[Show abstract][Hide abstract] ABSTRACT: We sought to measure trends in Streptococcus pneumoniae carriage and antibiotic resistance in young children in Massachusetts communities after widespread adoption of heptavalent 7-valent pneumococcal conjugate vaccine (PCV7) and before the introduction of the 13-valent PCV (PCV13).
We conducted a cross-sectional study including collection of questionnaire data and nasopharyngeal specimens among children aged <7 years in primary care practices from 8 Massachusetts communities during the winter season of 2008-2009 and compared with similar studies performed in 2001, 2003-2004, and 2006-2007. Antimicrobial susceptibility testing and serotyping were performed on pneumococcal isolates, and risk factors for colonization in recent seasons (2006-2007 and 2008-2009) were evaluated.
We collected nasopharyngeal specimens from 1011 children, 290 (29%) of whom were colonized with pneumococcus. Non-PCV7 serotypes accounted for 98% of pneumococcal isolates, most commonly 19A (14%), 6C (11%), and 15B/C (11%). In 2008-2009, newly targeted PCV13 serotypes accounted for 20% of carriage isolates and 41% of penicillin-nonsusceptible S. pneumoniae. In multivariate models, younger age, child care, young siblings, and upper respiratory illness remained predictors of pneumococcal carriage, despite near-complete serotype replacement. Only young age and child care were significantly associated with penicillin-nonsusceptible S. pneumoniae carriage.
Serotype replacement post-PCV7 is essentially complete and has been sustained in young children, with the relatively virulent 19A being the most common serotype. Predictors of carriage remained similar despite serotype replacement. PCV13 may reduce 19A and decrease antibiotic-resistant strains, but monitoring for new serotype replacement is warranted.
Full-text · Article · Dec 2011 · The Pediatric Infectious Disease Journal
[Show abstract][Hide abstract] ABSTRACT: The HMO Research Network (HMORN) is a consortium of 16 health care systems with integrated research centers. Approximately 475 people participated in its 17(th) annual conference, hosted by the Department of Population Medicine, Harvard Pilgrim Health Care Institute and Harvard Medical School. The theme, "Collaborations in Population-Based Health Research," reflected the network's emphasis on collaborative studies both among its members and with external investigators. Plenary talks highlighted the initial phase of the HMORN's work to establish the NIH-HMO Collaboratory, opportunities for public health collaborations, the work of early career investigators, and the state of the network. Platform and poster presentations showcased a broad spectrum of innovative public domain research in areas including disease epidemiology and treatment, health economics, and information technology. Special interest group sessions and ancillary meetings provided venues for informal conversation and structured work among ongoing groups, including networks in cancer, cardiovascular diseases, lung diseases, medical product safety, and mental health.
Preview · Article · Nov 2011 · Clinical Medicine & Research
[Show abstract][Hide abstract] ABSTRACT: Many studies have evaluated methicillin-resistant Staphylococcus aureus (MRSA) infections during single hospitalizations and subsequent readmissions to the same institution. None have assessed the comprehensive burden of MRSA infection in the period after hospital discharge while accounting for healthcare utilization across institutions.
We conducted a retrospective cohort study of adult patients insured by Harvard Pilgrim Health Care who were newly-detected to harbor MRSA between January 1991 and December 2003 at a tertiary care medical center. We evaluated all MRSA-attributable infections associated with hospitalization in the year following new detection, regardless of hospital location. Data were collected on comorbidities, healthcare utilization, mortality and MRSA outcomes. Of 591 newly-detected MRSA carriers, 23% were colonized and 77% were infected upon detection. In the year following detection, 196 (33%) patients developed 317 discrete and unrelated MRSA infections. The most common infections were pneumonia (34%), soft tissue (27%), and primary bloodstream (18%) infections. Infections occurred a median of 56 days post-detection. Of all infections, 26% involved bacteremia, and 17% caused MRSA-attributable death. During the admission where MRSA was newly-detected, 14% (82/576) developed subsequent infection. Of those surviving to discharge, 24% (114/482) developed post-discharge infections in the year following detection. Half (99/185, 54%) of post-discharge infections caused readmission, and most (104/185, 55%) occurred over 90 days post-discharge.
