Estimating vaccination coverage: validity of household-retained vaccination cards and parental recall

Public health programs rely on household-survey estimates of vaccination coverage as a basis of programmatic and policy decisions; however, the validity of estimates derived from household-retained vaccination cards and parental recall has not been thoroughly evaluated. Using data from a vaccination coverage survey conducted in the Western Pacific's Northern Mariana Islands, we compared results from household data sources to medical record sources for the same children. We calculated the percentage of children aged 1, 2, and 6 years who received all vaccines recommended by age 12 months, 24 months, and for school entry, respectively. Coverage estimates based on vaccination cards ranged from 14% to 30% in the three age groups compared to 78-91% for the same children based on medical records. When cards were supplemented by parental recall, estimates were 51-53%. Concordance, sensitivity, specificity, positive and negative predictive values, and kappa statistics generally indicated poor agreement between household and medical record sources. Household-retained vaccination cards and parental recall were insufficient sources of information for estimating vaccination coverage in this population. This study emphasizes the importance of identifying reliable sources of vaccination history information and reinforces the need for awareness of the potential limitations of vaccination coverage estimated from surveys that rely on household-retained cards and/or parental recall.     

A comparison of parent and provider reported influenza vaccination status of adolescents

Objective

To compare parent and provider reported influenza vaccination status among adolescents.

Methods

Data from the 2009 National Immunization Survey-Teen (NIS-Teen) were analyzed. The NIS-Teen is a nationally representative random-digit-dialed telephone survey of households with adolescents 13–17 years at the time of interview, followed by a mail survey to the adolescent's vaccination providers to obtain provider-reported vaccination histories. During the interview a parent or guardian was asked if the adolescent had received an influenza vaccination and whether their response was based upon recall only or from consulting a parent-held vaccination record (i.e., shot card) with recall of additional vaccinations not recorded on the shot card. Parent-reported influenza vaccination status was compared with provider-reported vaccination status by calculating various validity measures (sensitivity, specificity, positive predictive value [PPV], negative predictive value [NPV], and kappa), overall and stratified by several demographic characteristics. In the main analysis, provider-reported vaccinations were considered the gold standard. To evaluate the completeness of provider-reporting, we conducted additional analysis that also considered vaccinations reported by parents from the shot card or reported received in a non-medical setting as “true” vaccinations.

Results

During the 2008–2009 season, influenza vaccination coverage among adolescents based on provider report was 11.3%. Based on parent report, influenza vaccination coverage was 21.7%. Twenty-two percent of parents retrieved and referred to a shot card during the interview. In the shot card group, provider versus parent reported coverage was 12.5% versus 18.2% while among the recall only group coverage was 10.9% versus 22.7%, respectively. Overall, compared to provider report as the gold standard, parental report of influenza vaccination had a sensitivity of 86.7%, a specificity of 86.2%, a positive predictive value (PPV) of 43.1%, and a negative predictive value (NPV) of 98.0%. Among the shot card group, of vaccinations reported either by provider or by parent reading vaccination off shot card, only 66% were reported by providers. In the shot card group, the “true” vaccination level (16–17%) was closer to the parent reported coverage when it was assumed that vaccinations read by the parent from a shot card but not reported by a provider were considered true vaccinations. Overall, assuming that providers reported 64% of “true” vaccinations, sensitivity increased to 91%, specificity to 93%, and PPV to 71%.

Conclusions

Overall estimated influenza vaccination coverage was more than ten percentage points higher based on parental report than on provider report, with the difference between provider and parent report greater among the recall only group. The two estimates are closer for those with shot cards, but few parents utilized shot cards in our study and most national surveys do not ask parents to consult shot cards when responding about their adolescent's vaccination. The actual vaccination coverage of adolescents studied is likely between coverage estimates obtained from parent report and provider report.     

