Immunization Information Systems Data Research Articles

Safety of Ancestral Monovalent BNT162b2, mRNA-1273, and NVX-CoV2373 COVID-19 Vaccines in US Children Aged 6 Months to 17 Years

Active monitoring of health outcomes after COVID-19 vaccination provides early detection of rare outcomes that may not be identified in prelicensure trials. To conduct near-real-time monitoring of health outcomes after COVID-19 vaccination in the US pediatric population. This cohort study evaluated 21 prespecified health outcomes after exposure before early 2023 to BNT162b2, mRNA-1273, or NVX-CoV2373 ancestral monovalent COVID-19 vaccines in children aged 6 months to 17 years by applying a near-real-time monitoring framework using health care data from 3 commercial claims databases in the US (Optum [through April 2023], Carelon Research [through March 2023], and CVS Health [through February 2023]). Increased rates of each outcome after vaccination were compared with annual historical rates from January 1 to December 31, 2019, and January 1 to December 31, 2020, as well as between April 1 and December 31, 2020. Receipt of an ancestral monovalent BNT162b2, mRNA-1273, or NVX-CoV2373 COVID-19 vaccine dose identified through administrative claims data linked with Immunization Information Systems data. Twenty-one prespecified health outcomes, of which 15 underwent sequential testing and 6 were only monitored descriptively due to lack of historical rates. Among 4 102 016 vaccinated enrollees aged 6 months to 17 years, 2 058 142 (50.2%) were male and 3 901 370 (95.1%) lived in an urban area. Thirteen of 15 sequentially tested outcomes did not meet the threshold for a statistical signal. Statistical signals were detected for myocarditis or pericarditis after BNT162b2 vaccination in children aged 12 to 17 years and seizure after vaccination with BNT162b2 and mRNA-1273 in children aged 2 to 4 or 5 years. However, in post hoc sensitivity analyses, a statistical signal for seizure was observed only after mRNA-1273 when 2019 background rates were selected; no statistical signal was observed when 2022 rates were selected. In this cohort study of pediatric enrollees across 3 commercial health insurance databases, statistical signals detected for myocarditis or pericarditis after BNT162b2 (ages 12-17 years) were consistent with previous reports, and seizures after BNT162b2 (ages 2-4 years) and mRNA-1273 vaccinations (ages 2-5 years) should be further investigated in a robust epidemiologic study with confounding adjustment. The US Food and Drug Administration concludes that the known and potential benefits of COVID-19 vaccination outweigh the known and potential risks of COVID-19 infection.

Federal Retail Pharmacy Program Contributions to Bivalent mRNA COVID-19 Vaccinations Across Sociodemographic Characteristics - United States, September 1, 2022-September 30, 2023.

The Federal Retail Pharmacy Program (FRPP) facilitated integration of pharmacies as partners in national efforts to scale up vaccination capacity during the COVID-19 pandemic emergency response. To evaluate FRPP's contribution to vaccination efforts across various sociodemographic groups, data on COVID-19 bivalent mRNA vaccine doses administered during September 1, 2022-September 30, 2023, were evaluated from two sources: 1) FRPP data reported directly to CDC and 2) jurisdictional immunization information systems data reported to CDC from all 50 states, the District of Columbia, U.S. territories, and freely associated states. Among 59.8 million COVID-19 bivalent vaccine doses administered in the United States during this period, 40.5 million (67.7%) were administered by FRPP partners. The proportion of COVID-19 bivalent doses administered by FRPP partners ranged from 5.9% among children aged 6 months-4 years to 70.6% among adults aged 18-49 years. Among some racial and ethnic minority groups (e.g., Hispanic or Latino, non-Hispanic Black or African American, non-Hispanic Native Hawaiian or other Pacific Islander, and non-Hispanic Asian persons), ≥45% of COVID-19 bivalent vaccine doses were administered by FRPP partners. Further, in urban and rural areas, FRPP partners administered 81.6% and 60.0% of bivalent vaccine doses, respectively. The FRPP partnership administered approximately two thirds of all bivalent COVID-19 vaccine doses in the United States and provided vaccine access for persons across a wide range of sociodemographic groups, demonstrating that this program could serve as a model to address vaccination services needs for routine vaccines and to provide health services in other public health emergencies.