In high-risk tertiary care patients, newly-detected MRSA carriage confers large risks of infection and substantial attributable mortality in the year following acquisition. Most infections occur post-discharge, and 18% of infections associated with readmission occurred in hospitals other than the one where MRSA was newly-detected. Despite gains in reducing MRSA infections during hospitalization, the risk of MRSA infection among critically and chronically ill carriers persists after discharge and warrants targeted prevention strategies.
[Show abstract][Hide abstract] ABSTRACT: Recent increases in patient cost-sharing for health care have lent increasing importance to monitoring cost-related changes in health care use. Despite the widespread use of survey questions to measure changes in health care use and related behaviors, scant data exists on the reliability of such questions.
We administered a cross-sectional survey to a stratified random sample of families in a New England health plan's high deductible health plan (HDHP) with ≥ $500 in annualized out-of-pocket expenditures. Enrollees were asked about their knowledge of their plan, information seeking, behavior change associated with having a deductible, experience of delay in care due in part to cost, and hypothetical delay in care due in part to cost. Initial respondents were mailed a follow-up survey within two weeks of each family returning the original survey. We computed several agreement statistics to measure the test-retest reliability for select questions. We also conducted continuity adjusted chi-square, and McNemar tests in both the original and follow-up samples to measure the degree to which our results could be reproduced. Analyses were stratified by self-reported income.
The test-retest reliability was moderate for the majority of questions (0.41 - 0.60) and the level of test-retest reliability did not differ substantially across each of the broader domains of questions. The observed proportions of respondents with delayed or foregone pediatric, adult, or any family care were similar when comparing the original and follow-up surveys. In the original survey, respondents in the lower-income group were more likely to delay or forego pediatric care, adult care, or any family care. All of the tests comparing income groups in the follow-up survey produced the same result as in the original survey.
In this population of HDHP beneficiaries, we found that survey questions concerning plan knowledge, information seeking, and delayed or foregone care were moderately reliable. Our results offer reassurance for researchers using survey information to study the effects cost sharing on health care utilization.
Full-text · Article · May 2011 · BMC Health Services Research
[Show abstract][Hide abstract] ABSTRACT: Lower-income families may face unique challenges in high-deductible health plans (HDHPs).
We administered a cross-sectional survey to a stratified random sample of families in a New England health plan's HDHP with at least $500 in annualized out-of-pocket expenditures. Lower-income families were defined as having incomes that were less than 300% of the federal poverty level. Primary outcomes were cost-related delayed or foregone care, difficulty understanding plans, unexpected costs, information-seeking, and likelihood of families asking their physician about hypothetical recommended services subject to the plan deductible. Multivariate logistic regression was used to control for potential confounders of associations between income group and primary outcomes.
Lower-income families (n = 141) were more likely than higher-income families (n = 273) to report cost-related delayed or foregone care (57% vs 42%; adjusted odds ratio [AOR], 1.81; 95% confidence interval [CI], 1.15-2.83]). There were no differences in plan understanding, unexpected costs, or information-seeking by income. Lower-income families were more likely than others to say they would ask their physician about a $100 blood test (79% vs 63%; AOR, 1.97; 95% CI, 1.18-3.28) or a $1000 screening colonoscopy (89% vs 80%; AOR, 2.04; 95% CI, 1.06-3.93) subject to the plan deductible.
Lower-income families with out-of-pocket expenditures in an HDHP were more likely than higher-income families to report cost-related delayed or foregone care but did not report more difficulty understanding or using their plans, and might be more likely to question services requiring out-of-pocket expenditures. Policymakers and physicians should consider focused monitoring and benefit design modifications to support lower-income families in HDHPs.