Validity of maternal recall for estimating childhood vaccination coverage – Evidence from Nigeria

BackgroundVaccination coverage surveys in low- and middle-income countries typically estimate vaccination coverage using data from vaccination cards, parental recall, or a combination of the two. However, these surveys are often complicated by the pervasive absence of vaccination cards, forcing researchers to rely on parental recall. We assessed the validity of mothers’ recall against home-based vaccination cards using data from a community-based household survey in Nigeria.MethodsA cross-sectional survey of 1,254 mothers of children aged 12–23 months was performed in Enugu State, Nigeria in July 2020. Data on vaccination status for BCG, OPV, DPT, Measles, Yellow fever, and Vitamin A supplement were collected using two data sources: home-based vaccination cards and mothers’ recall. We evaluated the level of agreement between the two data sources; estimated the sensitivity and specificity of mothers’ recalls; and computed multivariable regression models to identify socio-demographic factors associated with mothers’ recall bias.ResultsOut of 1,254 mothers interviewed, 578 (46.1%) mothers with vaccination cards were included in this analysis. Vaccination coverage levels were generally similar across data sources, though recall-based data generally underestimated the coverage. The level of agreement between the two data sources was high (≥91.0% for all vaccine types) with recall bias due to under-reporting generally higher than recall bias due to over-reporting. The sensitivity of parental recalls was high for all vaccine types, while the specificity was low across vaccine types. Across all vaccines, mothers recall bias was significantly associated with the rural residence and not receiving postnatal care.ConclusionIn the absence of vaccination cards, mothers’ recall of their children’ vaccination status for BCG, OPV, DPT, Measles, Yellow fever and Vitamin A is a valid instrument for estimating childhood vaccination coverage in this setting in Nigeria. However, additional research is needed to confirm these findings at higher sub-national and national levels.     

Association between provider recommendation and influenza vaccination status among children

BackgroundProvider recommendation is associated with influenza vaccination receipt. The objectives of this study were to estimate the percentage of children 6 months–17 years for whom a provider recommendation for influenza vaccination was received, identify factors associated with receipt of provider recommendation, and evaluate the association between provider recommendation and influenza vaccination status among children.MethodsNational Immunization Survey-Flu (NIS-Flu) parentally reported data for the 2013–14, 2014–15, and 2015–16 seasons were analyzed. Tests of association between provider recommendation and demographic characteristics were conducted using Wald chi-square tests and pairwise comparison t-tests. Multivariable logistic regression was used to determine variables independently associated with receiving provider recommendation and the association between provider recommendation and influenza vaccination status.ResultsApproximately 70% of children had a parent report receiving a provider recommendation for influenza vaccination for their child. The strongest association between receipt of provider recommendation and demographic characteristics was with child’s age, with younger children (6–23 months, 2–4 years, and 5–12 years) being more likely to have a provider recommendation than older children (13–17 years). In addition, children living in a household above poverty with household income >$75,000 were more likely to have a parent report receipt of a provider recommendation than children living below poverty. Children with a provider recommendation were twice as likely to be vaccinated than those without.ConclusionsThis study affirms the importance of provider recommendation for influenza vaccination among children. Ensuring that parents of all children receive a provider recommendation may improve vaccination coverage.     

Issues and considerations in the use of serologic biomarkers for classifying vaccination history in household surveys

Accurate estimates of vaccination coverage are crucial for assessing routine immunization program performance. Community based household surveys are frequently used to assess coverage within a country. In household surveys to assess routine immunization coverage, a child's vaccination history is classified on the basis of observation of the immunization card, parental recall of receipt of vaccination, or both; each of these methods has been shown to commonly be inaccurate. The use of serologic data as a biomarker of vaccination history is a potential additional approach to improve accuracy in classifying vaccination history. However, potential challenges, including the accuracy of serologic methods in classifying vaccination history, varying vaccine types and dosing schedules, and logistical and financial implications must be considered. We provide historic and scientific context for the potential use of serologic data to assess vaccination history and discuss in detail key areas of importance for consideration in the context of using serologic data for classifying vaccination history in household surveys. Further studies are needed to directly evaluate the performance of serologic data compared with use of immunization cards or parental recall for classification of vaccination history in household surveys, as well assess the impact of age at the time of sample collection on serologic titers, the predictive value of serology to identify a fully vaccinated child for multi-dose vaccines, and the cost impact and logistical issues on outcomes associated with different types of biological samples for serologic testing.     

