Simon J Hambidge

Kaiser Permanente, Oakland, California, United States

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Publications (59)258.04 Total impact

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    ABSTRACT: To describe childhood weight gain using body mass index (BMI) z-score trajectories in a low-income urban safety-net population and identify among gender- and race/ethnicity-specific groups any trends for increased risk.
    Academic pediatrics. 08/2014;
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    ABSTRACT: In response to widespread pertussis outbreaks and infant deaths, in 2010, the California Department of Health (CDPH) and in 2011 the Advisory Committee on Immunization Practices (ACIP) advised that the tetanus toxoid, reduced diphtheria toxoid and acellular pertussis (Tdap) vaccine be administered during pregnancy. Goals of this study were to describe Tdap coverage among pregnant women following these recommendations.
    Preventive medicine. 06/2014;
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    ABSTRACT: Little is known regarding the timing of childhood vaccination and postvaccination seizures.METHODS: In a cohort of 323 247 US children from the Vaccine Safety Datalink born from 2004 to 2008, we analyzed the association between the timing of childhood vaccination and the first occurrence of seizure with a self-controlled case series analysis of the first doses of individual vaccines received in the first 2 years of life.RESULTS: In infants, there was no association between the timing of infant vaccination and postvaccination seizures. In the second year of life, the incident rate ratio (IRR) for seizures after receipt of the first measles-mumps-rubella vaccine (MMR) dose at 12 to 15 months was 2.65 (95% confidence interval [CI] 1.99-3.55); the IRR after an MMR dose at 16 to 23 months was 6.53 (95% CI 3.15-13.53). The IRR for seizures after receipt of the first measles-mumps-rubella-varicella vaccine (MMRV) dose at 12 to 15 months was 4.95 (95% CI 3.68-6.66); the IRR after an MMRV dose at 16 to 23 months was 9.80 (95% CI 4.35 -22.06).CONCLUSIONS: There is no increased risk of postvaccination seizure in infants regardless of timing of vaccination. In year 2, delaying MMR vaccine past 15 months of age results in a higher risk of seizures. The strength of the association is doubled with MMRV vaccine. These findings suggest that on-time vaccination is as safe with regard to seizures as delayed vaccination in the first year of life, and that delayed vaccination in the second year of life is associated with more postvaccination seizures than on-time vaccination.
    Pediatrics. 05/2014;
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    ABSTRACT: In 2008, a diphtheria, tetanus, acellular pertussis, and inactivated poliovirus combined vaccine (DTaP-IPV) was licensed for use in children 4 through 6 years of age. While pre-licensure studies did not demonstrate significant safety concerns, the number vaccinated in these studies was not sufficient to examine the risk of uncommon but serious adverse events. To assess the risk of serious adverse events following DTaP-IPV vaccination. The study was conducted from January 2009 through September 2012 in the Vaccine Safety Datalink (VSD) project. In the VSD, electronic vaccination and encounter data are updated and aggregated weekly as part of ongoing surveillance activities. Based on previous reports and biologic plausibility, eight potential adverse events were monitored: meningitis/encephalitis; seizures; stroke; Guillain-Barré syndrome; Stevens-Johnson syndrome; anaphylaxis; serious allergic reactions other than anaphylaxis; and serious local reactions. Adverse event rates in DTaP-IPV recipients were compared to historical incidence rates in the VSD population prior to 2009. Sequential probability ratio testing was used to analyze the data on a weekly basis. During the study period, 201,116 children received DTaP-IPV vaccine. Ninety-seven percent of DTaP-IPV recipients also received other vaccines on the same day, typically measles-mumps-rubella and varicella vaccines. There was no statistically significant increased risk of any of the eight pre-specified adverse events among DTaP-IPV recipients when compared to historical incidence rates. In this safety surveillance study of more than 200,000 DTaP-IPV vaccine recipients, there was no evidence of increased risk for any of the pre-specified adverse events monitored. Continued surveillance of DTaP-IPV vaccine safety may be warranted to monitor for rare adverse events, such as Guillain-Barré syndrome.