Full-text · Article · Nov 2010 · Archives of internal medicine
[Show abstract][Hide abstract] ABSTRACT: To evaluate the effect of adverse events associated with live attenuated influenza vaccine (LAIV) in children younger than 5 years on the cost-effectiveness of influenza vaccination.
A decision analytic model was developed to predict costs and health effects of no vaccination, vaccination with LAIV, and vaccination with inactivated influenza vaccine (IIV). Probabilities, costs, and quality adjustments for uncomplicated influenza, outpatient visits, hospitalizations, deaths, vaccination, and vaccine adverse events were based on primary and published data. The analysis included the possible increased incidence of adverse events following vaccination with LAIV for children younger than 5 years, including fever, wheezing, and hospitalization. A societal perspective was used. Sensitivity analyses, including probabilistic sensitivity analysis, were conducted.
Vaccination in the physician office setting in the United States.
Hypothetical cohorts of healthy children aged 6 months to 4 years.
Vaccination with LAIV or IIV.
Incremental cost-effectiveness ratio in dollars per quality-adjusted life-year (QALY).
Cost-effectiveness ratios ranged from $20 000/QALY (age 6-23 months) to $33 000/QALY (age 3-4 years) for LAIV and from $21 000/QALY to $37 000/QALY for IIV for healthy children aged 6 months to 4 years. Inclusion of possible new adverse events for LAIV had varying effects on cost-effectiveness results. Results were not sensitive to the inclusion of wheezing as an adverse event but were sensitive to a possible increase in the probability of hospitalization.
Live attenuated influenza vaccine had comparable cost-effectiveness compared with IIV for children younger than 5 years under a wide range of assumptions about the incidence of adverse events.
[Show abstract][Hide abstract] ABSTRACT: Exposure to thimerosal, a mercury-containing preservative that is used in vaccines and immunoglobulin preparations, has been hypothesized to be associated with increased risk of autism spectrum disorder (ASD). This study was designed to examine relationships between prenatal and infant ethylmercury exposure from thimerosal-containing vaccines and/or immunoglobulin preparations and ASD and 2 ASD subcategories: autistic disorder (AD) and ASD with regression.
A case-control study was conducted in 3 managed care organizations (MCOs) of 256 children with ASD and 752 controls matched by birth year, gender, and MCO. ASD diagnoses were validated through standardized in-person evaluations. Exposure to thimerosal in vaccines and immunoglobulin preparations was determined from electronic immunization registries, medical charts, and parent interviews. Information on potential confounding factors was obtained from the interviews and medical charts. We used conditional logistic regression to assess associations between ASD, AD, and ASD with regression and exposure to ethylmercury during prenatal, birth-to-1 month, birth-to-7-month, and birth-to-20-month periods.
There were no findings of increased risk for any of the 3 ASD outcomes. The adjusted odds ratios (95% confidence intervals) for ASD associated with a 2-SD increase in ethylmercury exposure were 1.12 (0.83-1.51) for prenatal exposure, 0.88 (0.62-1.26) for exposure from birth to 1 month, 0.60 (0.36-0.99) for exposure from birth to 7 months, and 0.60 (0.32-0.97) for exposure from birth to 20 months.
In our study of MCO members, prenatal and early-life exposure to ethylmercury from thimerosal-containing vaccines and immunoglobulin preparations was not related to increased risk of ASDs.
