sizes 1 Downloads 6 Views