Provider recommendation remains the strongest influence over a patient’ s decision to receive a vaccine. 13 By evaluating whether two non-mandated vaccines are correlated among a large cohort, it can better guide provider counseling. It was hypothesized that due to similar misconceptions prevalent among the two vaccines, receiving the HPV-9 vaccine may be predictive of whether subjects did or did not receive the COVID-19 vaccine.
MATERIALS AND METHODS
This study was a retrospective chart review of vaccine records among male and female WV adolescents. Adolescent subjects aged 13-16 years were included if they presented to Marshall Health Department of Pediatrics between May 2021 and June 2022 for a well child visit or immunization encounter. Subjects were also only included if they were designated WV residents based on their home ZIP code at the time of their encounter. The time frame of May 2021 to June 2022 was chosen because it was the calendar year following the FDA approval of the COVID-19 mRNA vaccine for adolescents. Ages 13-16 years were chosen because these subjects fell within the age of approval for the COVID-19 vaccine, and this age range would have allowed time for completion of the HPV vaccine series, which is recommended starting at 11 years of age. We included only WV residents to provide a description of the relationship between the COVID-19 vaccine and HPV- 9 vaccine specific to our state. WV also has a statewide immunization information system( WVSIIS) that communicates directly with the electronic health record at Marshall Health. This communication allowed us to capture vaccines given in other settings such as school-based health centers or pharmacies. Prior to study commencement, the study team reviewed multiple patient charts with known pharmacy vaccination to ensure that the health record did capture this data appropriately. During chart review, all study team members imported any additional vaccine information from the WVSIIS. This system did not capture vaccines given out of state.
ICD-10 codes for well child visits and immunization encounters among all Marshall Health pediatric providers were used to compile the dataset for the given age group during the designated year of study. Duplicates and non-WV residents were excluded. Subjects who had more than one visit were included only once. Data were then obtained from the medical record on the subjects’ vaccinations, including dates of HPV-9, Tdap, MenACWY, and COVID-19 vaccinations. This chart review was conducted during fall 2023, which allowed at least a year of follow up for subjects to have completed each vaccine. Data points obtained also included date of birth, gender, ZIP code, and county. Date of birth was used to calculate age at the time of each vaccine( HPV-9, COVID-19, Tdap, and Men- ACWY).
Gender
MenACWY Vaccine
Tdap Vaccine
HPV-9 Vaccine
COVID-19 Vaccine
Female Male
Completed Not Vaccinated
Completed Not Vaccinated
TABLE 1
Completed Series One Dose Only Not Vaccinated
Completed Series One Dose Only Not Vaccinated
The assumption prior to data collection was that Tdap and MenACWY vaccine rates would be high as they are mandated by WV schools. These vaccines therefore served as a quality control for the dataset to ensure that records were complete. Rates of each vaccine among subjects were calculated along with ages when vaccines were given. Proportions of vaccine uptake were compared between male and female adolescents. To determine the relationship between HPV-9 and COVID-19 vaccines, we also compared the proportion of patients who did not receive the COVID-19 vaccine among subjects who did and did not receive the HPV-9 vaccine. Descriptive statistics were used for demographic and overall vaccine uptake. Chi-square statistics were used to compare all proportions, and the odds ratio( OR) was calculated by using HPV-9 as the exposure and COVID-19 vaccination as the outcome.
RESULTS
There were 1,484 subjects who met inclusion criteria with a well child visit or immunization encounter during the designated study period. The cohort was closely split by gender with 736( 49.6 %) females and 748( 50.4 %) males. ZIP code data demonstrated there were 745( 50.2 %) subjects who resided in Cabell County, 343( 23.2 %) in Wayne County, 123( 8.3 %) in Putnam County, 87( 5.9 %) in Lincoln County, and 60( 4.0 %) in Kanawha County. The remaining 8.5 % of subjects were distributed among 10 other surrounding WV counties within the Marshall Health service area.
Table 1 demonstrates overall vaccine rates for the cohort. As expected, both Men- ACWY and Tdap had high rates of uptake, with 97.5 % and 96.6 %, respectively, receiving these vaccines. HPV-9 and COVID-19 vaccine rates were lower. For the HPV-9 vaccine, 70.1 % of the cohort had completed the HPV-9 series, 11 % received only one dose, and 18.9 % were unvaccinated. Of the cohort, 54.2 % had received both COVID-19 vaccines, 6 % had received one dose, and 39.8 % remained unvaccinated.
N = 1484(%) 736( 49.5) 748( 50.4)
1447( 97.5) 37( 2.5)
1434( 96.6) 50( 3.4)
1040( 70.1) 164( 11) 280( 18.9)
804( 54.2) 89( 6) 591( 39.8)
Demographic Data and Overall Vaccine Uptake Among a Cohort of 1,484 Adolescent Subjects
West Virginia Medical Journal • December 2025 • 25