Pivoting COVID-19 Resources for an Equitable Mpox Vaccine Response in Louisiana

IntroductionThe first case of mpox in Louisiana was identified two months ahead of Southern Decadence Festival in New Orleans, the largest LGBTQ+ Pride festival in the South. With mpox case numbers reflecting racial disparities, the objective was to mount an equitable vaccination response. MethodsThe Louisiana Department of Health (LDH) rapidly pivoted its Covid-19 resources and strategies – specifically, using vaccine strike teams and mobile events, in-state vaccine redistribution through centralized warehousing and shipping support, and community partnerships – to now control mpox transmission. Here we have evaluated State-based Immunization Information System data to examine whether the vaccination response was geographically and racially equitable. Geographic equity was measured by taking into account vaccine availability as well as uptake in areas with high Social Vulnerability Index (SVI). Results113 providers were enrolled in the vaccination program, and 96 mobile vaccination events were held in locations frequented by at-risk populations. Racial disparities among vaccine recipients decreased over time, and vaccine availability and uptake was equitable in high SVI areas. However, Black, female and Hispanic/Latinx patients had significantly higher risk of not completing the two-dose series relative to their counterparts. ConclusionThe mpox vaccination response in Louisiana was geographically equitable, though some disparities remained.

496. Maternal Participation in Enrollment Interview and Risk of Bias in a Multicenter Pediatric Network Evaluating COVID-19 Vaccine Effectiveness in Infants

Abstract Background The Overcoming COVID-19 network uses a case-control design to estimate effectiveness of maternal COVID-19 vaccination on COVID-19 associated hospitalization of infants. Vaccination history is asked in a maternal interview and verified with jurisdictional immunization information systems (IIS). In the absence of an interview, IIS data alone are used. These data may become less complete as the public health emergency ends and COVID-19 vaccines move to the commercial market. Vaccination status may rely more on interviews, potentially biasing VE estimates. We analyzed possible future participation bias. Methods Maternal interview participation was assessed for 699 case infants < 6 months hospitalized with COVID-19 and 613 SARS-CoV-2 test-negative control infants < 6 months with COVID-like illness admitted to 29 U.S. hospitals from December 19, 2021–January 31, 2023. To assess recent changes in participation, two Omicron subvariant periods were defined: Period 1 (December 19, 2021–July 18, 2022) and Period 2 (July 19, 2022–January 31, 2023). Interview participation percentages for vaccinated and unvaccinated cases and controls, overall and by subvariant, were used to calculate interview participation bias factors (BF) (Table 1). The BF can be used to adjust observed estimates of VE for potential participation bias. Results Overall, vaccination was more frequent among participating case (25%) vs. non-participating case (16%) mothers (Table 2). Vaccination status did not differ by interview participation among controls. Participation was highest in Period 1 (68% in vaccinated cases) and lowest in Period 2 (31% in vaccinated controls) (Table 3). During Period 1, the BF was 1.0, suggesting no participation bias would occur by limiting to interviewed participants. During Period 2, the BF was 1.9. Independent of other possible biases, differences in participation by case/control and vaccination status would be biased by a factor of 1.9, lowering the observed VE. Conclusion Participation in the interview differed by case/control and vaccination status during recent Omicron subvariant circulation. Independent of other biases, our results suggest that future estimates of maternal VE could be biased if future estimates of maternal VE include only women who complete an interview. Disclosures Regina Simeone, PhD, Pfizer: Stocks/Bonds Natasha B. Halasa, MD, MPH, Merck: Grant/Research Support|Quidell: Grant/Research Support|Quidell: donation of kits|Sanofi: Grant/Research Support|Sanofi: vaccine support

