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The Vaccine Safety Datalink (VSD) is a collaboration between the CDC and eight large HMOs to investigate adverse events following immunization through analyses of clinical data. We modified an existing system, called MediClass, that uses natural language processing to identify clinical events recorded in electronic medical records (EMRs). We customized MediClass so it could detect possible vaccine adverse events (VAEs) generally, and gastrointestinal-related VAEs in particular, in the text clinical notes of encounters recorded in the EMR of a large HMO. Compared to methods that use diagnosis and utilization codes assigned to encounters by clinicians and administrators, the MediClass system can both find more adverse events and improve the positive predictive value for detecting possible VAEs.

We assessed the contribution of telephone medical care encounters to surveillance of adverse events (AE) following trivalent influenza vaccination in children age 6 months to 17 years. We used retrospective, self-controlled, case-series analysis to estimate adverse event incidence rate ratios for post-vaccination risk intervals relative to 15-28 days prior to vaccination. We confirmed possible vaccination reactions by medical record abstraction. Detection of 10 of 20 elevated incidence rate ratios required telephone data. We conclude that telephone encounters substantially contribute to the detection of possible influenza vaccination reactions, primarily local injection site and systemic reactions.

Studies assessing the clinical and economic benefits of vaccination in the elderly have used different clinical outcomes (e.g. hospitalizations for pneumonia or influenza versus hospitalizations for respiratory and cardiovascular causes) and different outcome periods (e.g. peak versus total influenza season) on which to base estimates of clinical effectiveness and cost effectiveness. We explored the implications of these varying approaches by comparing two health economic analysis models of influenza vaccination of community-dwelling elderly persons. We developed computerized models using clinical data from 3 large US HMOs for the 1998-1999 and 1999-2000 influenza seasons. The primary health economic model used a broad definition of clinical events and outcome period and included hospitalizations for all respiratory and cardiovascular events that occurred during the entire influenza season. The alternative model used more restrictive definitions and included pneumonia or influenza hospitalizations occurring during the peak influenza season. The results of Monte Carlo simulation showed that, with the more inclusive primary model, influenza vaccination resulted in net medical care cost savings due to fewer respiratory or cardiovascular hospitalizations of Dollars 71/person vaccinated (5th-95th percentile Dollars 32-118) and net savings of Dollars 809/year of life saved (5th-95th percentile Dollars 331-1450). In contrast, the alternate model found costs of Dollars 3.50/person vaccinated (5th-95th percentile Dollars -11 to 5) and net costs of Dollars 91/year of life saved (5th-95th percentile Dollars -309 to 126). Our findings confirm that influenza vaccination of the elderly is most likely cost saving and supports policies and programs that advocate routine immunization of all persons 65 and older. They also highlight how different outcome definitions can influence the results of health economic analyses.

There is little information on the safety of administration of a third dose of pneumococcal polysaccharide vaccine (PPV). The authors conducted a retrospective assessment of 316,995 adult members of three health maintenance organizations who had received one, two, or three PPV doses. Medical encounters associated with diagnosis codes potentially indicative of an injection site reaction in the week following a first, second, or third PPV dose were identified. These presumptive events occurred in 0.3% (911/279504) of the first PPV group, 0.7% (257/36888) of the second PPV group, and 0.5% (3/603) of the third PPV group (p>0.5 for both comparisons with the third PPV group). These findings do not suggest that a third PPV dose is associated with an increased risk of medically attended injection site reactions compared with a first or second PPV dose.

Background: Although effects of maternal smoking during pregnancy could be alleviated if women quit early in pregnancy, most do not. Relapse rates among quitters are high., Objective: To test the effects of a low-intensity, smoking-cessation/relapse-prevention intervention delivered by clinic staff and providers and based on stages-of-change constructs of the transtheoretical model and brief motivational interviewing techniques., Methods: A quasi-experimental prospective cohort design employed in obstetric, in-patient, and pediatric care delivery settings of a large health maintenance organization in Portland, Oregon. Subjects were pregnant smokers registered for their first prenatal visit. Primary outcome measures were sustained (self-reported) quit rates during pregnancy and smoking abstinence between 6 and 12 months after delivery., Results: Regression analyses found statistically significant improvement for intervention women in sustained pregnancy quit rates (OR=2.7, CI=1. 2-5.7) and on smoking abstinence between 6 and 12 months after delivery (OR=2.4, CI=1.1-5.3)., Conclusions: While these outcomes are based on self-report only, they emerged despite variable delivery of the intervention across clinics and represent clinically meaningful improvements in rates of nonsmoking. The intervention supports women who want to quit smoking during pregnancy and improves the likelihood of their remaining nonsmokers for the long term.

We assessed vaccination coverage and predictors of influenza vaccination in asthmatic children in four large Health Maintenance Organizations. We studied 68,839 children with asthma at four Health Maintenance Organizations (HMOs) in the 1995-1996 influenza season and 34,032 children at two HMOs in the 1996-1997 influenza season. In both seasons only 9-10% were vaccinated against influenza. Children who were hospitalized, had an emergency department visit for asthma or a prescription for a beta-agonist prior to the influenza season, were more likely to be vaccinated. Overall, 61% of the unvaccinated asthmatic children had made an outpatient clinic visit during months when influenza vaccination would have been appropriate. Vaccination coverage could be increased by taking advantage of all opportunities to vaccinate children with asthma whenever they make clinic visits in the fall and early winter.

Biochemical validation of smoking status has long been considered essential, but recent reports have questioned its utility in certain kinds of field trials. We describe efforts to biochemically validate self-reports of smoking cessation from participants in four large-scale randomized trials in outpatient clinics, hospitals, worksites, and dental clinics. These studies included over 5,000 adults smokers who participated in the population-based low-intensity intervention evaluations. At a 1-year follow-up, 798 subjects reported no tobacco use. We attempted to verify these reports using saliva continine/carbon monoxide validation procedures. Overall, there was a moderately high nonparticipation rate (27%), a low disconfirmation rate (4%), and a high self-reported relapse rate (12%) in the interval between survey and biochemical validation. There were no differences between intervention and control conditions on any of the above variables. Longer durations of self-reported abstinence were strongly related to increased probability of biochemical confirmation. Differences in results across projects were related to how biochemical validation was conducted. These results, as well as statistical power considerations, raise questions about whether biochemical validation procedures are practical, informative, or cost-effective in such population-based, low-intensity intervention research.