Maternal recall error of child vaccination status in a developing nation.

In the absence of vaccination card data, Expanded Program on Immunization (EPI) managers sometimes ask mothers for their children's vaccination histories. The magnitude of maternal recall error and its potential impact on public health policy has not been investigated. In this study of 1171 Costa Rican mothers, we compare mothers' recall with vaccination card data for their children younger than 3 years. Analyses of vaccination coverage distributions constructed with recall and vaccination-card data show that recall can be used to estimate population coverage. Although the two data sources are correlated (r = .71), the magnitude of their difference can affect the identification of the vaccination status of an individual child. Maternal recall error was greater than two doses 14% of the time. This error is negatively correlated with the number of doses recorded on the vaccination card (r = -.61) and is weakly correlated with the child's age (r = -.35). Mothers tended to remember accurately the vaccination status of children younger than 6 months, but with older children, the larger the number of doses actually received, the more the mother underestimated the number of doses. No other variables explained recall error. Therefore, reliance on maternal recall could lead to revaccinating children who are already protected, leaving a risk those most vulnerable to vaccine-preventable diseases.     

Routine immunization coverage in Pakistan: a survey of children under 1 year of age in community-based vaccination areas

Pakistan is one of two countries in which poliovirus remains endemic. Considering the high number of children born every year, reaching and vaccinating new birth cohorts by improving routine immunization coverage in children <1 year of age is crucial to halting virus transmission. In 2015, a community-based vaccination (CBV) strategy, using local community members to enhance vaccine acceptance and improve routine immunization service delivery, was introduced in areas of Pakistan that have never interrupted poliovirus transmission. In order to assess progress towards improving routine immunization, we performed house-to-house immunization surveys across ten CBV areas in 2017 and 2018. In each household, we determined age-appropriate routine antigen coverage for children <1 year of age based on vaccination card and caregiver recall. We surveyed 5,499 and 5,264 children in 2017 and 2018, respectively. Overall, coverage of inactivated poliovirus vaccine (IPV) at 14 weeks of age was 32% in 2017 and 39% in 2018 based on vaccination card and recall. Across the surveyed areas, coverage ranged from 7% in Killa Abdullah to 61% in Peshawar in 2018. Oral poliovirus vaccination coverage decreased with successive vaccination visits, ranging from 66% for the birth dose to 42% for the 14-week dose in 2018. No area reached the target of 80% coverage for any routine antigen. Our findings highlight the need for concerted efforts to improve routine immunization coverage in these critical areas of wild poliovirus transmission.     

Rural,urban, and suburban differences in influenza vaccination coverage among children

Influenza vaccination is the primary way to prevent influenza, yet influenza vaccination coverage remains low in the United States. Previous studies have shown that children residing in rural areas have less access to healthcare and lower vaccination coverage for some vaccines. Influenza vaccination coverage among children 6 months–17 years by rural/urban residence during the 2011–12 through 2018–19 influenza seasons was examined using National Immunization Survey-Flu data. The Council of American Survey Research Organizations response rates for National Immunization Survey-Flu ranged from 48% to 65% (2011–12 through the 2017–18 seasons) for the landline sample and 20%–39% (2011–12 through the 2018–19 seasons) for the cellular telephone sample. Children residing in rural areas had influenza vaccination coverage that ranged from 7.9 (2012–13 season) to 12.6 (2016–17 season) percentage points lower than children residing in urban areas, and ranged from 4.5 (2012–13 season) to 7.4 (2016–17 season) percentage points lower than children residing in suburban areas. The differences in influenza vaccination coverage among rural, suburban, and urban children were consistent over the eight seasons studied. Lower influenza vaccination coverage was observed among rural children regardless of child’s age, mother’s education, household income, or number of children under 18 years of age in the household. Rural versus urban and suburban differences in influenza vaccination coverage remained statistically significant while adjusting for selected sociodemographic characteristics. A better understanding of the reasons for lower childhood influenza vaccination coverage for children in rural and suburban areas is needed.     