Identification of Spatial Clusters of Undervaccination Patterns Among Children Aged

Spatial clustering of undervaccination leads to increased risk of vaccine-preventable diseases. We identified spatial clustering of undervaccination patterns among children aged <24 months in Montana. We used Montana's immunization information system data to analyze deidentified vaccination records of children aged <24 months born from January 2015 through November 2017. We measured 3 outcomes that were not mutually exclusive: not completing the combined 7-vaccine series by age 24 months, having an undervaccination pattern indicative of parental hesitancy, and having an undervaccination pattern indicative of structural barriers to timely vaccination. Using geomasked residential addresses, we conducted separate Bernoulli spatial scans with a randomization P < .01 to identify spatial clusters consisting of ≥100 children for each outcome and calculated the relative risk of having the undervaccination pattern inside versus outside the cluster. Of 31 201 children aged <24 months included in our study, 11 712 (37.5%) had not completed the combined 7-vaccine series by age 24 months, and we identified 5 spatial clusters of this outcome across Montana. We identified 4 clusters of undervaccination patterns indicative of parental vaccine hesitancy, all in western Montana. The cluster with the largest relative risk (2.3) had a radius of 23.7 kilometers (n = 762 children, P < .001). We also identified 4 clusters of undervaccination patterns indicative of structural barriers, with 3 of the largest clusters in eastern Montana. In Montana, different strategies to increase routine and timely childhood vaccination are needed in distinct areas of this large and predominantly rural state. Immunization information system data can pinpoint areas where interventions to increase vaccination uptake are needed.

Estimating Vaccine Hesitancy in Colorado by Using Immunization Information System Data.

Vaccine hesitancy is a complex issue that threatens global health. We used data from the Colorado Immunization Information System (CIIS) to quantify vaccine hesitancy. We examined immunization records from CIIS for patients age 2 up to 9 months to estimate vaccine hesitancy by tabulating the number of doses received per visit and comparing it with the number of expected doses based on recommendations of the Advisory Committee on Immunization Practices. We calculated the percentage of patients in each vaccine hesitancy group who were up to date on the 7-antigen series by age 35 months. We examined the distribution of vaccine-hesitant populations among vaccination providers who report to CIIS to estimate the difference in vaccine-hesitant patient populations among vaccination providers in Colorado. Of 201 450 patients, 5147 (2.6%) consistently limited the number of shots received at each visit as compared with recommendations from the Advisory Committee on Immunization Practices; 166 927 (82.9%) patients did not limit the number of shots received; 5693 (2.8%) limited the number of shots received at >1 visit but not all visits; and 23 683 (11.8%) limited the number of shots received at only 1 visit. We found differences in vaccine hesitancy distributions among certain Colorado vaccination providers. Immunization information system data, although sometimes incomplete, offer an opportunity to investigate state-level vaccine hesitancy. Areas of future research include performing similar analyses over time and determining geographic and socioeconomic factors that contribute to vaccine hesitancy.

COVID-19-Associated Hospitalizations Among Vaccinated and Unvaccinated Adults 18 Years or Older in 13 US States, January 2021 to April 2022