    Vaccine 03/2014; · 3.77 Impact Factor
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    ABSTRACT: A number of studies have described influenza vaccination coverage during pregnancy but few publications have described rates of other vaccinations. To describe vaccination rates during pregnancy in the Vaccine Safety Datalink (VSD), with particular focus on vaccinations contraindicated during pregnancy. Pregnancies ending in 2002 through 2009 and vaccinations administered during these pregnancies were identified in the VSD. Vaccination rates per 1000 pregnancies during the study period were calculated by vaccine type, recommendation category, pregnancy year, maternal age, and trimester. Analyses were conducted in 2012-2013. In the VSD, 669,695 pregnancies and 141,389 vaccinations were identified. Trivalent inactivated influenza (TIV) was the most commonly administered vaccination (174.1 doses per 1000 pregnancies) and was most often administered during the 2nd and 3rd trimesters. The most common vaccines in the "consider if indicated" category were tetanus-diphtheria (6.1 per 1000) and hepatitis B (3.7 per 1000). Contraindicated vaccination was infrequent, and the majority of these were measles-mumps-rubella (MMR) (1.2 per 1000); varicella (1.0 per 1000); and live-attenuated influenza vaccine (LAIV) (0.3 per 1000). Both "consider if indicated" and contraindicated vaccines were more frequently administered during early pregnancy. TIV was the most commonly administered vaccine. With the exception of TIV, other vaccines were most frequently administered during early pregnancy and among younger women, suggesting that vaccination may occur when the woman and/or provider are unaware of the pregnancy. Contraindicated vaccines were infrequently administered during pregnancy; however, given that some women received contraindicated vaccines later in pregnancy, clearer recommendations and improved provider education may be needed.
    American journal of preventive medicine 02/2014; 46(2):150-7. · 4.24 Impact Factor
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    ABSTRACT: School-located influenza vaccination (SLIV) may be instrumental in achieving high vaccination rates among children. Sustainability of SLIV programs may require third-party billing. This study assessed, among parents of elementary school students, the attitudes about SLIV and billing at school, as well as factors associated with being supportive of SLIV. We conducted a survey (April 2010 to June 2010) of parents of 1000 randomly selected primarily low-income children at 20 elementary schools at which SLIV with billing had occurred. Response rate was 70% (n = 699). Eighty-one percent agreed (61% strongly) they "would be okay" with SLIV for their child. Many agreed it was better to get vaccinated at their child's doctor's office because they could take care of other health issues (72%) and the doctor knows the child's medical history (65%). However, an equal percentage (47%) thought the best place for influenza vaccination was the child's doctor's office and the child's school. Twenty-five percent did not want to give health insurance information necessary for billing at school. Factors independently associated with strongly supporting SLIV included parental education of high school or less (relative risk 1.30; 95% confidence interval 1.09-1.58), Hispanic ethnicity (1.25; 1.08-1.45); believing the vaccine is efficacious (1.49; 1.23-1.84); and finding school delivery more convenient (2.37; 1.82-3.45). Having concerns about the safety of influenza vaccine (0.80; 0.72-0.88) and not wanting their child to be vaccinated without a parent (0.74; 0.64-0.83) were negatively associated. The majority of parents were supportive of SLIV, although parental concerns about not being present for vaccination and about the safety and efficacy of the vaccine will need to be addressed.
    Academic pediatrics 01/2014; 14(3):241-8.
