Demographic disparities, temporal trends, and geographic patterns of HPV vaccination on Long Island, New York: A comprehensive analysis of immunization registry data (2012–2023)

ABSTRACT

The Advisory Committee on Immunization Practices (ACIP) advised vaccinating children, adolescents and young adults against Human Papillomavirus (HPV) in 2006, aiming to prevent HPV-related cancers and genital warts. As HPV vaccination rates remained low even 10 years after it was introduced, understanding vaccination patterns is essential for informing targeted public health interventions. This study explores the demographic disparities (age, gender, race and ethnicity), temporal trends, and geographical patterns of HPV vaccine administration by analyzing large-scale immunization registry data for Long Island (LI) (Nassau and Suffolk Counties), New York (NY). The vaccine registration data retrieved from the New York State Immunization Information System (NYSIIS) was used to assess the HPV vaccine administration rate from 2012 to 2023. Patients’ demographic information and regional variations were evaluated to identify the disparities between different subgroups. The HPV vaccination rate among LI children ages 9 to 13 demonstrates a growth of 284.43% from 2012 to 2019 and a slight decrease of 5.04% around 2020. Around 68.07% of individuals received their first dose before their 15^th birthday and 24.95% of them received their second dose timely, given 6 to 12 months after the first dose. Spatially, eastern LI consistently holds a higher HPV vaccination rate than northwestern LI due to regional disparities. The rising trend in HPV vaccination coverage on LI with a modest drop around 2020 indicates the likely impact of COVID-19 pandemic. This study suggests the need for increased focus on regions with lower vaccine uptake rates for preventing HPV-related cancers.

Introduction

Human Papillomavirus (HPV) infection, which is the most common sexually transmitted infection, causes approximately 33,700 cases of cancer every year in the United States.^1–3 The HPV vaccine was designed to prevent infection by certain types of HPV, which can lead to six types of cancer (anal, cervical, oropharyngeal, vulvar, vaginal, and penile) and genital warts. It is one of the most effective ways to prevent HPV-related diseases.^4,5 The vaccine is administered through a series of injections. In the United States, the HPV vaccine is widely available and recommended for adolescents and young adults.⁶ Various campaigns and initiatives have been launched to increase awareness and uptake of the vaccine. ⁷ For example, the American Cancer Society’s “Mission: HPV Cancer Free” campaign aims to eliminate cervical cancer in the U.S. within 40 years by achieving an 80% HPV vaccination rate among 13-year-olds by 2026 and promoting continued screening and treatment for cervical pre-cancers.⁴ Additionally, the NYSDOH/Health Research Inc.‘s Cancer Prevention in Action (CPiA) Program, which was awarded to Stony Brook Cancer Center Community Outreach and Engagement Office (COE) to support efforts in increasing HPV vaccination rates in Suffolk and Nassau Counties to ultimately reduce HPV-related cancer risk on LI. In 2022, 38.6% of children aged 9 to 17 had received one or more HPV vaccine doses.⁸ Additionally, school-based vaccination programs and community efforts have been utilized to reach adolescents globally and are standard in many countries.^9,10

The HPV immunization schedule followed a recommended protocol maximizing long-term protection against HPV-related diseases. Guidelines established by NYSDOH supported the ‘Start at 9’¹¹ initiative by the National Human Papillomavirus Vaccination Roundtable, promoting the recommendation for routine HPV vaccination to commence ages 11 to 12 starting as early as age 9.^4,12 When the HPV vaccine is given to individuals before their 15^th birthdays, only two doses, separated by a minimum of 6 months, are required to complete the vaccination series. However, for those who initiate the HPV vaccination series at age 15 or older, or individuals age 9 to 26 with a weakened immune system, three doses are necessary for full protection. In the case of three doses, the second dose should be administered 1 to 2 months after the first, and the third dose should be given at least 6 months after the initial dose.¹³ The minimum interval between the second and third doses is 12 weeks, with 5 months between the first and third doses. Vaccination schedules may be used by healthcare providers to give parents and patients recommendations about the importance of completing the full series for maximum benefit.^14,15

