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1.  Passive Cigarette Smoke Exposure and Other Risk Factors for Invasive Pneumococcal Disease in Children: A Case-Control Study 
The Permanente Journal  2015;19(1):38-43.
In a population-based, case-control study, 171 children, aged 0 to 12 years, with culture-confirmed invasive pneumococcal disease during the years 1994 to 2004 were identified. Two controls were matched to each case. The authors reviewed medical records of subjects and family members for information on household cigarette smoke exposure within 2 years of the diagnosis. Passive cigarette smoke exposure was not associated with invasive pneumococcal disease in this pediatric population.
To investigate whether passive cigarette smoke exposure increases the risk of invasive pneumococcal disease in children.
In a population-based case-control study, 171 children aged 0 to 12 years with culture-confirmed invasive pneumococcal disease during the years 1994 to 2004 were identified. Two controls were matched to each case on age and patterns of Health Plan membership. We reviewed medical records of subjects and family members for information on household cigarette smoke exposure within 2 years of the diagnosis of invasive pneumococcal disease. We collected information on sex, race, pneumococcal vaccination, selected medical conditions, and medications in the 3 months before the diagnosis.
Similar proportions of cases (25%) and controls (30%) had definite or probable passive smoke exposure (odds ratio [OR] = 0.76, 95% confidence interval [CI] = 0.47–1.2). Cases of invasive pneumococcal disease were more likely to be nonwhite than controls (OR = 4.4, 95% CI = 2.3–8.2). Elevated risk of invasive pneumococcal disease was found in subjects with recent pulmonary diagnoses (OR = 2.2, 95% CI = 1.2–4.0) and recent antibiotic use (OR = 1.6, 95% CI = 1.1–2.3).
Passive cigarette smoke exposure was not associated with invasive pneumococcal disease in this pediatric population. Invasive pneumococcal disease was associated with recent pulmonary diagnoses and recent antibiotic use.
PMCID: PMC4315375  PMID: 25431997
2.  Identification and characteristics of vaccine refusers 
BMC Pediatrics  2009;9:18.
This study evaluated the utility of immunization registries in identifying vaccine refusals among children. Among refusers, we studied their socioeconomic characteristics and health care utilization patterns.
Medical records were reviewed to validate refusal status in the immunization registries of two health plans. Racial, education, and income characteristics of children claiming refusal were collected based on the census tract of each child. Health care utilization was identified using both electronic medical record and insurance claims. Within the immunization registries of two HMOs in the study, some providers use refusal and medical contraindication interchangeably, and some providers tend to always use "ever refusal." Therefore, we combined medical contraindication and refusal together and treated them all as "refusal" in this study.
The immunization registry, compared to chart review, had negative predictive values of 85–92% and 90–97% for 2- and 6-year olds, and positive predictive values of only 52–74% and 59–62% to identify vaccine refusals. Refusers were more likely to reside in well-educated, higher income areas than non-refusers. Refusers had not opted out of health care system and continued, although less frequently for the age 2 and under group, to use services.
Without enhancements to immunization registries, identifying children with immunization refusal would be time consuming. Since communities where refusers live are well educated, interventions should target these communities to communicate vaccine adverse events and consequences of vaccine preventable diseases.
PMCID: PMC2667392  PMID: 19261196
3.  Variation in hepatitis B immunization coverage rates associated with provider practices after the temporary suspension of the birth dose 
BMC Pediatrics  2006;6:31.
In 1999, the American Academy of Pediatrics and U.S. Public Health Service recommended suspending the birth dose of hepatitis B vaccine due to concerns about potential mercury exposure. A previous report found that overall national hepatitis B vaccination coverage rates decreased in association with the suspension. It is unknown whether this underimmunization occurred uniformly or was associated with how providers changed their practices for the timing of hepatitis B vaccine doses. We evaluate the impact of the birth dose suspension on underimmunization for the hepatitis B vaccine series among 24-month-olds in five large provider groups and describe provider practices potentially associated with underimmunization following the suspension.
Retrospective cohort study of children enrolled in five large provider groups in the United States (A-E). Logistic regression was used to evaluate the association between the birth dose suspension and a child's probability of being underimmunized at 24 months for the hepatitis B vaccine series.
Prior to July 1999, the percent of children who received a hepatitis B vaccination at birth varied widely (3% to 90%) across the five provider groups. After the national recommendation to suspend the hepatitis B birth dose, the percent of children who received a hepatitis B vaccination at birth decreased in all provider groups, and this trend persisted after the policy was reversed. The most substantial decreases were observed in the two provider groups that shifted the first hepatitis B dose from birth to 5–6 months of age. Accounting for temporal trend, children in these two provider groups were significantly more likely to be underimmunized for the hepatitis B series at 24 months of age if they were in the birth dose suspension cohort compared with baseline (Group D OR 2.7, 95% CI 1.7 – 4.4; Group E OR 3.1, 95% CI 2.3 – 4.2). This represented 6% more children in Group D and 9% more children in Group E who were underimmunized in the suspension cohort compared with baseline. Children in the reversal cohort in these groups remained significantly more likely to be underimmunized compared with baseline. In contrast, in a third provider group where the typical timing of the third dose was unchanged and in two other provider groups whose hepatitis B vaccination schedules were unaffected by the birth dose suspension, hepatitis B vaccination coverage either was maintained or improved.