Influenza vaccination uptake and socioeconomic determinants in 11 European countries

Background

The objective of this study was to assess the predictive effects of socioeconomic factors to explain influenza vaccination coverage rates in 11 European countries.

Methods

Data from national household surveys collected over up to seven consecutive seasons between 2001/2002 and 2007/2008 were analyzed to assess the associations of socioeconomic factors with immunization against influenza.

Results

In total, data from 92,101 household contacts representative for the national non-institutionalized population aged above 14 years were analyzed. Influenza vaccination coverage rates in Europe remain suboptimal with little or no progress in the last years. The results of this study indicate that gender, household income, size of household, educational level and population size of living residence may significantly contribute to explain chances of getting immunized against influenza apart from the known risk factors age and chronic illness. The effect of these socioeconomic factors was differently expressed among the countries and could not be explained solely on basis of economic characteristics of these countries.

Conclusions

Future measures should address inequalities to achieve the WHO target by 2010 with an influenza vaccination rate of 75% in the elderly. National vaccination campaigns may need to take socioeconomic segments of the population here identified as less likely of getting the influenza vaccine into account.     

Caregiver recall in childhood vaccination surveys: Systematic review of recall quality and use in low- and middle-income settings

IntroductionHigh population coverage is key to the impact of vaccines. However, vaccine coverage estimates in low- and middle-income countries (LMICs) have repeatedly been shown to be of poor quality. LMICs often rely on ‘caregiver recall’ of vaccination, the validity and collection method of which remains uncertain. We aimed to critique the quality of caregiver recall and make recommendations for its collection and use.MethodsWe performed a systematic review for methods assessing childhood vaccination coverage in LMICs. We searched Medline using variations of the key terms: (child) AND (vaccinat¹) AND (survey OR recall OR coverage) AND (reliab¹ OR valid¹). We selected articles assessing the quality of recall in LMICs and extracted reported validity, reliability and completeness. We synthesised recommendations on collecting, analysing and presenting caregiver recall for varying resource availabilities.ResultsOf 1268 articles, 134 full texts were screened and eight were included for review. There was heterogeneity in study designs, ways of incorporating recall data and outcomes measured. Sensitivity of recall was 41–98%; specificity was 12–80%. There was a dearth of reliability measures and no consistent method for dealing with data incompleteness.ConclusionThere are quality concerns with caregiver recall and difficulty in assessing it given the lack of a ‘gold standard’ for vaccine status. To improve coverage estimates and the impact of vaccines, caregiver recall should be used. Other recommendations include: recall is included for those presenting vaccine records; missing data is imputed; recall and record quality are assessed in a sub-sample; and sensitivity analyses are performed.     

Childhood Hib vaccination and pneumonia and influenza burden in US seniors

This analysis examines the potential for the elderly to receive indirect protection from pneumonia and influenza (P&I) from vaccination of children. Using data from the Centers for Medicare and Medicaid Services, the National Immunization Survey, and the Behavioral Risk Factor Surveillance System, mixed-effects models were used to assess associations between vaccination coverage and P&I on the state level overall and by urbanicity and income. As vaccination coverage in children increased, the state-level P&I rates in seniors decreased (β = −0.040, −0.074 to 0.006), where β represents the expected change in the logged age-associated rate of disease increase for a one-percentage point increase in vaccination coverage. Increasing vaccination coverage in the elderly was associated with an increase in P&I rates (β = 0.045, 0.011–0.077) in seniors. The degree of association was more prominent in urban and high income areas. The consistent associations between influenza in the elderly and vaccination coverage in children suggest that routine vaccination of children may impart some indirect protection to the elderly.     