In New York, like in many other states, efforts have been made to ensure vaccine accessibility through healthcare providers, clinics, and public health programs. The New York State (NYS) government provided various measures to cover the expenses of HPV vaccination to promote its uptake among young people.¹⁶ Both women’s and men’s HPV vaccination coverage in NYS is higher than the average HPV vaccination rate nationally according to the official report released by NYSDOH in 2020.¹⁷

The purpose of this study is to better understand the HPV vaccination rate by analyzing demographic disparities, temporal trends, and geographic patterns on Long Island (LI). LI has a diverse population with varying socio-economic backgrounds, cultural norms, and healthcare access, which can profoundly influence vaccination rates.^17,18 The Bureau of Immunization within the NYSDOH is dedicated to enhancing the well-being of children in New York State by minimizing or eradicating vaccine-preventable diseases that impact the state’s youth.^19,20 This helps epidemiologic researchers and health providers understand how interventions and demographics affect vaccine uptake and lets them tailor public health efforts to LI’s specific needs.²¹ Additionally, analyzing geographic patterns of vaccination may help identify the impact of socioeconomic differences, cultural norms, and healthcare access on HPV vaccination rates. Long Island (New York) provides a unique setting for studying HPV vaccination due to its diverse socioeconomic landscape, racial and ethnic disparities, healthcare accessibility challenges and the impact of the COVID-19 pandemic.²² Long Island has historically exhibited lower rates of HPV vaccine administration compared to state and national averages. According to the NYS Prevention Agenda County Dashboard,²³ vaccine uptake in this region has lagged behind other areas, highlighting a persistent gap in preventive care. By analyzing local patterns and trends, our study provides critical insights into the underlying factors contributing to these disparities. Understanding these region-specific barriers is essential for effective targeted interventions that can improve vaccination rates. Therefore, understanding demographic disparities, temporal trends, and geographic patterns on Long Island enables a comprehensive understanding of regional dynamics and facilitates targeted public health strategies to improve vaccine uptake and reduce the burden of HPV-related cancer on Long Island.

Methods

Study sample

This study utilized patient vaccination data from NYSIIS (New York State Immunization System), managed by NYSDOH, collecting immunization records for individuals since 2008 to prevent vaccine-preventable diseases among children in the state.¹⁹ To protect patient privacy, the NYSDOH data presents case counts associated with zip codes rather than individual addresses²⁴ Our research was centered on zip codes belonging to Long Island (LI) (Nassau and Suffolk Counties).²⁴

Two datasets were obtained from NYSIIS: one dataset of all HPV vaccination records and one dataset for Tdap. Tdap vaccination records are used as a reference for measuring HPV vaccination rate, as discussed later. Only people who received either the HPV or the Tdap vaccination or both were included in our analysis. In total, 2,173,576 patients’ visit records, and 1,120,113 unique patients (473,995 hPV vaccinated patients) were included in our analysis. We also utilized patient-level information, including demographics (Age, Zip code, County, Gender, Race, Ethnicity), vaccination months and years.

In New York State, children enrolled in daycare as well as those in pre-K through 12th grade are obligated to receive all necessary vaccines including Tdap doses according to the recommended timetable to be eligible for school attendance.²⁵ In our study, we used the number of school-aged children who got the Tdap vaccination as the reference value to calculate the HPV vaccination rate. We used the number of children aged 9–13 years who received the HPV vaccination as the numerator, and the number of children aged 9–13 years who received either vaccination with HPV alone, HPV and Tdap, or Tdap alone as the denominator.