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    ABSTRACT: To assess rates of immunization; costs of conducting clinics; and reimbursements for a school-located influenza vaccination (SLIV) program that billed third-party payers. SLIV clinics were conducted in 19 elementary schools in the Denver Public School district (September 2010 to February 2011). School personnel obtained parental consent, and a community vaccinator conducted clinics and performed billing. Vaccines For Children vaccine was available for eligible students. Parents were not billed for any fees. Data were collected regarding implementation costs and vaccine cost was calculated using published private sector prices. Reimbursement amounts were compared to costs. Overall, 30% of students (2784 of 9295) received ≥1 influenza vaccine; 39% (1079 of 2784) needed 2 doses and 80% received both. Excluding vaccine costs, implementation costs were $24.69 per vaccination. The percentage of vaccine costs reimbursed was 62% overall (82% from State Child Health Insurance Program (SCHIP), 50% from private insurance). The percentage of implementation costs reimbursed was 19% overall (23% from private, 27% from Medicaid, 29% from SCHIP and 0% among uninsured). Overall, 25% of total costs (implementation plus vaccine) were reimbursed. A SLIV program resulted in vaccination of nearly one third of elementary students. Reimbursement rates were limited by 1) school restrictions on charging parents fees, 2) low payments for vaccine administration from public payers and 3) high rates of denials from private insurers. Some of these problems might be reduced by provisions in the Affordable Care Act.
    Academic pediatrics 01/2014; 14(3):234-40.
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    ABSTRACT: The self-controlled case series (SCCS) method is often used to examine the temporal association between vaccination and adverse events using only data from patients who experienced such events. Conditional Poisson regression models are used to estimate incidence rate ratios, and these models perform well with large or medium-sized case samples. However, in some vaccine safety studies, the adverse events studied are rare and the maximum likelihood estimates may be biased. Several bias correction methods have been examined in case-control studies using conditional logistic regression, but none of these methods have been evaluated in studies using the SCCS design. In this study, we used simulations to evaluate 2 bias correction approaches-the Firth penalized maximum likelihood method and Cordeiro and McCullagh's bias reduction after maximum likelihood estimation-with small sample sizes in studies using the SCCS design. The simulations showed that the bias under the SCCS design with a small number of cases can be large and is also sensitive to a short risk period. The Firth correction method provides finite and less biased estimates than the maximum likelihood method and Cordeiro and McCullagh's method. However, limitations still exist when the risk period in the SCCS design is short relative to the entire observation period.
    American journal of epidemiology 12/2013; 178(12):1750-9. · 5.59 Impact Factor
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    ABSTRACT: IMPORTANCE The first dose of live attenuated measles-containing vaccines is associated with an increased risk of febrile seizures 7 to 10 days following immunization among 12- to 23-month-old children. The combination measles, mumps, rubella, and varicella vaccine is associated with a 2-fold increased risk of febrile seizures 7 to 10 days following immunization compared with the separately administered measles, mumps, and rubella and varicella vaccines. It is unknown whether the magnitude of these increased risks depends on age at immunization. OBJECTIVE To examine the potential modifying effect of age on the risk of fever and seizures following immunization with measles-containing vaccines. DESIGN, SETTING, AND PARTICIPANTS Retrospective cohort study at 8 Vaccine Safety Datalink sites of a total of 840 348 children 12 to 23 months of age who had received a measles-containing vaccine from 2001 through 2011. EXPOSURES Any measles-containing vaccines and measles-containing vaccines by type. MAIN OUTCOMES AND MEASURES Fever and seizure events occurring during a 42-day postimmunization observation period. RESULTS In the analysis of any measles-containing vaccines, the increased risk of seizures during the 7- to 10-day risk interval, using the remainder of the observation period as the control interval, was significantly greater among older children (relative risk, 6.5; 95% CI, 5.3-8.1; attributable risk, 9.5 excess cases per 10 000 doses; 95% CI, 7.6-11.5) than among younger children (relative risk, 3.4; 95% CI, 3.0-3.9; attributable risk = 4.0 excess cases per 10 000 doses; 95% CI, 3.4-4.6). The relative risk of postimmunization fever was significantly greater among older children than among younger children; however, its attributable risk was not. In the analysis of vaccine type, measles, mumps, rubella, and varicella vaccine was associated with a 1.4-fold increase in the risk of fever and 2-fold increase in the risk of seizures compared with measles, mumps, and rubella vaccine administered with or without varicella vaccine in both younger and older children. CONCLUSIONS AND RELEVANCE Measles-containing vaccines are associated with a lower increased risk of seizures when administered at 12 to 15 months of age. Findings of this study that focused on safety outcomes highlight the importance of timely immunization of children with the first dose of measles-containing vaccines.