[Show abstract][Hide abstract] ABSTRACT: Invasive pneumococcal disease (IPD) has been reduced in the US following conjugate vaccination (PCV7) targeting seven pneumococcal serotypes in 2000. However, increases in IPD due to other serotypes have been observed, in particular 19A. How much this "serotype replacement" will erode the benefits of vaccination and over what timescale is unknown. We used a population genetic approach to test first whether the selective impact of vaccination could be detected in a longitudinal carriage sample, and secondly how long it persisted for following introduction of vaccine in 2000. To detect the selective impact of the vaccine we compared the serotype diversity of samples from pneumococcal carriage in Massachusetts children collected in 2001, 2004 and 2007 with others collected in the pre-vaccine era in Massachusetts, the UK and Finland. The 2004 sample was significantly (p >0.0001) more diverse than pre-vaccine samples, indicating the selective pressure of vaccination. The 2007 sample showed no significant difference in diversity from the pre-vaccine period, and exhibited similar population structure, but with different serotypes. In 2007 the carriage frequency of 19A was similar to that of the most common serotype in pre-vaccine samples. We suggest that serotype replacement involving 19A may be complete in Massachusetts due to similarities in population structure to pre-vaccine samples. These results suggest that the replacement phenomenon occurs rapidly with high vaccine coverage, and may allay concerns about future increases in disease due to 19A. For other serotypes, the future course of replacement disease remains to be determined.
[Show abstract][Hide abstract] ABSTRACT: High-deductible health plans (HDHPs) are a new and controversial approach to increasing the share of health care costs paid by patients. Our study had the following aims: (1) to describe the experiences of families with HDHPs who had incurred high out-of-pocket costs and (2) to identify areas where clinicians could support more effective health care decisions by such families.
We conducted four focus groups with adults whose families had HDHPs in a New England-based health plan and had experienced high or unexpected out-of-pocket health care costs during the past 12 months. Transcripts of audio recordings were independently coded by three investigators using modified grounded theory techniques.
The 21 focus group participants had a good general understanding of how their HDHP worked, but reported confusion about specific processes due to the plans' complexity. They described heightened awareness of health care costs, and identified important barriers to their ability to control costs. These included needing to seek care for urgent problems without having the time to assess potential costs; having mistaken expectations about what services the HDHP covered; and being reluctant to discuss costs with doctors. They attempted to control costs by delaying or avoiding visits to doctors, but felt they had little control over costs once a clinical encounter had begun.
Patients with HDHPs reported heightened sensitivity to health care costs, and described important barriers to their ability to make effective choices. Helping such patients make optimal decisions will likely require systems-level changes that involve clinicians and health insurers.
Full-text · Article · Mar 2010 · Journal of General Internal Medicine
[Show abstract][Hide abstract] ABSTRACT: Studies of influenza vaccination using electronic medical records rely on accurate classification of vaccination status. Vaccinations not entered into electronic records would be unavailable for study.
This study evaluated the sensitivity and negative predictive value (NPV) of electronic records for influenza vaccination and factors associated with failure to capture vaccinations.
In four diverse medical care organizations in the Vaccine Safety Datalink, those aged 50-79 years with no influenza vaccination record during the 2007-2008 season were surveyed by telephone, and electronic records were analyzed in 2008. The sensitivity and NPV of electronic records were estimated, using survey responses as the gold standard. Logistic regression models determined associations between 1-NPV and demographic factors, risk of influenza complications, and healthcare utilization levels.
Data were obtained for 933 survey participants and 1,085,916 medical care organization members. Sites varied significantly in the sensitivity (51%, 68%, 79%, 89%) and NPV (46%, 62%, 66%, 87%) of electronic records. In multivariate analysis, the rate of failure to capture vaccinations was significantly higher for those aged 65-79 years than for those aged 50-64 years at three sites. Of vaccinations not captured by electronic records, 58% were reportedly administered in nontraditional settings, usually workplaces; the rest were given within the sites.
Influenza vaccination studies relying on electronic records may misclassify substantial proportions of vaccinated individuals as unvaccinated, producing biased estimates of vaccine effectiveness. Sites with limited sensitivity to capture vaccinations administered within their organization should seek possible remedies. More complete capture of vaccinations administered to older patients and in nontraditional settings would further reduce misclassification.
No preview · Article · Dec 2009 · American journal of preventive medicine
[Show abstract][Hide abstract] ABSTRACT: The goals were to assess serial changes in Streptococcus pneumoniae serotypes and antibiotic resistance in young children and to evaluate whether risk factors for carriage have been altered by heptavalent pneumococcal conjugate vaccine (PCV7).