Statistical analysis

Patients demographic analysis

The patient information was aggregated by the unique client ID and sorted by the vaccination year and month. Only initial visits were counted if a patient has multiple visits. In our study, we utilized patient-level data from 2008 to 2023. Our target group consisted of children aged 9 to 13. To ensure the accuracy and completeness of the denominator in our vaccine rate calculation, we exclude data from 2008 to 2011. Given that the starting year of the HPV and Tdap vaccines is different, some children may have received it prior to 2008, but those records would not be captured in our dataset. If these children received the HPV vaccine after 2008, they would be included in the numerator while potentially being excluded from the denominator, leading to an overestimation of the HPV vaccine rate. By restricting the analysis to 2012 and beyond, we ensure that all children aged 9–13 have comprehensive vaccine records within the study period. This approach mitigates selection bias and provides a more reliable estimate of vaccine uptake. A comprehensive analysis was conducted to analyze gender, race, and ethnic disparities among those vaccinated patients.

Temporal analysis over 2012 to 2023

All the patient-level data were aggregated by the vaccine year and month from the data to visualize the trend and seasonality. In this section, if a person received multiple doses, only the initialized time was used in the temporal analysis. The number of children between ages 9 and 13 who either received the Tdap or the HPV vaccination or both in a specific year were counted as the denominator and the numerator was the number of children from 9–13 who received the HPV vaccination. The results include HPV vaccination rates for LI as well as individual county rates for Suffolk and Nassau Counties.

Geographical spatial analysis

We visualized the zip code-level spatial distribution of the HPV vaccination rate calculated by the formula provided in previous sections using geographical maps. The shade of color in each block represents the rate of HPV vaccination. All maps were generated using ArcGIS Desktop 10.5 (Esri, Redlands CA).

Approval was obtained from the NYSDOH and a Stony Brook University IRB before dataset acquisition and analysis (838962_MODCR008). This study utilized de-identified data from the New York State Immunization Information System (NYSIIS), a state-managed immunization registry that contains confidential Protected Health Information (PHI). Patient consent was not required because all personally identifiable information was removed prior to data access, ensuring compliance with data privacy regulations. All study analyses were completed between 2023 and 2024.

Results

Demographic disparities for HPV vaccination initiation

Table 1 provides an overview of patient demographics, including various groups categorized by demographics. Each row in the table represents a distinct demographic category, while columns display the number of HPV-vaccinated patients in that group. The p-values in the table (p < .0005) represent the results of an OLS regression analysis, assessing the linear trend in HPV vaccination rates over the years within each demographic group. The table indicates that there is a slightly lower number of female patients compared to male patients. In our database, the largest group as defined by race is white, followed by Black and Asian (all p < .0005) indicating a statistically significant increasing trend in vaccination rates for these groups over time.

Table 1.

Summary of aggregation information of HPV vaccination patients on the Long Island. (the patients from the entire NYSIIS database)¹.

														p value5
		2012	2013	2014	2015	2016	2017	2018	2019	2020	2021	2022	2023	Linear	Overall6
Gender	Male	20574	38493	56711	77367	99946	120951	142650	163788	179135	193555	209654	225007	<0.0005	<005
	Female	55221	70823	86802	106035	126958	146873	166948	187044	202339	216664	232859	248334	<0.0005	<0.05
Age	9–132	16458	23004	28215	36383	44374	49557	54729	58983	56735	52808	51848	51522	<0.0005	<0.0005
	14–25	59331	86296	115183	146644	181202	214563	246876	277885	302238	322171	338127	348376	<0.0005	<0.5
Race and Ethnic	White	32635	49774	66838	86873	109218	130939	152995	174070	190051	203714	218956	233244	<0.0005	<0.05
	Black	6643	9529	12635	16727	21117	25031	28954	32860	35569	38436	41532	44677	<0.0005	<0.0005
	Asian	3990	5803	7830	10642	13637	16675	20017	23285	25957	28451	31613	34801	<0.0005	<0.0005
	Hispanic	14329	21043	29631	39846	51594	61855	72568	84262	92393	101611	112155	122192	<0.0005	<0.0005
	Non-Hispanic	38598	58515	78026	101732	127471	152483	177657	201188	219371	234853	252642	269436	<0.0005	<0.5
Total			75954	109540	143808	183751	227304	268268	310072	351339	381998	410773	443121	473995	<0.0005

^aThe absolute numbers here represent the number of individuals in the specific group with one or more HPV vaccine doses.