Understanding risk factors for hospitalization in vaccinated persons and the association of COVID-19 vaccines with hospitalization rates is critical for public health efforts to control COVID-19. To determine characteristics of COVID-19-associated hospitalizations among vaccinated persons and comparative hospitalization rates in unvaccinated and vaccinated persons. From January 1, 2021, to April 30, 2022, patients 18 years or older with laboratory-confirmed SARS-CoV-2 infection were identified from more than 250 hospitals in the population-based COVID-19-Associated Hospitalization Surveillance Network. State immunization information system data were linked to cases, and the vaccination coverage data of the defined catchment population were used to compare hospitalization rates in unvaccinated and vaccinated individuals. Vaccinated and unvaccinated patient characteristics were compared in a representative sample with detailed medical record review; unweighted case counts and weighted percentages were calculated. Laboratory-confirmed COVID-19-associated hospitalization, defined as a positive SARS-CoV-2 test result within 14 days before or during hospitalization. COVID-19-associated hospitalization rates among vaccinated vs unvaccinated persons and factors associated with COVID-19-associated hospitalization in vaccinated persons were assessed. Using representative data from 192 509 hospitalizations (see Table 1 for demographic information), monthly COVID-19-associated hospitalization rates ranged from 3.5 times to 17.7 times higher in unvaccinated persons than vaccinated persons regardless of booster dose status. From January to April 2022, when the Omicron variant was predominant, hospitalization rates were 10.5 times higher in unvaccinated persons and 2.5 times higher in vaccinated persons with no booster dose, respectively, compared with those who had received a booster dose. Among sampled cases, vaccinated hospitalized patients with COVID-19 were older than those who were unvaccinated (median [IQR] age, 70 [58-80] years vs 58 [46-70] years, respectively; P < .001) and more likely to have 3 or more underlying medical conditions (1926 [77.8%] vs 4124 [51.6%], respectively; P < .001). In this cross-sectional study of US adults hospitalized with COVID-19, unvaccinated adults were more likely to be hospitalized compared with vaccinated adults; hospitalization rates were lowest in those who had received a booster dose. Hospitalized vaccinated persons were older and more likely to have 3 or more underlying medical conditions and be long-term care facility residents compared with hospitalized unvaccinated persons. The study results suggest that clinicians and public health practitioners should continue to promote vaccination with all recommended doses for eligible persons.

Evaluating vaccination coverage and timeliness in American Indian/Alaska Native and non-Hispanic White children using state immunization information system data, 2015-2017

Comprehensive estimates of vaccination coverage and timeliness of vaccine receipt among American Indian/Alaska Native (AI/AN) children in the United States are lacking. This study’s objectives were to quantify vaccination coverage and timeliness, as well as the proportion of children with specific undervaccination patterns, among AI/AN and non-Hispanic White (NHW) children ages 0–24 months in Montana, a large and primarily rural U.S. state. Data from Montana’s immunization information system (IIS) for children born 2015–2017 were used to calculate days undervaccinated for all doses of seven recommended vaccine series. After stratifying by race/ethnicity, up-to-date coverage at key milestone ages and the proportion of children demonstrating specific patterns of undervaccination were reported. Among n = 3,630 AI/AN children, only 23.1% received all recommended vaccine doses on-time (i.e., zero days undervaccinated), compared to 40.4% of n = 18,022 NHW children (chi-square p < 0.001). A greater proportion of AI/AN children were delayed at each milestone age, resulting in lower overall combined 7-vaccine series completion, by age 24 months (AI/AN: 56.6%, NHW: 64.3%, chi-square p < 0.001). As compared with NHW children, a higher proportion of AI/AN children had undervaccination patterns suggestive of structural barriers to accessing immunization services and delayed starts to vaccination. More than three out of four AI/AN children experienced delays in vaccination or were missing doses needed to complete recommended vaccine series. Interventions to ensure on-time initiation of vaccine series at age 2 months, as well initiatives to encourage completion of multi-dose vaccine series, are needed to reduce immunization disparities and increase vaccination coverage among AI/AN children in Montana.

Evidenced-Based Approaches States and Territories Can Implement to Advance Adult Immunization Uptake During the COVID-19 Pandemic and Beyond.

Evidenced-Based Approaches States and Territories Can Implement to Advance Adult Immunization Uptake During the COVID-19 Pandemic and Beyond.