An empirical research for demand of influenza vaccination

PURPOSE: This article examines the demand for influenza vaccination in Japan. METHODS: Original date were obtained from a survey conducted by the authors. Two approaches, usual demand analysis and conjoint analysis, were employed. The second approach, conjoint analysis, uses people's statements on how they would respond to different hypothetical situations. In this research, we ask people whether they wish to be vaccinated given different circumstances such as costs of vaccination, degree of convenience, and outbreak news. RESULTS: In the demand analysis, the vaccination rate during the 1999-2000 season was found to have increased by 0.8 percentage points compared to that of the previous season. The rate increased by 1.0 to 3.5 percentage points among the group of people who experienced influenza in the previous season. The vaccination rate also increased by 31-47 percentage points for those who were vaccinated in the previous season. A 10 percentage increase in household income decreased the demand for vaccination by 2 percentage points. Although household income was significant in only with the largest sample, this result may indicate that the time or opportunity cost for vaccination decreases the vaccination demand. In the conjoint analysis, the financial cost was significantly negative. When the cost was reduced from the current level of 6,000 yen to free of charge, the vaccination rate would increase by 43.5 percentage points. Were vaccination available at night or during holidays,! or at school or work, the rate would increase by 11 percentage points, or 16 percentage points, respectively. Most of all, news of influenza prevalence was very influential in increasing the desire for vaccination by 33 percentage points. Vaccination experience and last year's influenza experience were both significantly positive, increasing the rate by 22 and 8 percentage points, respectively. CONCLUSIONS: In the demand analysis, influenza experience and history of vaccination during the 1999-2000 season were found to be influential regarding the decision for vaccination. From the conjoint analysis, providing vaccination of night or during holidays, as well as at work or at schools would increase the demand. News of influenza outbreaks were also found to increase the vaccination demand. Higher income, however, was found to have a negative influence, suggesting that opportunity costs may be an important factor for some individuals. Habit formation effects through a history of vaccination plays quite an important role in vaccination demand.     

Validity of self-reported pneumococcal vaccination status in the elderly in Spain

The objective of this study was to evaluate the validity of information reported by the elderly on 23-valent pneumococcal polysaccharide vaccine (23vPPV) vaccination status. A cross-sectional, observational study was carried out in patients aged ≥65 years admitted to five Spanish hospitals. Data on 23vPPV vaccination history were obtained through interview of the patient or close relative and review of written medical information. The validity of the patient self-report was compared to the written medical information by calculation of the sensitivity, specificity, concordance, positive predictive value (PPV) and negative predictive value (NPV). A total of 2484 patients were initially included of whom 1814 patients (73%) responded about their vaccination status. The global sensitivity of the patient self-report was 0.74 and the specificity 0.95. The PPV was 0.92, the NPV 0.84 and the concordance 87. Vaccination cards and centralized vaccination registries in primary health care centres and hospitals should be potentiated in order to ensure that neither more nor less vaccinations are administered than are necessary.     

Validity of self-reported influenza and pneumococcal vaccination status among a cohort of hospitalized elderly inpatients

Use of self-reported vaccination status is commonplace in assessing vaccination coverage for public health programs and individuals, yet limited validity data exist. We compared self-report with provider records for pneumococcal (23vPPV) and influenza vaccine for 4887 subjects aged>or=65 years from two Australian hospitals. Self-reported influenza vaccination status had high sensitivity (98%), positive predictive value (PPV) (88%) and negative predictive value (NPV) (91%), but low specificity (56%). Self-reported 23vPPV (previous 5 years) had a sensitivity of 84%, specificity 77%, PPV 85% and NPV 76%. Clinicians can be reasonably confident of self-reported influenza vaccine status, and for positive self-report for 23vPPV in this setting. For program evaluation, self-reported influenza vaccination coverage among inpatients overestimates true coverage by about 10% versus 1% for 23vPPV. Self-report remains imperfect and whole-of-life immunisation registers a preferable goal.     