When the hepatitis B birth dose was suspended, provider groups that moved the first dose of vaccination to 5–6 months of age or later had decreases in hepatitis B vaccine coverage at 24 months. These findings suggest that as vaccine policy changes occur, providers could attempt to minimize underimmunization by adopting vaccination schedules that minimize delays in the recommended timing of vaccine doses.
PMCID: PMC1657005  PMID: 17101052
4.  Impact of the introduction of pneumococcal conjugate vaccine on immunization coverage among infants 
BMC Pediatrics  2005;5:43.
The introduction of pneumococcal conjugate vaccine (PCV) to the U.S. recommended childhood immunization schedule in the year 2000 added three injections to the number of vaccinations a child is expected to receive during the first year of life. Surveys have suggested that the addition of PCV has led some immunization providers to move other routine childhood vaccinations to later ages, which could increase the possibility of missing these vaccines. The purpose of this study was to evaluate whether introduction of PCV affected immunization coverage for recommended childhood vaccinations among 13-month olds in four large provider groups.
In this retrospective cohort study, we analyzed computerized data on vaccinations for 33,319 children in four large provider groups before and after the introduction of PCV. The primary outcome was whether the child was up to date for all non-PCV recommended vaccinations at 13 months of age. Logistic regression was used to evaluate the association between PCV introduction and the primary outcome. The secondary outcome was the number of days spent underimmunized by 13 months. The association between PCV introduction and the secondary outcome was evaluated using a two-part modelling approach using logistic and negative binomial regression.
Overall, 93% of children were up-to-date at 13 months, and 70% received all non-PCV vaccinations without any delay. Among the entire study population, immunization coverage was maintained or slightly increased from the pre-PCV to post-PCV periods. After multivariate adjustment, children born after PCV entered routine use were less likely to be up-to-date at 13 months in one provider group (Group C: OR = 0.5; 95% CI: 0.3 – 0.8) and were less likely to have received all vaccine doses without any delay in two Groups (Group B: OR = 0.4, 95% CI: 0.3 – 0.6; Group C: OR = 0.5, 95% CI: 0.4 – 0.7). This represented 3% fewer children in Group C who were up-to-date and 14% (Group C) to 16% (Group B) fewer children who spent no time underimmunized at 13 months after PCV entered routine use compared to the pre-PCV baseline. Some disruptions in immunization delivery were also observed concurrent with temporary recommendations to suspend the birth dose of hepatitis B vaccine, preceding the introduction of PCV.
These findings suggest that the introduction of PCV did not harm overall immunization coverage rates in populations with good access to primary care. However, we did observe some disruptions in the timely delivery of other vaccines coincident with the introduction of PCV and the suspension of the birth dose of hepatitis B vaccine. This study highlights the need for continued vigilance in coming years as the U.S. introduces new childhood vaccines and policies that may change the timing of existing vaccines.
PMCID: PMC1314888  PMID: 16313673
5.  Detecting Possible Vaccination Reactions in Clinical Notes 
The Vaccine Safety Datalink is a collaboration between the CDC and eight large HMO’s to investigate adverse events following immunization through analysis of medical care databases and patients’ medical charts. We modified an existing system called MediClass that uses natural language processing (NLP) and knowledge-based methods to classify clinical encounters recorded in electronic medical records (EMRs). We developed the knowledge necessary for MediClass to detect possible vaccine reactions in the outpatient, ED, and telephone encounters recorded in the EMR of a large HMO. We first trained the system using a manually coded gold standard training set, and achieved high sensitivity and specificity. We then ran a large set of post-immunization encounter records through MediClass to see if our method would generalize. Compared to methods that use administrative and clinical codes assigned to the EMR by clinicians, the system significantly improves the positive predictive value for detecting possible vaccine reactions.
PMCID: PMC1560600  PMID: 16779051
6.  Primary Care Physicians' Use of Lumbar Spine Imaging Tests 
To reduce variability in primary care physicians' use of procedures for imaging the lumbar spine.
Controlled intervention using clinical practice guideline and practice pattern feedback.
Sixty-seven internists and 28 family practitioners in a large, group-model HMO.
Intervention group physicians received the clinical practice guideline for low back pain, followed after 4 months by three bimonthly feedback reports on their current use rates for lumber spine x-rays and computed tomography and magnetic resonance imaging scans of the lumbar spine. Control group physicians received neither the guideline nor the feedback reports. Automated radiology utilization data were used to compare intervention and control group physicians' changes in use rates and variability in use rates over the course of the study period. Neither the guideline alone nor the guideline plus feedback was associated with a significant decrease in use rates or in the variability in use rates for the lumbar spine imaging procedures under study.
Clinical practice guidelines and practice pattern feedback fail to achieve their goals when features of the practice setting and patient expectations and behavior are not identified and addressed.
PMCID: PMC1497173  PMID: 9346458
low back pain; treatment; clinical practice guidelines; practice pattern feedback

Results 1-6 (6)