Association of Diphtheria-Tetanus–Acellular Pertussis Vaccine Timeliness and Number of Doses With Age-Specific Pertussis Risk in Infants and Young Children

In most countries, the diphtheria-tetanus-acellular pertussis (DTaP) vaccine is administered as a 3-dose infant series followed by additional booster doses in the first 5 years of life. Short-term immunity from the DTaP vaccine can depend on the number, timing, and interval between doses. Not receiving doses in a timely manner might be associated with a higher pertussis risk. To examine the association between number and timeliness of vaccine doses and age-specific pertussis risk. This population-based, retrospective cohort study used Washington State Immunization Information System data and pertussis surveillance data from Public Health Seattle and King County, Washington. Included participants were children aged 3 months to 9 years born or living in King County, Washington, between January 1, 2008, and December 31, 2017. Data were analyzed from June 30 to December 1, 2019. Being undervaccinated (receiving fewer than recommended doses at a given age) or delayed vaccination (not receiving doses within time frames recommended by Centers for Disease Control and Prevention). Suspected, probable, and confirmed pertussis diagnosis. A total of 316 404 children (median age, 65.2 months [interquartile range, 35.3-94.1 months]; 162 025 boys [51.2%]) as of December 31, 2017, with 17.4 million person-months of follow-up were included in the analysis. A total of 19 943 children (6.3%) had no vaccines recorded in the Immunization Information System, 116 193 (36.7%) received a vaccine with a delay, and 180 268 (56.9%) were fully vaccinated with no delay. Delayed vaccination and undervaccination rates were higher for older children (17.6% delayed or undervaccinated at age 2 months for dose 1 at 3 months vs 41.6% at age 5 years for dose 5) but improved for successive birth cohorts (52.2% for 2008 birth cohort vs 32.3% for 2017 birth cohort). Undervaccination was significantly associated with higher risk of pertussis for the 3-dose primary series (adjusted relative risk [aRR], 4.8; 95% CI, 3.1-7.6), the first booster (aRR, 3.2; 95% CI, 2.3-4.5), and the second booster (aRR, 4.6; 95% CI, 2.6-8.2). However, delay in vaccination among children who received the recommended number of vaccine doses was not associated with pertussis risk. The results of this cohort study suggest that undervaccination is associated with higher pertussis risk. Short delays in vaccine receipt may be less important if the age-appropriate number of doses is administered, but delaying doses is not recommended. Ensuring that children receive all doses of pertussis vaccine, even if there is some delay, is important.

Provider group type and Tdap coverage in pregnancy

IntroductionThe Advisory Committee on Immunization Practices (ACIP) has focused on maternal Tdap immunization as an important means to protect neonates from pertussis infections. There is little published data on provider and/or clinic characteristics as predictors of maternal Tdap uptake. This study examined differences in maternal Tdap coverage in women delivering at a single academic institution, but cared for prenatally in different clinical settings, in 2013, 2014, and 2015. Additionally, the accuracy and utilization of Vermont's immunization information system (IIS) was assessed. MethodsThis was a retrospective, multiple time-point cross-sectional analysis of annual maternal Tdap coverage in women delivering at a single academic institution in the 3 years following a fundamental change in national maternal Tdap vaccination guidelines. Tdap administration was examined across different obstetric groups using chart review and data from the state's IIS. ResultsAll obstetric care groups except the resident-staffed clinic significantly increased maternal Tdap coverage in 2014, compared to 2013 coverage, with no further increase in 2015. In contrast, there was no increase in maternal Tdap coverage in 2014 in the resident-staffed clinics, but then a statistically significant increase in 2015. Overall Tdap coverage in 2014 was 80.4%, with variation in Tdap coverage between clinics types. In the subset of women who were cared for by the University-based groups, there was significant variation in Tdap coverage between clinics, despite racial homogeneity, which persisted after adjustment for maternal age and insurance type. The state's IIS was found to be highly accurate, using individual chart review as the “gold standard.” DiscussionWhile we demonstrated high maternal Tdap coverage in women delivering at our institution, differences in clinic type and provider training appeared to impact immunization rates, as well as how quickly evolving national recommendations were adopted. Additionally, the fidelity of the state's IIS data was verified.