COVID-19 and missed or delayed vaccination in 26 middle- and high-income countries: An observational survey

BackgroundThe COVID-19 pandemic has disrupted vaccination services and raised the risk of a global resurgence of preventable diseases. We assessed the extent of and reasons for missed or delayed vaccinations (hereafter ‘missed’) in middle- and high-income countries in the early months of the pandemic.MethodsFrom May to June 2020, participants completed an online survey on missed vaccination. Analyses separated missed childhood and adult vaccination in middle-and high-income countries.ResultsRespondents were 28,429 adults from 26 middle- and high-income countries. Overall, 9% of households had missed a vaccine, and 13% were unsure. More households in middle- than high-income countries reported missed childhood vaccination (7.6% vs. 3.0%) and missed adult vaccination (9.6% vs. 3.4%, both p < .05). Correlates of missed childhood vaccination in middle-income countries included COVID-19 risk factors (respiratory and cardiovascular diseases), younger age, male sex, employment, psychological distress, larger household size, and more children. In high-income countries, correlates of missed childhood vaccination also included immunosuppressive conditions, but did not include sex or household size. Fewer correlates were associated with missed adult vaccination other than COVID-19 risk factors and psychological distress. Common reasons for missed vaccinations were worry about getting COVID-19 at the vaccination clinic (15%) or when leaving the house (11%). Other reasons included no healthcare provider recommendation, clinic closure, and wanting to save services for others.InterpretationMissed vaccination was common and more prevalent in middle- than high-income countries. Missed vaccination could be mitigated by emphasizing COVID-19 safety measures in vaccination clinics, ensuring free and accessible immunization, and clear healthcare provider recommendations.     

Evaluation of potentially achievable vaccination coverage with simultaneous administration of vaccines among children in the United States

BackgroundRoutine administration of all age-appropriate doses of vaccines during the same visit is recommended for children by the National Vaccine Advisory Committee (NVAC) and the Advisory Committee on Immunization Practices (ACIP).MethodsEvaluate the potentially achievable vaccination coverage for ≥4 doses of diphtheria and tetanus toxoids and acellular pertussis vaccine (4+DTaP), ≥4 doses of pneumococcal conjugate vaccine (4+PCV), and the full series of Haemophilus influenzae type b vaccine (Hib-FS) with simultaneous administration of all recommended childhood vaccines. Compare the potentially achievable vaccination coverage to the reported vaccination coverage for calendar years 2001 through 2013; by state in the United States and by selected socio-demographic factors in 2013. The potentially achievable vaccination coverage was defined as the coverage possible for the recommended 4+DTaP, 4+PCV, and Hib-FS if missed opportunities for simultaneous administration of all age-appropriate doses of vaccines for children had been eliminated.ResultsCompared to the reported vaccination coverage, the potentially achievable vaccination coverage for 4+DTaP, 4+PCV, and Hib-FS could have increased significantly (P < 0.001), the vaccination coverage would have achieved the 90% target of Healthy People 2020 for the three vaccines beginning in 2005, 2008, and 2011 respectively. In 2013, the potentially achievable vaccination coverage increased significantly across all selected socio-demographic factors, potentially achievable vaccination coverage would have reached the 90% target for more than 51% of the states in the United States.ConclusionsThe findings in this study suggest that fully utilization of all opportunities for simultaneous administration of all age-eligible childhood doses of vaccines during the same vaccination visit is a critical strategy for achieving the vaccination coverage target of Healthy People 2020. Encouraging providers to deliver all recommended vaccines that are due at each visit by implementing client reminder and recall systems might decrease missed opportunities for simultaneous administration of childhood vaccines.     