    JAMA pediatrics. 10/2013;
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    ABSTRACT: IMPORTANCE Undervaccination is an increasing trend that potentially places children and their communities at an increased risk for serious infectious diseases. OBJECTIVE To examine the association between undervaccination and pertussis in children 3 to 36 months of age. DESIGN Matched case-control study with conditional logistic regression analysis. SETTING Eight managed care organizations of the Vaccine Safety Datalink between 2004 and 2010. PARTICIPANTS Each laboratory-confirmed case of pertussis (72 patients) was matched to 4 randomly selected controls (for a total of 288 controls). The case patients were matched to controls by managed care organization site, sex, and age at the index date. The index date was defined as the date of pertussis diagnosis for the case patients. EXPOSURE Undervaccination for the diphtheria, tetanus toxoids, and acellular pertussis (DTaP) vaccine. Undervaccination was defined as the number of doses of DTaP vaccine that was either missing or delayed by the index date. Case patients and controls could be undervaccinated by 0, 1, 2, 3, or 4 doses of DTaP vaccine. Children undervaccinated by 0 doses were considered age-appropriately vaccinated by the index date. MAIN OUTCOME AND MEASURE Pertussis. RESULTS Of the 72 case patients with pertussis, 12 (16.67%) were hospitalized, and 34 (47.22%) were undervaccinated for DTaP vaccine by the date of pertussis diagnosis. Of the 288 matched controls, 64 (22.22%) were undervaccinated for DTaP vaccine. Undervaccination was strongly associated with pertussis. Children undervaccinated for 3 or 4 doses of DTaP vaccine were 18.56 (95% CI, 4.92-69.95) and 28.38 (95% CI, 3.19-252.63) times more likely, respectively, to have received a diagnosis of pertussis than children who were age-appropriately vaccinated. CONCLUSIONS AND RELEVANCE Undervaccination with DTaP vaccine increases the risk of pertussis among children 3 to 36 months of age.
    JAMA pediatrics. 09/2013;
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    ABSTRACT: Previously published studies reported an increased risk of gastrointestinal illness in the 14 days following trivalent influenza vaccination (TIV) in young children. While gastrointestinal illness may be a true adverse effect of TIV, other factors may influence this observed association, such as seasonal illness patterns and children being exposed to gastrointestinal pathogens at medical visits. The objective of this study was to examine factors influencing the association between TIV and gastrointestinal illness. Specifically, using data from a previous influenza vaccine safety study, we examined the association between medical encounters without TIV and gastrointestinal illness. Using electronic health record (EHR) data from 6 managed care organizations (MCOs), we identified medically attended gastrointestinal illness cases among children 24-59 months in the 2002-2006 influenza seasons. We matched each case to four controls on sex, birthdate (month/year), MCO, influenza season, and presence of a chronic condition. We then looked 1-14 days prior to the index date (gastrointestinal illness diagnosis date) to determine whether the child had a medical encounter. We excluded previous medical encounters with gastrointestinal-related diagnoses or TIV. Conditional logistic regression was used to calculate odds ratios and 95% confidence intervals. We identified 2062 gastrointestinal illness cases and matched them to 8248 controls. We observed increased odds of gastrointestinal illness within 14 days after a medical encounter (odds ratio=1.9; 95% confidence interval [CI]: 1.7-2.2) among children without chronic conditions. Among children with chronic conditions, the odds ratio was 3.9 (95% CI: 2.5-6.2). We demonstrated that another exposure related to vaccination, medical visits, is also associated with increased odds for gastrointestinal illness. This study highlights challenges of interpreting results from observational vaccine safety studies when there are co-occurring exposures, and the importance of investigating confounding in EHR data, which are an essential resource for vaccine safety research.