A population‐based reminder intervention to improve human papillomavirus vaccination rates among adolescents at routine vaccination age

ObjectivesPublic health authorities have the resources to conduct efficient immunization reminder interventions to improve vaccine uptake. The objective of this initiative was to design and implement a cost-effective centralized HPV vaccine reminder using New York State Immunization Information System data as one of five prespecified activities to increase initiation and completion among 11- to 13-year-old adolescents. MethodsThe New York State Department of Health sent reminder letters to the parents or guardians of eligible adolescents who were due for the first dose of HPV vaccine and observed HPV vaccine administration in the six months after each mailing. Subjects were randomized into an intervention group, mailed on May 14, 2015 and a control group, mailed on December 8, 2015. ResultsThe analysis consisted of 81,558 eligible letter recipients. Letter recipients were 2 percent more likely to initiate vaccination than control subjects. Significant increases in vaccine uptake were observed for all age and gender strata. The intervention cost was $30.95 for each adolescent who initiated the HPV vaccine series. New York State Department of Health received far less public feedback, including negative feedback, about this intervention that was originally anticipated. ConclusionsPublic health entities can effectively utilize existing resources to conduct large-scale reminder interventions targeting a jurisdiction’s entire 11- to 13-year-old population.

Statewide analysis of missed opportunities for human papillomavirus vaccination using vaccine registry data

BackgroundHuman papillomavirus (HPV) vaccine 3-dose completion rates among adolescent females in the US are low. Missed opportunities impede HPV vaccination coverage. MethodsA population-based secondary data analysis of de-identified vaccination and demographic data from the Utah Statewide Immunization Information System (USIIS) was conducted. Records were included from 25,866 females ages 11–26 years at any time during 2008–2012 who received at least one of the following adolescent vaccinations documented in the USIIS: Tdap (Tetanus, Diphtheria, Pertussis), meningococcal, and/or influenza. A missed opportunity for HPV vaccination was defined as a clinical encounter where the patient received at least one adolescent vaccination, but not a HPV vaccine. ResultsOf 47,665 eligible visits, there were 20,911 missed opportunities (43.87%). Age group, race/ethnicity, and rurality were significantly associated with missed opportunity (p<0.0001). In a multivariable mixed-effects logistic regression model that included ethnicity, location and age, as fixed effects and subject as a random effect, Hispanics were less likely to have a missed opportunity than whites OR 0.59 (95% CI: 0.52–0.66), small rural more likely to have a missed opportunity than urban youth OR 1.8 (95% CI: 1.5–2.2), and preteens more likely than teens OR 2.4 (95% CI: 2.2–2.7). ConclusionMissed clinical opportunities are a significant barrier to HPV vaccination among female adolescents. Interventions targeted at providers who serve patient groups with the highest missed opportunities are needed to achieve adequate protection from HPV-associated illnesses. ImpactThis is one of the first studies to utilize state immunization information system data to assess missed opportunities for HPV vaccination.

Human Papillomavirus Vaccination in Washington State: Estimated Coverage and Missed Opportunities, 2006-2013.

Human papillomavirus (HPV) causes almost all cervical cancer in women and contributes to vaginal, anal, oropharyngeal, and penile cancer morbidity and mortality. Although vaccines effective in preventing up to nine types of HPV are available, vaccination rates are low nationally. We assessed HPV vaccination coverage by age, sex, and county using Washington State Immunization Information System data. We calculated on-time dose coverage by county and statewide among adolescents aged 11-12 years and assessed coverage by age 18 years. We calculated missed opportunities as the number of visits at which doses of other adolescent vaccines were administered without administration of the first dose of HPV vaccine (HPV1). In 2013, HPV vaccination coverage estimates with one, two, and three doses (HPV1-3) for adolescents aged 11-12 years were 48.5%, 32.4%, and 18.3% among girls and 31.2%, 17.1%, and 8.1% among boys. The three-dose HPV vaccine coverage estimate increased to 40.1% among girls by age 18 but was unchanged for boys. Coverage estimates varied by age, sex, and county. One-third of eligible unvaccinated girls and two of five eligible boys aged 11-17 years had at least one missed opportunity to receive HPV1. Despite a recommendation to vaccinate adolescents aged 11-12 years, HPV vaccination is often delayed and coverage levels among all age groups are below national target levels. Improved understanding of the variability of HPV vaccination coverage rates by age, sex, and county can inform targeted interventions statewide.