^bChildren ages 9- to 13-year-old are the targeted population studied in this paper.

^cHPV vaccination is not recommended for everyone older than age 26 years.

^dThe numbers in the parentheses show the newly added patients who initiated the HPV vaccination during that year.

^eThe OLS regression was used to test the linear trend of each yearly rate.

^fThe overall p-values are obtained from an F-test, which evaluates whether there are significant differences in variance among the groups compared to the total population.

Figure 1 illustrates the age distributions of different groups of patients receiving the HPV vaccination. The histogram reveals that most patients receive their first dose between 10 and 14 years of age. There is a slight variation between genders, with females (age 10–11) initiating vaccination slightly earlier than males (age 11 to 12). Hispanic individuals tend to start their HPV vaccination series sooner than non-Hispanic individuals.

Figure 1.

Age distributions of patients who received one or more doses of HPV vaccine by gender, race, and ethnicity.

Demographic disparities and temporal trends of doses series completeness

Figure 2 indicates the HPV vaccine initiation rate on Long Island among children aged 9–13 years from 2012 to 2023. The overall rate went up by 284.43% from 2012 to 2019 and is followed by a slight decline (5.04%) in 2020 and 2021. This may have been caused by the COVID-19 pandemic: the rate rose smoothly from 2021 to 2023, when the acute phase of the pandemic ended. This trend was evaluated via ordinary least squares (OLS) regression and emphasizes the significance of the linear trend (p < .0005).

Figure 2.

HPV vaccine initiation rate among 9- to 13-year-old children in Nassau and Suffolk Counties, New York. The rate here was calculated by the number of children who already initialized the HPV vaccination divided by the number of children either receive the HPV vaccination or tdap vaccination.

In Figure 2, subfigure A, both males and females experienced a similar trend but the starting point for boys is slightly lower than girls at the outset. The U.S. Food and Drug Administration (FDA) approval of HPV vaccination for girls began in 2006, while it was recommended for boys until 2011.^5,26 This earlier approval for girls could have led to a delay in vaccination initiation among boys compared to girls. After 2019, however, this gap has been narrowing annually, with vaccination rates for both girls and boys becoming nearly consistent.” In Figure 2, subfigures B and C, Nassau and Suffolk counties show similar trends from 2012 to 2023 (p > .05). Disparities among different racial and ethnic groups are shown in subfigure D: non-Hispanic and white people’s HPV vaccination rates are consistently lower than people who identified themselves as Black and Hispanic among those children aged 9–13 years.

Regarding the completeness of the whole vaccination series, the nested pie chart A in Figure 3 represents the dose schedule among all the HPV vaccinated patients in our database. According to the CDC’s HPV immunization schedule guideline, we divided all the patients by the age at the first HPV vaccine dose. Initial age <15 and initial vaccination after the 15th birthday were represented by the red and blue parts of the figure. Approximately 45.1% of the first group completed the recommended doses in 12 months and 37% of the second group finished their whole 3-dose series. Adolescents receiving their first dose before age 15 were more likely to finish than teens starting later, with over 82.58% of the under-15 group completing the series compared to about 45.75% of the over-15 group. Figure 3, Subfigures B and C illustrate the initiation rate and completion rate disparities among gender, race, and ethnicity groups. The numbers on the bars represent the portion of people who completed the HPV vaccine series compared to those who initiated the HPV vaccination schedule. Of those who started the vaccine, about 70.82% of them completed the full series. Girls finished the vaccine series slightly more often than boys and Asians had the highest completion rate at nearly 75%.

Figure 3.

The completeness of the HPV vaccinated individuals on the Long Island, New York State, 2012–2023. The figures are generated according to the CDC HPV vaccination guidelines. Figure 4 Geographical maps of HPV vaccination rates on Long Island, New York (Nassau and Suffolk Counties) among children ages 9–13 by zip code. The rate was calculated by the number of children receiving one or more HPV vaccine dose divided by the number of children who received HPV, Tdap or both vaccines.