    Vaccine 07/2013; · 3.77 Impact Factor
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    ABSTRACT: OBJECTIVE:: To estimate the risks for medically attended events occurring within 42 days of receiving trivalent inactivated influenza vaccine and to evaluate specific risks of first-trimester vaccination. METHODS:: This retrospective observational cohort study compared rates of medically attended adverse events in trivalent inactivated influenza-vaccinated and unvaccinated pregnant women in the Vaccine Safety Datalink. Using a Poisson distribution and log link, we calculated maternal adjusted incident rate ratios for composite safety outcomes for the full cohort and the subset vaccinated during the first trimester. RESULTS:: The cohort included 75,906 vaccinated (28.4% in the first trimester) and 147,992 unvaccinated women matched by age, site, and pregnancy start date. In the first 3 days after vaccination, trivalent inactivated influenza vaccine was not associated with increased risk of specified medically attended events, including allergic reactions, cellulitis, and seizures (full cohort adjusted incident rate ratio 1.12, 95% confidence interval [CI] 0.81-1.55; P=.48; first-trimester adjusted incident rate ratio .97, 95% CI 0.53-1.78; P=.93). In the first 42 days, no incident cases of Guillain-Barré syndrome, optic neuritis, transverse myelitis, or Bells palsy were identified. Trivalent inactivated influenza vaccine was not associated with thrombocytopenia (full cohort adjusted incident rate ratio 0.90, 95% CI 0.68--1.19; P=.45; first-trimester adjusted incident rate ratio 0.56, 95% CI 0.22-1.39; P=.21) or an acute neurologic event (full cohort adjusted incident rate ratio 0.92, 95% CI 0.54-1.6; P=.75; first-trimester adjusted incident rate ratio 1.05, 95% CI 0.46-2.38; P=.91). CONCLUSIONS:: Receipt of trivalent inactivated influenza vaccine during pregnancy was not associated with increased risk of adverse events in the 42 days after vaccination, supporting its safety for the mother. LEVEL OF EVIDENCE:: II.
    Obstetrics and Gynecology 03/2013; 121(3):519-525. · 4.80 Impact Factor
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    ABSTRACT: OBJECTIVES To examine patterns and trends of undervaccination in children aged 2 to 24 months and to compare health care utilization rates between undervaccinated and age-appropriately vaccinated children. DESIGN Retrospective matched cohort study. SETTING Eight managed care organizations of the Vaccine Safety Datalink. PARTICIPANTS Children born between 2004 and 2008. MAIN EXPOSURE Immunization records were used to calculate the average number of days undervaccinated. Two matched cohorts were created: 1 with children who were undervaccinated for any reason and 1 with children who were undervaccinated because of parental choice. For both cohorts, undervaccinated children were matched to age-appropriately vaccinated children by birth date, managed care organization, and sex. MAIN OUTCOME MEASURES Rates of undervaccination, specific patterns of undervaccination, and health care utilization rates. RESULTS Of 323 247 children born between 2004 and 2008, 48.7% were undervaccinated for at least 1 day before age 24 months. The prevalence of undervaccination and specific patterns of undervaccination increased over time (P < .001). In a matched cohort analysis, undervaccinated children had lower outpatient visit rates compared with children who were age-appropriately vaccinated (incidence rate ratio [IRR], 0.89; 95% CI, 0.89- 0.90). In contrast, undervaccinated children had increased inpatient admission rates compared with age-appropriately vaccinated children (IRR, 1.21; 95% CI, 1.18-1.23). In a second matched cohort analysis, children who were undervaccinated because of parental choice had lower rates of outpatient visits (IRR, 0.94; 95% CI, 0.93-0.95) and emergency department encounters (IRR, 0.91; 95% CI, 0.88-0.94) than age-appropriately vaccinated children. CONCLUSIONS Undervaccination appears to be an increasing trend. Undervaccinated children appear to have different health care utilization patterns compared with age-appropriately vaccinated children.