Nasopharyngeal specimens and questionnaire/medical record data were obtained from children 3 months to <7 years of age in primary care practices in 16 Massachusetts communities during the winter seasons of 2000-2001 and 2003-2004 and in 8 communities in 2006-2007. Antimicrobial susceptibility testing and serotyping were performed with S pneumoniae isolates.
We collected 678, 988, and 972 specimens during the sampling periods in 2000-2001, 2003-2004, and 2006-2007, respectively. Carriage of non-PCV7 serotypes increased from 15% to 19% and 29% (P < .001), with vaccine serotypes decreasing to 3% of carried serotypes in 2006-2007. The relative contribution of several non-PCV7 serotypes, including 19A, 35B, and 23A, increased across sampling periods. By 2007, commonly carried serotypes included 19A (16%), 6A (12%), 15B/C (11%), 35B (9%), and 11A (8%), and high-prevalence serotypes seemed to have greater proportions of penicillin nonsusceptibility. In multivariate models, common predictors of pneumococcal carriage, such as child care attendance, upper respiratory tract infection, and the presence of young siblings, persisted.
The virtual disappearance of vaccine serotypes in S pneumoniae carriage has occurred in young children, with rapid replacement with penicillin-nonsusceptible nonvaccine serotypes, particularly 19A and 35B. Except for the age group at highest risk, previous predictors of carriage, such as child care attendance and the presence of young siblings, have not been changed by the vaccine.
[Show abstract][Hide abstract] ABSTRACT: The incidence of community-associated methicillin-resistant Staphylococcus aureus (MRSA) has risen dramatically in the U.S., particularly among children. Although Streptococcus pneumoniae colonization has been inversely associated with S. aureus colonization in unvaccinated children, this and other risk factors for S. aureus carriage have not been assessed following widespread use of the heptavalent pneumococcal conjugate vaccine (PCV7). Our objectives were to (1) determine the prevalence of S. aureus and MRSA colonization in young children in the context of widespread use of PCV7; and (2) examine risk factors for S. aureus colonization in the post-PCV7 era, including the absence of vaccine-type S. pneumoniae colonization.
Swabs of the anterior nares (S. aureus) were obtained from children enrolled in an ongoing study of nasopharyngeal pneumococcal colonization of healthy children in 8 Massachusetts communities. Children 3 months to <7 years of age seen for well child or sick visits in primary care offices from 11/03-4/04 and 10/06-4/07 were enrolled. S. aureus was identified and antibiotic susceptibility testing was performed. Epidemiologic risk factors for S. aureus colonization were collected from parent surveys and chart reviews, along with data on pneumococcal colonization. Multivariate mixed model analyses were performed to identify factors associated with S. aureus colonization.
Among 1,968 children, the mean age (SD) was 2.7 (1.8) years, 32% received an antibiotic in the past 2 months, 2% were colonized with PCV7 strains and 24% were colonized with non-PCV7 strains. The prevalence of S. aureus colonization remained stable between 2003-04 and 2006-07 (14.6% vs. 14.1%), while MRSA colonization remained low (0.2% vs. 0.9%, p = 0.09). Although absence of pneumococcal colonization was not significantly associated with S. aureus colonization, age (6-11 mo vs. > or =5 yrs, OR 0.39 [95% CI 0.24-0.64]; 1-1.99 yrs vs. > or =5 yrs, OR 0.35 [0.23-0.54]; 2-2.99 yrs vs. > or =5 yrs, OR 0.45 [0.28-0.73]; 3-3.99 yrs vs. > or =5 yrs, OR 0.53 [0.33-0.86]) and recent antibiotic use were significant predictors in multivariate models.
In Massachusetts, S. aureus and MRSA colonization remained stable from 2003-04 to 2006-07 among children <7 years despite widespread use of pneumococcal conjugate vaccine. S. aureus nasal colonization varies by age and is inversely correlated with recent antibiotic use.