Geographic patterns at zip code level

We chose 8 typical years of geographical maps in Figure 4 to represent the spatial distribution of the HPV vaccination rate on Long Island (LI) among adolescents aged 9–13 years. OLS regression was used to assess the linear trend, and the results indicate that over 82% of zip code areas exhibit a statistically significant trend (p < .05), confirming the presence of a linear pattern in the yearly trends. For the overall difference, we used the F-test to determine whether there are significant differences in variance among the yearly vaccinated populations in each group. If there are significant differences among the group’s variance and total variance, the test will yield a low p-value. The HPV vaccination rate on the eastern side of LI consistently exceeds that of the western side. Riverhead (zip code 11,901) had the highest HPV vaccination rate area on LI. This may be due to various factors such as socioeconomic status, healthcare access and awareness, culture and social norms, and media influence. Notably, Riverhead has a higher proportion of minority populations, who tend to have higher HPV vaccination rates compared to other groups.²⁷

Figure 4.

Geographical maps of HPV vaccination rates on Long Island, New York (Nassau and Suffolk Counties) among children ages 9–13 by zip code. The rate was calculated by the number of children receiving one or more HPV vaccine doses divided by the number of children who received HPV, Tdap or both vaccines.

Discussion

This research fills the knowledge gaps in HPV vaccine research by identifying demographic, temporal and geographic disparities on Long Island (LI) by applying epidemiological and data analytics techniques to assess the geographic, temporal, and personal demographics of HPV-vaccinated individuals. It highlights racial, ethnic, and gender-based disparities, tracks the impact of COVID-19 on vaccination trends, and reveals regional variations linked to socioeconomic factors. The study provides data-driven insights for targeted public health interventions and serves as a model for analyzing vaccine uptake in diverse populations.

Temporally, the HPV vaccination rate across LI has gradually increased over the past decade with a slight drop during the COVID-19 pandemic. This trend aligns with national increases in HPV vaccination rates, as reported by the New York State Department of Health and the Centers for Disease Control and Prevention among children.^8,17,28 LI child HPV vaccination rate rose each year until 2019, which had the highest rate at about 44.99%. However, when COVID-19 hit in early 2020, the vaccination rate dropped slightly (a 5.04% decrease from 2019 to 2021). Since then, the vaccination rate has gradually recovered but hasn’t reached 2019’s maximum rate yet.

Beyond these temporal trends, we also found that there are disparities in the HPV vaccination rates across different racial and ethnic groups. For example, Hispanic people had a consistently higher vaccination rate than other ethnicities. Efforts to improve vaccination awareness and access are crucial for all racial and ethnic groups.

Geographically, eastern Long Island has better coverage than western Long Island, where 82% of ZIP codes showed a significant linear trend in vaccination rates based on OLS regression analysis. These findings support the continued encouragement of early HPV vaccination and highlight the need for targeted efforts on LI’s North Shore, where fewer school-aged adolescents are getting vaccinated. This geographic disparity may be influenced by several factors, including socioeconomic differences, healthcare access, and local cultural or demographic characteristics. Future research should further investigate these potential factors to inform more effective, community-specific interventions. Our study adds to what we know from other recent studies in the past decade. The New York State Department of Health releases cancer-related statistics including HPV-related cancer and HPV vaccination every five years, helping us track medium and long-term relationships between HPV vaccination and disease incidence rates.^17,28,29 In 2016, Vielot et al. found that older boys and adolescents living in rural areas didn’t get the HPV vaccine at the same rate as other vaccines like Tdap or MenACWY.³⁰ Our findings are similar: boys’ and especially older children’s HPV vaccination rates are both quite lower than girls’. Thompson el al. focused on college students and emphasized that work is needed to increase women’s HPV vaccination rates within the said demographic.³¹ This aligns with our finding that HPV vaccine series completion is lower among individuals who initiate vaccination at an older age compared to those who start at a younger age. Chen et al. and his team utilized the commercial insurance database in the US and indicated that HPV vaccination coverage among insured children still needs more efforts to improve.^32,33 This is like what we saw with different places in Long Island – some areas and some groups required more effort to increase the uptake of the HPV vaccination. Lastly, Sonawane et al. found that the primary reason for patients not initiating the HPV vaccine are safety concerns.³⁴ To improve HPV vaccination rates, especially among unvaccinated teens on LI, targeted interventions are needed, including school-based initiatives, provider recommendations, and outreach programs in communities with lower uptake. Addressing these challenges is particularly important for LI, as both Suffolk and Nassau counties’ vaccination rates have not met the New York State and (Priority Area) PA objectives, highlighting the need for more focused public health efforts on LI.²³ We also need to increase intervention efforts for unvaccinated teens and work to correct the false information spreading on social media that greatly influences public opinion.³⁵

