Abstract
Background and Objective: The human papillomavirus (HPV) vaccine, launched in 2006, has proven effective at reducing HPV infection rates and preventing HPV-associated cancers. However, less than 60% of adolescents have completed the recommended vaccine series, and the rate is even lower among Hispanic children and adolescents. This study explores the age of initiation within our comprehensive vaccination program in West Texas, Tiempo de Vacunarte.
Methods: This study is a retrospective analysis of HPV vaccine completion among individuals 9 to 17 years old from Tiempo de Vacunarte between June 2015 and February 2018. The program was open to individuals 9 to 26 years old who had at least one prior dose of the HPV vaccine, were uninsured or underinsured, and had a Texas address. The primary outcome was completion of the HPV vaccine series.
Results: A total of 2,380 individuals were enrolled, and this study analyzed a subset of 613 children aged 9 to 17 years; 59.8% completed the vaccine series. Most were female (53.8%) and had parents born in Mexico (75.2%). Children 11 to 14 years old were likelier to complete the vaccine series than other age groups (OR: 2.802, P = .006). Children with parents with higher education and less time residing in the US were likelier to complete the series.
Conclusion: Our study supports advocating for initiating the HPV vaccine at a younger age and completing the series by 14 years old. Multi-component and culturally tailored programs are an effective means to increasing HPV vaccine uptake and decreasing the burden of HPV-associated cancers.
- Cervical Cancer
- Early Medical Intervention
- HPV Vaccines
- Hispanics
- Human Papillomavirus Viruses
- Medically Uninsured
- Minority Health
- Public Health
- Retrospective Studies
- Texas
Introduction
Human papillomavirus (HPV) has over 200 known variants.2 Extensive evidence links HPV to cervical, vaginal, and vulvar cancers in females; penile cancer in males; and anal and oropharyngeal cancers in both sexes.1 The HPV vaccine, approved by the US Food and Drug Administration (FDA) in 2006 has been instrumental in reducing HPV infection rates and preventing HPV-associated cancers.2 A 2-dose vaccine series is recommended for individuals who begin the series between ages 9 and 15. For those who start after age 15, a 3-dose series is advised.1
Texas currently ranks 44th in HPV vaccine initiation and 48th in series completion for those 13 to 17 years old. As of 2017, HPV vaccination uptake varies across Texas.3 Based on a study that looked at 2017 National Immunization Survey (NIS)-Teen data among 13 to 17 years olds in 6 different regions of Texas, the US-Mexico border region of El Paso County had the highest rate of HPV vaccine series initiation at 83% (95% CI; 78% to 88%), which is higher than that of the US.3 El Paso County also had the highest completion rate at 51% (95% CI: 44% to 58%), which was higher than the national rate for 2017 at 48.6%.3
Studies have revealed that the most common barriers to HPV vaccination included lack of knowledge about HPV itself and the vaccine, safety concerns, social stigma, and cost.4–6 Facilitators of uptake are clinician recommendation, perceived risk of HPV, increasing accessibility, reminders, and vaccine benefits.4–6 In addition, the American Academy of Pediatrics (AAP) and the American Cancer Society (ACS) recommend routine initiation of the HPV vaccine at 9 years old, rather than at 11 to 12 years old.7 Data from the NIS-Teen has shown that most individuals initiating the HPV vaccine at 9 to 10 years old completed the series by the time they turned 18 compared with those who began it at 11 or older.8
While existing research has not thoroughly examined HPV vaccination among Hispanic adolescents in rural Texas-Mexico border communities,9–15 this study contributes further by analyzing the age of initiation within our comprehensive Tiempo de Vacunarte (TdV) HPV vaccination program in West Texas. Specifically, we assess the effects of initiating the vaccine series before age 11 and compare HPV vaccine series completion between those who begin before age 11 and those aged 12 years and older.
Methods
Study Design, Setting, and Eligibility
This study is a retrospective analysis of HPV vaccine series completion among individuals aged 9 to 17 using cohort data from TdV between June 2015 and February 2018. Established in 2014 with funding from the Cancer Prevention and Research Institute of Texas (CPRIT), the TdV program is a community-based initiative to reduce the incidence of HPV-associated cancers in West Texas. The program employs culturally tailored, evidence-based strategies to enhance HPV vaccine awareness and uptake among underserved populations. Key components include community outreach, health education, navigation to health care services facilitated by a community health worker (CHW), and the provision of no-cost HPV vaccinations to eliminate financial barriers.
This intervention was conducted in El Paso County, Texas, a region located on the US-Mexico border with an estimated population of 8,404,010 in 2017.16,17 The population is predominantly Hispanic (82.8%), 78.5% of which are of Mexican origin. The region had poverty rates (17%) higher than the national average (11.1%),18 as well as higher uninsured rates (20.6%) compared with Texas (20%) and the nation (18%).18,19 Participants were recruited from multiple community sites, including but not limited to community centers, food banks, health fairs, community colleges, trade schools, school districts, and churches.
