Abstract
This national cohort study examines National Immunization Survey–Teen to assess the association of adolescents’ ability to consent to human papillomavirus vaccination without parental involvement with vaccination rates.
Despite the safety and efficacy of human papillomavirus (HPV) vaccine, immunization rates remain lower than other adolescent vaccines, with only 54% of adolescents in the US up to date with the multidose series.1 Legislation that permits adolescents to consent to HPV vaccination without parental involvement is a policy option for improving immunization rates.2 While 8 states and Washington, DC, currently have policies that permit adolescents to consent to HPV vaccination, the effect of these policies on immunization rates remains unknown, to our knowledge. In this study, we investigate the association between adolescents’ ability to consent to HPV vaccination and rates of vaccine initiation and completion.
Methods
In this cross-sectional study, we analyzed National Immunization Survey–Teen (NIS-Teen), a national data set that compiles vaccination data for adolescents in the US. For 2015 through 2018, we included adolescent data with adequate clinician-reported vaccination records while applying recommended clinician sampling weights and survey procedures, which accounted for clustering by states. Because it used deidentified, publicly available data, the study did not meet the definition of human subjects research of the Yale School of Medicine’s institutional review board, and therefore ethical review and informed consent were not required.
Adolescents were classified as either permitted or not permitted to consent to HPV vaccination according to their state of residence, age, and year of survey, based on the year of enactment of state bills and laws as described by Silverman et al.2 For 1 or more survey years, the following states permitted adolescents to consent to HPV vaccination: Alabama, Alaska, California, Delaware, Idaho, New York, Oregon, and South Carolina, plus Washington, DC. Logistic regression was used to examine the association between permitting adolescents to consent to HPV vaccination and vaccine uptake. Two-sided P values less than .05 were considered significant. Multivariable models were used to adjust for potential confounders. To build the full model, individual covariate assessments, collinearity diagnostics, and a stepwise forward inclusion procedure with comparisons based on the Akaike information criteria were performed. Sensitivity analysis excluded adolescents residing in states with school mandates for HPV vaccine. Analysis was completed in SAS version 9.4 (SAS Institute)3 from July 2020 to September 2021.
Results
The data set included 81 899 adolescents aged 13 to 17 years, with 38 942 girls (49.0%) and a mean (SD) age of 15.0 (1.4) years. Sociodemographic characteristics of the overall cohort and by permission to consent to HPV vaccination are shown in Table 1.
Table 1. Adolescent and Parent Characteristics by Adolescent Permit to Consent to Human Papillomavirus Vaccination in the National Immunization Survey–Teen, 2015-2018a.
| Characteristic | No. (weighted %) | ||
|---|---|---|---|
| Total | Permitted to consent | ||
| Yes | No | ||
| Total | 81 999 (100.0) | 9902 (17.3) | 72 097 (82.7) |
| Adolescent characteristics | |||
| Age at time of survey, mean (SD), y | 15.0 (1.4) | 15.1 (1.4) | 15.0 (1.4) |
| Sex | |||
| Female | 38 942 (49.0) | 4729 (49.0) | 34 213 (48.9) |
| Male | 43 057 (51.0) | 5173 (51.0) | 37 884 (51.1) |
| Hispanic ethnicity | 15 740 (23.5) | 1697 (40.1) | 14 043 (20.0) |
| Races (of individuals reporting non-Hispanic ethnicity) | |||
| Black | 7444 (13.8) | 1202 (9.5) | 6242 (14.7) |
| White | 49 857 (52.6) | 5706 (37.9) | 44 151 (55.7) |
| Other/multiple races | 8958 (10.1) | 1297 (12.5) | 7661 (9.6) |
| Education | |||
| <9th Grade, not in school, or other | 23 486 (27.5) | 2218 (22.5) | 21 268 (28.5) |
| ≥9th Grade | 58 441 (72.5) | 7679 (77.5) | 50 762 (71.5) |
| Had 11-y or 12-y well-child examination | 65 496 (95.1) | 7969 (94.8) | 57 527 (95.2) |
| Health insurance status | |||
| Insured | 77 733 (96.0) | 9460 (97.4) | 68 273 (95.7) |
| Uninsured | 2971 (4.0) | 322 (2.6) | 2649 (4.3) |
| Parent characteristics | |||
| Maternal age group, y | |||
| ≤34 | 6558 (8.6) | 675 (7.0) | 5883 (8.9) |
| 35-44 | 33 953 (43.6) | 4019 (43.2) | 29 934 (43.7) |
| ≥45 | 41 488 (47.8) | 5208 (49.8) | 36 280 (47.4) |
| Maternal education level | |||
| Not college graduate | 44 066 (60.1) | 5265 (64.2) | 38 801 (59.2) |
| College graduate | 37 933 (39.9) | 4637 (35.8) | 33 296 (40.8) |
| Poverty status | |||
| Above federal poverty line | 64 161 (77.7) | 7873 (74.8) | 56 288 (78.3) |
| Below federal poverty line | 14 911 (22.3) | 1699 (25.2) | 13 212 (21.7) |
| Received clinician recommendation | 56 162 (73.2) | 6928 (73.7) | 49 234 (73.1) |
Totals may not sum to the stated sample size because of missing data. Percentages may not sum to 100% because of rounding.