    JAMA pediatrics. 01/2013;
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    ABSTRACT: OBJECTIVE:Our objective was to assess whether the occurrence of medically attended local reactions to intramuscularly administered vaccines varies by injection site (arm versus thigh) in children 1 to 6 years of age.METHODS:This is a retrospective cohort study of children in the Vaccine Safety Datalink population from 2002 to 2009. Site of injection and the outcome of medically attended local reactions were identified from administrative data.RESULTS:The study cohort of 1.4 million children received 6.0 million intramuscular (IM) vaccines during the study period. The primary analyses evaluated the IM vaccines most commonly administered alone, which included inactivated influenza, hepatitis A, and diphtheria-tetanus-acellular pertussis (DTaP) vaccines. For inactivated influenza and hepatitis A vaccines, local reactions were relatively uncommon, and there was no difference in risk of these events with arm versus thigh injections. The rate of local reactions after DTaP vaccines was higher, and vaccination in the arm was associated with a significantly greater risk of this outcome compared with vaccination in the thigh, both for children 12 to 35 months (relative risk: 1.88 [95% confidence interval: 1.34-2.65]) and 3 to 6 years of age (relative risk: 1.41 [95% confidence interval: 0.84-2.34]), although this difference was not statistically significant in the older age group.CONCLUSIONS:Injection in the thigh is associated with a significantly lower risk of a medically attended local reaction to a DTaP vaccination among children 12 to 35 months of age, supporting current recommendations to administer IM vaccinations in the thigh for children younger than 3 years of age.
    PEDIATRICS 01/2013; · 4.47 Impact Factor
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    ABSTRACT: In the examination of the association between vaccines and rare adverse events after vaccination in postlicensure observational studies, it is challenging to define appropriate risk windows because prelicensure RCTs provide little insight on the timing of specific adverse events. Past vaccine safety studies have often used prespecified risk windows based on prior publications, biological understanding of the vaccine, and expert opinion. Recently, a data-driven approach was developed to identify appropriate risk windows for vaccine safety studies that use the self-controlled case series design. This approach employs both the maximum incidence rate ratio and the linear relation between the estimated incidence rate ratio and the inverse of average person time at risk, given a specified risk window. In this paper, we present a scan statistic that can identify appropriate risk windows in vaccine safety studies using the self-controlled case series design while taking into account the dependence of time intervals within an individual and while adjusting for time-varying covariates such as age and seasonality. This approach uses the maximum likelihood ratio test based on fixed-effects models, which has been used for analyzing data from self-controlled case series design in addition to conditional Poisson models. Copyright © 2013 John Wiley & Sons, Ltd.