Eligible individuals for the TdV program were 9 to 26 years old, had not previously completed the HPV vaccine series (they could have had none or 1 doses if they were 9 to 14 and none, 1, or 2 doses if they were 15 to 17), were uninsured or underinsured, and had a Texas address (a requirement of the funding agency). Parents completed enrollment and informed consent forms for children and adolescents aged 9 to 17. Age criteria were determined using the Advisory Committee on Immunization Practices (ACIP) recommendations for HPV vaccination. The TdV intervention has been described previously.20
Ethical approval for the study was obtained from the Institutional Review Board of Texas Tech University Health Sciences Center El Paso.
Outcomes
The primary outcome measure was HPV vaccine completion. We defined vaccine completion as receipt of 2 doses at least 6 months apart for individuals 9 to 14 years old and receipt of 3 doses over 6 months for those aged 15 to 17.
We also collected data on demographic information as covariates of uptake, including age, sex, parents' level of education, parents' household income, country of birth, and length of residence in the United States. For child participants 9 to 17 years old, this information was collected from the parents or legal guardians; however, it will be referred to as the child participant data.
Sample and Statistical Analysis
During the first grant cycle of the TdV program, 12,645 individuals were approached, and 2,380 were enrolled. Of those enrolled, data from 1,796 unique participants were available for analysis. For purposes of this data analysis focused on the primary outcome of vaccine series completion, individuals included were: 9 to 17 years old and had at least received 1 dose of the HPV vaccine when enrolled. The analysis included a total of 613 participants.
Categorical variables were reported as frequencies and percentages, while continuous variables were summarized using means, standard deviations, medians, and interquartile ranges. Associations between categorical variables were examined using χ2 or Fisher's exact tests. Regression analysis was performed to evaluate the relationship between HPV vaccine completion and demographic factors, with results presented as adjusted odds ratios and 95% confidence intervals.
Results
Among these 613 children, 59.8% (367/613) completed the HPV vaccine series. The majority (54.0%; 331/613) were between 11 and 14 years old, and slightly more were female (53.8%; 330/613). Most children (75.2%; 461/613) had parents born in Mexico, with most of these parents or legal guardians having lived in the US for 13 to 20 years.
Regarding socioeconomic and educational background, 31.3% (192/613) of parents or legal guardians had a high school education or less, and 53.8% (330/613) reported an annual income below $25,000.
Table 1 presents the demographic characteristics by age-group (9 to 10, 11 to 14, and 15 to 17 years). A higher proportion of females was observed in the 9 to 10 (58.3%) and 11 to 14 (54.1%) age groups, while males were more common among the 15 to 17-year-olds (55.8%). The highest HPV vaccine series completion rate was observed in the 11 to 14 age-group at 68.6%, which was statistically significant (P < .001).
Demographic Characteristics of Tiempo de Vacunarte Participants by Age Groups
When comparing HPV vaccination status across demographic characteristics, significant differences were observed by age-group. Children aged 9 to 10 and 15 to 17 were less likely to complete the vaccine series when compared with those aged 11 to 14 (P < .001). Among those who completed the series, their parents were more likely to have lower levels of educational attainment (P = .017). In addition, parents of children who did not complete the series lived in the US longer than parents who completed it (P < .001). See Table 2 for detailed results.
Associations Among Tiempo de Vacunarte Participants Demographics by Human Papillomavirus (HPV) Vaccine Series Completion Status
A regression analysis assessed the association between demographic characteristics and HPV vaccine series completion (Table 3). Children aged 11 to 14 were nearly 3 times more likely to complete the series than other age groups (OR: 2.802; P = .006). Regarding parental or legal guardian education, those with any level of formal education were 5 to 9 times more likely to have their child complete the vaccine series (P-values ranging from <0.001 to 0.004). Conversely, a longer duration of residence in the US by parents or legal guardians was associated with a lower likelihood of series completion (P = .009).
Adjusted Odds Ratios for Tiempo de Vacunarte Participants by Human Papillomavirus (HPV) Vaccine Series Completion Status
Discussion
Our study found that adolescents aged 15 to 17 were the least likely to complete the HPV vaccination series. We hypothesized that initiating the vaccine at a younger age would be associated with higher completion rates. Consistent with this hypothesis, individuals who began the series between ages 11 and 14 had significantly higher completion rates than other age groups. Although initiation at ages 9 to 10 also showed higher completion than initiation at older ages, this difference was not statistically significant. In addition, children whose parents or legal guardians had some level of education and had spent less time residing in the United States were more likely to complete the vaccination series.