Limitations of this study

One limitation of our study pertains to the calculation of HPV vaccination rates among individuals aged 9 to 13 years old. Our analysis relies on using the number of patients who have received the HPV or Tdap vaccination or both as the denominator for calculating HPV vaccination rates within this age group. However, it’s important to note that this denominator may not accurately represent the total population within the 9 to 13 age range. Additionally, it is possible patients may have received the Tdap vaccine in other states but received the HPV vaccine in New York State, leading to potential discrepancies in our calculations. These factors highlight the need for cautious interpretation and consideration of alternative methodologies for accurately assessing HPV vaccination rates among adolescents.

Another limitation of our study is the potential impact of population migration between the years 2012 and 2023, which falls outside the scope of our control in this experiment. Population migration, whether internal or external, can influence the composition and characteristics of the population under study. Individuals may relocate to different regions or countries for various reasons, such as job opportunities, economic factors, or personal circumstances, leading to changes in the demographics of the population. This demographic shift can introduce bias and confound the interpretation of our findings, particularly when assessing long-term trends in HPV vaccination rates. Moreover, migration patterns may vary across different demographic groups, potentially affecting the representation and generalizability of our study results. Therefore, while our study provides valuable insights into HPV vaccination patterns within a specific timeframe, it is essential to acknowledge the limitations imposed by population migration and consider its potential impact on the validity and reliability of our findings.

Conclusion

In conclusion, our study provides valuable insights into the HPV vaccination geographical patterns and temporal trends among adolescents aged 9 to 13 years old on Long Island, NYS. We analyzed several aspects to reveal the user profiles of the HPV vaccination patients and exhibit the yearly trend of the HPV vaccination rate from 2012 to 2023. Ultimately, our study promotes public health and advance our understanding of HPV vaccination practices among adolescents.

In future research, analysis of HPV vaccination trends and patterns could be analyzed in smaller geographic units, such as at the census tract level. This could help us learn more about what is happening in specific communities. We can also enlarge our research scale to the whole New York States. This way, we could obtain a better understanding of HPV vaccine uptake in both cities and rural areas. Our methodology provides a great opportunity to assist researchers, health providers, and physicians in understanding the demographic disparities, temporal trends, and geographic patterns of HPV vaccination on Long Island. This study would inform adaptive strategies for policymakers and healthcare providers to address the need for HPV vaccine uptake promotion and to better understand the pandemic’s effect on HPV-related health outcomes.

Biography

Fusheng Wang is a Professor at Department of Biomedical Informatics and Department of Computer Science at Stony Brook University. He received the Ph.D. in Computer Science from University of California, Los Angeles, and M.S. and B.S. in Engineering Physics from Tsinghua University. Prior to joining Stony Brook University, he was an Assistant Professor at Emory University. He was a research scientist at Siemens Corporate Research (Princeton, NJ) before joining Emory University. His research covers Spatial Big Data Management, GIS, Medical Imaging Informatics, AI in Healthcare, Population Health and Opioid Epidemic Research, and Assistive Technologies.

Funding Statement

This work was supported by the population science seed grant from Stony Brook Cancer Center.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Dissemination to participants and related patient and public communities

There are no plans to disseminate the results of the research to study participants or the relevant patient community.

Role of the funder/sponsor

The funder provides the resources to conduct the study.