    Statistics in Medicine 01/2013; · 2.04 Impact Factor
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    ABSTRACT: BACKGROUND: The primary prevention measure for influenza infection has been the use of influenza vaccines. However, even when the vaccine and circulating strains are well-matched, some healthy children do not respond to the vaccine, likely due to a genetic basis for immune hyporesponsiveness. The primary objective of this study was to identify HLA class II genes associated with clinical hyporesponsiveness after trivalent inactivated influenza vaccine (TIV) in children. METHODS: We conducted a case-control study nested within a retrospective cohort of children that were screened at birth for HLA-DR,DQ genotypes by the Diabetes Autoimmunity Study in the Young (DAISY) and were subsequently followed for up to 8 years by Kaiser Permanente, Colorado (KPCO). Hyporesponsiveness was clinically defined as the occurrence of influenza or influenza-like illness (ILI) in peak influenza weeks in children fully vaccinated with TIV. Each child with clinical hyporesponse (n=252) was matched to 4 randomly selected controls (n=1006) by age and season. Children with clinical hyporesponse to TIV were identified using the Kaiser electronic clinical and immunization databases. Fully vaccinated children within the KPCO-DAISY cohort who did not have a diagnosis of ILI during the entire influenza season were eligible to be controls for that season. Class II HLA-DRB1 and HLA-DQB1 genes were the primary exposure variables. We used conditional logistic regression to calculate the matched odds ratios. RESULTS: In non-Hispanic white children, HLA-DR7/4,DQB1*0302 genotype was significantly associated (OR=5.15; 95% CI=1.94, 13.67; p=0.001), while in Hispanic children, HLA-DRB1*15 or 16 allele (OR=0.31; 95% CI=0.14, 0.69; p=0.004) and HLA-DR7/Y (DRB1*11, DRB1*13 and DRB1*14) genotype (OR=5.84; 95% CI=1.68, 20.28; p=0.006) were significantly associated with clinical hyporesponsiveness after TIV. CONCLUSIONS: HLA class II genes are associated with clinical hyporesponsiveness to TIV. This finding is important as it may help identify a group of children who are not protected by the commonly used TIV and may require alternative preventive strategies.
    Vaccine 12/2012; · 3.77 Impact Factor
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    ABSTRACT: OBJECTIVE:To assess physician attitudes regarding school-located adolescent vaccination and influenza vaccination.METHODS:From July through September 2010, a 20-item survey was mailed to 1337 practicing Colorado family physicians and pediatricians. Standard statistical methods were used to examine unadjusted and adjusted odds ratios of factors associated with physician support for school-located vaccination programs.RESULTS:Overall, 943 physicians were survey-eligible, and 584 (62%) responded. More than half of physicians supported both school-located influenza and adolescent vaccination. However, fewer physicians supported school-located adolescent vaccination compared with influenza vaccination. More physicians supported school-located vaccination for their publicly insured patients compared with their privately insured patients. Some family physicians (32%) and pediatricians (39%) believed that school-located vaccination would make their patients less likely to attend well-child visits, and half of respondents believed that school-located vaccination would have a negative financial impact on their practice. In multivariate analyses, physicians concerned about the financial impact of school-located vaccination were less likely to support such programs.CONCLUSIONS:Although a majority of Colorado physicians supported influenza and adolescent vaccination at school, they expressed concerns regarding the implications on their practice. Lesser support for vaccination of their privately insured patients and concerns regarding attendance at well-child visits suggests the perceived financial impact from school-located vaccination is a barrier and merits additional examination.
    PEDIATRICS 10/2012; · 4.47 Impact Factor
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    ABSTRACT: In 2008 the Advisory Committee on Immunization Practices (ACIP) of the Centers for Disease Control and Prevention (CDC) recommended that all children aged 6 months to 18 years receive annual influenza vaccine. Full pediatric influenza administration has proven difficult. We compared rates of full influenza immunization between a safety net health care system and CDC sentinel sites and evaluated sociodemographic factors associated with full influenza immunization. We matched influenza immunization data for 2008-2009 from a health care system immunization registry with patient demographic/billing data and compared rates to CDC sentinel sites using bivariate analysis. We evaluted immunization rates by patient characteristics using multivariate analysis. Full influenza immunization was achieved in 32% of Denver Health (DH) children compared to 12% at the CDC sites (p<0.001). The largest differences occurred in children aged 11-12 and 13-18 years, 47% DH vs 12% CDC sites, and 33% DH vs 9% CDC sites respectively, (p<0.001 for both). In multivariate analysis, DH children were more likely to be immunized if they were Asian, Odds Ratio (OR) 1.59 95%CI (CI) 1.32-1.91, or Hispanic OR 1.18 CI 1.07-1.30, compared to white, spoke Spanish OR 1.19 CI 1.13-1.26, or other non-English language OR 2.05 CI 1.80-2.34, and had a greater number of visits for well care OR 2.86 CI 2.74-2.98 and sick/follow-up care OR 1.59 CI 1.56-1.62, during the influenza season. They were less likely to be immunized if they had commercial insurance OR 0.68 CI 0.62-0.75 or were uninsured OR 0.77 CI 0.72-0.80, compared to Medicaid/SCHIP. Using immunization registry prompts, standing orders, multiple sites and visit types for immunization, an integrated safety net health care system had higher full influenza immunization rates than the CDC sentinel sites singularly or collectively. These procedures can be applied elsewhere to improve influenza immunization rates.