A National Survey of Immunization Programs Regarding Immunization Information Systems Data Sharing and Use

To determine and characterize practices regarding data sharing and usage (particularly for research) in immunization information systems (IISs), as well as barriers to using such data for research. We surveyed immunization program managers (IPMs) associated with all 64 Centers for Disease Control and Prevention grantee immunization programs (IPs) between July and September 2012. More than 95% of IPMs (61/64) responded. The top 2 barriers reported by IPMs to using IIS data for research were insufficient time and too few employees, irrespective of whether or not the jurisdiction reported using data for research purposes. Those IPMs who agreed with the statement "Research is part of the mission of an immunization program" were more likely to report using data for research (P = .045). Among those who responded, the most common kind of IIS research conducted involved determinants of vaccination coverage (n = 24/26; 92%). A greater percentage of IPMs in jurisdictions that reported using IIS data for research reported having data-sharing agreements in place. Those IPs that have used IIS data for research were more likely to report online IIS provider enrollment, integration with insurance company records, and integration with hospital records. Alternatively, IPs that did not report using IIS data for research were more likely to have IISs with modules addressing topics such as adverse event reporting, smallpox, and first-responder vaccination. Staff size and time were the 2 most cited barriers to conducting research with IIS data. Therefore, focus should also be placed on providing IPs with the resources needed to conduct such research.

Vaccinating My Way—Use of Alternative Vaccination Schedules in New York State

To identify children vaccinated following an alternative vaccine schedule using immunization information system data and determine the impact of alternative schedule use on vaccine coverage. Children born in New York State, outside New York City, between January 1, 2009 and August 14, 2011 were assessed for vaccination patterns consistent with use of an alternative schedule. Children who by 9 months of age had at least 3 vaccination visits recorded in the statewide mandatory immunization information system after 41 days of age were classified as either attempting to conform to the Centers for Disease Control and Prevention published recommended vaccination schedule or an alternative schedule. The number of vaccination visits and up-to-date status at age 9 months were compared between groups. Of the 222 628 children studied, the proportion of children following an alternative schedule was 25%. These children were significantly less likely to be up-to-date at age 9 months (15%) compared with those conforming to the routine schedule (90%, P < .05). Children following an alternative schedule on average had about 2 extra vaccine visits compared with children following a routine schedule (P < .05). Almost 1 in 4 children in this study appear to be intentionally deviating from the routine schedule. Intentional deviation leads to poor vaccination coverage leaving children vulnerable to infection and increasing the potential for vaccine-preventable disease outbreaks.

Immunization Information Systems: Successes and challenges

As the number and type of vaccinations offered by pharmacists increase, improving pharmacies' use of Immunization Information Systems (IIS) is important to ensuring accurate data exchange among providers. In an effort to understand the nature of pharmacy reporting to IIS, the American Immunization Registry Association (AIRA) conducted a survey to determine current pharmacy reporting practices to IIS and successes and challenges of pharmacy–IIS data exchange. The following is a snapshot of the survey results.