A recent retrospective analysis by Goodman et al., using data from the NIS–Teen (2017 to 2020), found that early initiation of the HPV vaccine is associated with higher completion rates by ages 13 and 15.21 However, like our findings, their study showed that starting the series at ages 9 to 10 did not significantly increase the likelihood of completion compared with initiation at ages 11 to 12.21 It is important to note that our analysis assessed completion within the study period and did not track participants aged 9 to 10 through ages 13 or 15. It is reasonable to assume that, given more time and additional opportunities, younger participants may eventually achieve similar completion rates. Our findings reinforce the importance of targeting vaccine efforts before adolescence, aligning with national recommendations for early initiation.19,22
We found that parents with any level of formal education were significantly more likely to have their children complete the HPV vaccination series than those with no formal education. The likelihood of completion was highest for individuals with less than a high school diploma and those with a college or vocational degree. Our findings highlight the complicated relationship between parental educational level and HPV vaccine completion. While some studies have shown higher vaccine completion with more educated parents,18,23 others have found that mothers with less than a high school education are more likely to have their children complete the HPV vaccination series,24 especially among a Hispanic population.25–27 The variation in these findings is likely due to the sociocultural context of the studies, with many of the studies showing that race and ethnicity do play a role in the interaction between educational level and vaccine completion.
Parents of children who did not complete the vaccine series lived in the US longer than those whose children completed it (P < .001), suggesting that acculturation or shifting attitudes over time may influence vaccine decisions. Our results support a previous study by Anderson et al, which found that less acculturated Hispanic mothers were more likely to have their children up to date with vaccines when compared with their more acculturated counterparts.28 This inverse relationship between the length of US residence and vaccine uptake points to acculturation’s competing role in health care, the so-called migrant paradox. Studies show that less-acculturated immigrant parents sometimes maintain higher trust in vaccinations, likely reflecting stronger ties to public health norms from their countries of origin.29,30 At the same time, greater exposure to US societal skepticism and systemic health care barriers (complex, fragmented processes) may erode confidence over time.30 Although our study did not specifically investigate the correlation between parental understanding or attitudes toward the HPV vaccine and vaccine completion rates, previous research conducted by Rutten et al. has addressed this relationship.31 These findings underline the need for nuanced, culturally tailored strategies that leverage community-based trust, rebuild institutional confidence, and simplify health care navigation to support sustained vaccine adherence among immigrant communities.
One limitation of this study is its cross-sectional design, which inherently restricts the ability to establish cause-and-effect relationships. Because the study was conducted in a community along the US-Mexico border with a predominantly Mexican/Mexican-American population, the findings may not be generalizable to other ethnic or geographic groups. It should also be noted that through our program, we did not ask about parental barriers to having their child or adolescent screened, including with sexual health nature of the vaccine, and we did not inquire with the clinicians about their beliefs or practices surrounding the HPV vaccine. In addition, it is worth noting that although this program is continuing to serve El Paso and rural West Texas, funding for vaccine service projects has decreased and overall public vaccine hesitancy has increased.
A key strength of our study is that few others have examined HPV vaccination outcomes within underserved Hispanic subgroups. By capturing data from this underrepresented group, our study contributes valuable insights and emphasizes the need for culturally tailored interventions. Notably, this is the first community-based study to evaluate HPV vaccine initiation and completion among both younger and older children following a comprehensive intervention in a predominantly Hispanic population along the US-Mexico border.
Future studies might focus on a culturally tailored and bilingual positive vaccine campaign emphasizing that the HPV vaccine is a cancer prevention vaccine and has now been in existence for close to 20 years and proven it is safe and effective. There can also be more studies looking at the frequency with which clinicians recommend the HPV vaccine to parents of 9- and 10-year-olds and assess their knowledge of the benefits of initiating the vaccine series at an earlier age.
Conclusion
Given the numerous protective benefits of the HPV vaccine, our study strongly advocates for initiating vaccination at an earlier age and encouraging completion by 14 years old. This requires the combined efforts of public health professionals to educate the community along with clinicians in understanding the critical role they have in recommending the vaccine to parents of children at a younger age. Programs that are multi-component, culturally sensitive, and facilitated by CHWs, such as TdV, have proven to be effective in increasing HPV vaccine uptake and can serve as a model in other similar populations to curb the burden of cervical cancer and other HPV-associated cancers.
Notes
This article was externally peer reviewed.
Funding: All phases of this study were supported by a Cancer Prevention and Research Institute of Texas Grant, PP140211.
Conflict of interest: The authors have no conflicts of interest to disclose.
- Received for publication June 10, 2025.
- Revision received July 28, 2025.
- Accepted for publication August 25, 2025.
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