Timely completion of childhood vaccination and its predictors in Burkina Faso

BackgroundDespite important progress in global vaccination coverage, many countries are still facing preventable disease outbreaks. Timely vaccination is important in getting adequate protection against disease. In light of the paucity of relevant literature, this study investigated the timely completion of childhood routine immunization and identified factors associated with timely vaccination in Burkina Faso.MethodsWe extracted data on child vaccination and other child characteristics from a household survey conducted across 24 districts in 2017. We extracted data on health system characteristics from a parallel facility survey. We applied a Kaplan-Meier time-to-event analysis to estimate timely vaccination coverage defined as the proportion of children that received a given vaccine in the period between three days before and 28 days after the recommended age. We used a Cox proportional hazard model with mixed effects to identify factors associated with timely vaccination.ResultsIn total, 3,138 children aged between 16 and 36 months who could present an immunization booklet were included in the study.The main finding is the existence of an important gap showing that timely vaccination coverage was lower than vaccination coverage. More specifically,this gap ranged from 16% for BCG to 43% for Penta 3. In addition, region and distance between the household and the nearest health facility were the main factors associated with timely full vaccination coverage and specifically for Penta3, MCV1 and MCV2.ConclusionsThis study highlights that timely vaccination coverage remains substantially lower than vaccination coverage. Timeliness of vaccination should therefore be considered as a metric to assess the status of immunization in a country. Geographical accessibility continues to represent a major barrier to timely vaccination, calling for specific interventions on both supply-side (e.g. outreach activities) and demand-side (e.g. vouchers or community-based interventions for vaccination) to counteract its negative effect.     

Late vaccination reinforcement during a measles epidemic in Niamey, Niger (2003-2004)

Low measles vaccination coverage (VC) leads to recurrent epidemics in many African countries. We describe VC before and after late reinforcement of vaccination activities during a measles epidemic in Niamey, Niger (2003-2004) assessed by Lot Quality Assurance Sampling (LQAS). Neighborhoods of Niamey were grouped into 46 lots based on geographic proximity and population homogeneity. Before reinforcement activities, 96% of lots had a VC below 70%. After reinforcement, this proportion fell to 78%. During the intervention 50% of children who had no previous record of measles vaccination received their first dose (vaccination card or parental recall). Our results highlight the benefits and limitations of vaccine reinforcement activities performed late in the epidemic.     

Exploring socio-demographic and geospatial variation in human papillomavirus vaccination uptake in Virginia

Significant variation in human papillomavirus (HPV) vaccine coverage exists across the United States. A closer look at state and region-specific coverage is necessary to identify potentially modifiable disparities. Using ArcGIS software, we identify geospatial variation in HPV vaccine coverage in the state of Virginia and examine the relationship between various socio-demographic indicators and HPV vaccination uptake. HPV vaccination rates among adolescents 11 to 17 years as of 07/01/2018 were retrieved at the zip-code level from the Virginia Immunization Information System and chloropleth maps produced. The ArcGIS Hot Spot Analysis tool identified spatial clusters of zip codes with high and low vaccination rates. Population characteristics and socioeconomic indicators were retrieved from the 2010 United States Census and compared between statistically significant clusters of higher or lower than expected vaccination rates. Regions with significantly lower initiation rates were less populated, less educated, and had a lower median household income (MHI) with higher rates of poverty and unemployment. Among male adolescents, these areas had a significantly lower density of primary care providers and smaller African American and Hispanic populations. In contrast, regions with significantly lower series completion were more populated and had a higher MHI, but there was no difference in provider density or minority population. Ultimately, regional socioeconomic indicators are significant predictors of HPV vaccination, but have contrasting implications for series initiation and completion. Targeted interventions and safety net programs have traditionally focused on the socioeconomically disadvantaged, however it is the more affluent communities that may be struggling with series completion.