The role of ethnicity and travel on Hepatitis A vaccination coverage and disease incidence in Arizona at the United States–Mexico Border

Background: Hepatitis A (HAV) incidence has decreased in the United States, yet regional disparities persist. The role of international travel has become increasingly important in HAV transmission. We compared the relative burden of HAV in border and non-border regions in Arizona and examined the role of travel in sustaining HAV transmission.Methods: HAV vaccination coverage was calculated by age and region, using Arizona State Immunization Information System data. Incidence, demographics, and risk factors of cases reported through Arizona’s infectious disease surveillance system between 2006 and 2011 were analyzed.Results: Hepatitis A incidence was higher in the border region of Arizona. Compared with the rest of Arizona, one-dose coverage in children <15 years was lower in the border region until 2008. Second dose coverage was lower in the border region, particularly among Spanish speakers. International travel among cases was generally high; however, in the border region cases were more likely to visit Mexico or South/Central America (94% vs. 80%, P value = 0.01) and be Hispanic (68% vs. 42%, P value = 0.0003).Conclusions: Rates of HAV continue to be higher in the Arizona border region; the risk appears particularly high among Hispanics with recent travel in the Americas. Border surveillance should be emphasized, along with vaccination of all travelers, to continue to decrease and control HAV.

A Systematic Evaluation of Different Methods for Calculating Adolescent Vaccination Levels Using Immunization Information System Data

Immunization information systems (IISs) are valuable surveillance tools; however, population relocation may introduce bias when determining immunization coverage. We explored alternative methods for estimating the vaccine-eligible population when calculating adolescent immunization levels using a statewide IIS. We performed a retrospective analysis of the Michigan State Care Improvement Registry (MCIR) for all adolescents aged 11-18 years registered in the MCIR as of October 2010. We explored four methods for determining denominators: (1) including all adolescents with MCIR records, (2) excluding adolescents with out-of-state residence, (3) further excluding those without MCIR activity ≥ 10 years prior to the evaluation date, and (4) using a denominator based on U.S. Census data. We estimated state- and county-specific coverage levels for four adolescent vaccines. We found a 20% difference in estimated vaccination coverage between the most inclusive and restrictive denominator populations. Although there was some variability among the four methods in vaccination at the state level (2%-11%), greater variation occurred at the county level (up to 21%). This variation was substantial enough to potentially impact public health assessments of immunization programs. Generally, vaccines with higher coverage levels had greater absolute variation, as did counties with smaller populations. At the county level, using the four denominator calculation methods resulted in substantial differences in estimated adolescent immunization rates that were less apparent when aggregated at the state level. Further research is needed to ascertain the most appropriate method for estimating vaccine coverage levels using IIS data.

2009 H1N1 and Seasonal Influenza Immunization Among Pregnant Women: A Comparison of Different Sources of Immunization Information

Validity of prenatal immunization data from different sources has not been assessed. We evaluated prenatal 2009 H1N1 and seasonal influenza (FLU) data obtained from state immunization information systems (IIS), medical record abstraction (MRA), and participant recall using medical care logs (NCS-MCL). 2009 H1N1 and FLU data were obtained from IIS and MRA for 325 pregnant women participating in the National Children's Study at three locations (SD/MN, NC, WI). Women recalled immunizations at first pregnancy visit and at 16-17 and 36 weeks' gestation (NCS-MCL). The proportion of women with vaccine information obtainable from each data source was determined, and proportions immunized as determined using different data sources were compared. IIS data were available for 82%, MRA for 97%, and NCS-MCL for 93% of women. No mention of either vaccine occurred in 29% (range 4-48%) of IIS, 40% of MRA (25-59%), and 59% (43-82%) in NCS-MCL. Best agreement between sources was 2009 H1N1 vaccine in MRA versus IIS [kappa (95% CI) of 0.44 (0.32-0.55)], with poorest agreement for FLU in IIS versus NCS-MCL [0.11 (-0.03 to 0.25)]. IIS was the most sensitive method for identifying women receiving 2009 H1N1 vaccine (92%); MRA was most sensitive for FLU vaccine (81%). IIS provided the most complete and sensitive data for 2009 H1N1 immunizations and MRA the most complete and sensitive data for FLU; IIS data were available for a smaller percent of population than MRA. NCS-MCL was the least sensitive method for identifying vaccinated women.