    Vaccine 03/2012; 30(19):2951-5. · 3.77 Impact Factor
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    ABSTRACT: Current rotavirus vaccines were not associated with intussusception in large prelicensure trials. However, recent postlicensure data from international settings suggest the possibility of a low-level elevated risk, primarily in the first week after the first vaccine dose. To examine the risk of intussusception following pentavalent rotavirus vaccine (RV5) in US infants. This cohort study included infants 4 to 34 weeks of age, enrolled in the Vaccine Safety Datalink (VSD) who received RV5 from May 2006-February 2010. We calculated standardized incidence ratios (SIRs), relative risks (RRs), and 95% confidence intervals for the association between intussusception and RV5 by comparing the rates of intussusception in infants who had received RV5 with the rates of intussusception in infants who received other recommended vaccines without concomitant RV5 during the concurrent period and with the expected number of intussusception visits based on background rates assessed prior to US licensure of the RV5 (2001-2005). Intussusception occurring in the 1- to 7-day and 1- to 30-day risk windows following RV5 vaccination. During the study period, 786,725 total RV5 doses, which included 309,844 first doses, were administered. We did not observe a statistically significant increased risk of intussusception with RV5 for either comparison group following any dose in either the 1- to 7-day or 1- to 30-day risk window. For the 1- to 30-day window following all RV5 doses, we observed 21 cases of intussusception compared with 20.9 expected cases (SIR, 1.01; 95% CI, 0.62-1.54); following dose 1, we observed 7 cases compared with 5.7 expected cases (SIR, 1.23; 95% CI, 0.5-2.54). For the 1- to 7-day window following all RV5 doses, we observed 4 cases compared with 4.3 expected cases (SIR, 0.92; 95% CI, 0.25-2.36); for dose 1, we observed 1 case compared with 0.8 expected case (SIR, 1.21; 95% CI, 0.03-6.75). The upper 95% CI limit of the SIR (6.75) from the historical comparison translates to an upper limit for the attributable risk of 1 intussusception case per 65,287 RV5 dose-1 recipients. Among US infants aged 4 to 34 weeks who received RV5, the risk of intussusception was not increased compared with infants who did not receive the rotavirus vaccine.
    JAMA The Journal of the American Medical Association 02/2012; 307(6):598-604. · 29.98 Impact Factor
  • JAMA The Journal of the American Medical Association 01/2012; · 29.98 Impact Factor

Publication Stats

672 Citations
258.04 Total Impact Points


  • 2006–2014
    • Kaiser Permanente
      • Center for Health Research (Oregon, Hawaii, and Georgia)
      Oakland, California, United States
    • University of Utah
      • Department of Pediatrics
      Salt Lake City, UT, United States
  • 2004–2014
    • University of Colorado
      • Department of Pediatrics
      Denver, Colorado, United States
  • 2012
    • Harvard University
      • Department of Epidemiology
      Cambridge, MA, United States
  • 2011–2012
    • Community Health Systems Professional Services Corporation
      Franklin, Tennessee, United States
    • Centers for Disease Control and Prevention
      • Immunization Safety Office
      Druid Hills, GA, United States
  • 2002
    • Denver Health and Hospital Authority
      Denver, Colorado, United States