Initiation of the HPV vaccine series was 67.9% for adolescents permitted to consent (n = 6470), compared with 61.4% for those not permitted to consent (n = 44 846; adjusted odds ratio, 1.16 [95% CI, 1.01-1.34]). Vaccine series completion was 53.7% among adolescents permitted to consent (n = 5161) compared with 47.9% among those not permitted to consent (n = 35 473; adjusted odds ratio, 1.06 [95% CI, 0.94-1.21]) (Table 2). In the sensitivity analysis, initiation of the vaccine series remained significantly associated with the ability to consent (adjusted odds ratio, 1.16 [1.01-1.34]).
Table 2. Unadjusted and Adjusted Association Between Being Permitted to Consent to Human Papillomavirus Vaccination and Vaccine Series Initiation and Completion Among Adolescentsa.
| Vaccination status | Permitted to consent, No. (weighted %) | Odds ratio (95% CI) | P value | Adjusted odds ratio (95% CI)b | P value | |
|---|---|---|---|---|---|---|
| Yes | No | |||||
| Logistic regression for vaccine initiation and completion by ability to consent | ||||||
| Initiationc | 6470 (67.9) | 44 846 (61.4) | 1.33 (1.19-1.49) | <.001 | 1.16 (1.01-1.34) | .04 |
| Completiond | 5161 (53.7) | 35 473 (47.9) | 1.26 (1.14-1.40) | <.001 | 1.06 (0.94-1.21) | .35 |
| Sensitivity analysis excluding states with school mandates e | ||||||
| Initiationc | 5328 (67.8) | 42 653 (61.3) | 1.33 (1.19-1.49) | <.001 | 1.16 (1.01-1.34) | .04 |
| Completiond | 4175 (53.6) | 33 618 (47.8) | 1.26 (1.14-1.41) | <.001 | 1.07 (0.94-1.21) | .33 |
Totals may not sum to the stated sample size because of missing data. Percentages may not sum to 100% because of rounding.
Adjusted models control for survey year, teen age, sex, race and ethnicity, education, 11-year or 12-year checkup, health insurance status, poverty status, and mother's age, education, and poverty status, and receipt of clinician recommendation.
Initiation is any number of human papillomavirus vaccine doses greater than 0.
Completion indicates completion of 3 or more doses or 2 or more doses with the first dose before age 15 years. This variable was unavailable for 2015 but was recreated by the authors.
Rhode Island and Virginia were excluded because of school mandates, as was Washington, DC.
Discussion
Laws that permit adolescents to consent to HPV vaccination are either in a scope of laws allowing adolescents to make independent decisions on sexual health, or less commonly, in a more general scope of preventive health inclusive of vaccines.2 Our analysis showed a significant positive association between adolescents being permitted to consent to HPV vaccination by state laws in their location of residence and increased rates of initiation of the vaccine series. This suggests that policies that permit adolescents to consent to HPV vaccination could be an important strategy toward improving vaccine initiation among young adolescents, when the vaccine is likely to be most effective. Given the cross-sectional nature of these analyses, we are unable to establish causality. States with certain characteristics that are associated with immunization rates may also be more or less likely to pass laws permitting adolescents to give consent. However, it is notable that states permitting adolescent consent to HPV vaccinations are highly diverse with respect to geography, population, and demographic variables. Further work is needed to better understand the associations between policies permitting adolescent consent to vaccinations and immunization rates.
References
- 1.Elam-Evans LD, Yankey D, Singleton JA, et al. National, regional, state, and selected local area vaccination coverage among adolescents aged 13-17 years—United States, 2019. MMWR Morb Mortal Wkly Rep. 2020;69(33):1109-1116. doi: 10.15585/mmwr.mm6933a1 [DOI] [PMC free article] [PubMed] [Google Scholar]
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- 3.US Department of Health and Human Services . NIS-Teen data and documentation, 2015-2018. Published January 2020. Accessed July 2020. https://www.cdc.gov/vaccines/imz-managers/nis/datasets-teen.html