[Show abstract][Hide abstract] ABSTRACT: New vaccines that offer protection against otitis media caused by nontypeable Haemophilus influenzae and by Moraxella catarrhalis are under development. However, the potential health benefits and economic effects of such candidate vaccines have not been systematically assessed.
We created a computerized model to compare the projected benefits and costs of (1) the currently available 7-valent pneumococcal conjugate vaccine, (2) a candidate pneumococcal-nontypeable H influenzae vaccine that has been tested in Europe, (3) a hypothetical pneumococcal-nontypeable H influenzae-Moraxella vaccine, and (4) no vaccination. The clinical probabilities of acute otitis media and of otitis media with effusion were generated from multivariate analyses of data from 2 large health maintenance organizations and from the Pittsburgh Child Development/Otitis Media Study cohort. Other probabilities, costs, and quality-of-life values were derived from published and unpublished sources. The base-case analysis assumed vaccine dose costs of $65 for the 7-valent pneumococcal conjugate vaccine, $100 for the pneumococcal-nontypeable H influenzae vaccine, and $125 for the pneumococcal-nontypeable H influenzae-Moraxella vaccine.
With no vaccination, we projected that 13.7 million episodes of acute otitis media would occur annually in US children aged 0 to 4 years, at an annual cost of $3.8 billion. The 7-valent pneumococcal conjugate vaccine was projected to prevent 878,000 acute otitis media episodes, or 6.4% of those that would occur with no vaccination; the corresponding value for the pneumococcal-nontypeable H influenzae vaccine was 3.7 million (27%) and for the pneumococcal-nontypeable H influenzae-Moraxella vaccine was 4.2 million (31%). Using the base-case vaccine costs, pneumococcal-nontypeable H influenzae vaccine use would result in net savings compared with nontypeable 7-valent pneumococcal conjugate use. Conversely, pneumococcal-nontypeable H influenzae-Moraxella vaccine use would not result in savings compared with pneumococcal-nontypeable H influenzae vaccine use, but would cost $48 000 more per quality-adjusted life-year saved. The results were sensitive to variations in assumptions on vaccine effectiveness and vaccine dose costs but not to variations in other assumptions.
New candidate vaccines against otitis media have the potential to prevent millions of disease episodes in the United States annually. If priced comparably with other recently introduced vaccines, these new otitis vaccines could achieve cost-effectiveness comparable with or more favorable than that of the 7-valent pneumococcal conjugate vaccine.
[Show abstract][Hide abstract] ABSTRACT: Spatial global clustering tests can be used to evaluate the geographical distribution of health outcomes. The power of several of these tests has been evaluated and compared using simulated data, but their performance using real unadjusted data and data adjusted for individual- and area-level covariates has not been reported previously.We evaluated data on prostate cancer histologic tumor grade and stage of disease at diagnosis for incident cases of prostate cancer reported to the Maryland Cancer Registry during 1992-1997. We analyzed unadjusted data as well as expected counts from models that were adjusted for individual-level covariates (race, age and year of diagnosis) and area-level covariates (census block group median household income and a county-level socioeconomic index). We chose 3 spatial clustering tests that are commonly used to evaluate the geographic distribution of disease: Cuzick-Edwards' k-NN (k-Nearest Neighbors) test, Moran's I and Tango's MEET (Maximized Excess Events Test).
For both grade and stage at diagnosis, we found that Cuzick-Edwards' k-NN and Moran's I were very sensitive to the percent of population parameter selected. For stage at diagnosis, all three tests showed that the models with individual- and area-level adjustments reduced clustering the most, but did not reduce it entirely.
Based on this specific example, results suggest that these tests provide useful tools for evaluating spatial clustering of disease characteristics, both before and after consideration of covariates.
Full-text · Article · Feb 2009 · International Journal of Health Geographics
[Show abstract][Hide abstract] ABSTRACT: Purpose: A recent randomized controlled trial among children <5 years of age found that live attenuated influenza vaccine (LAIV) was more effective in preventing laboratory-confirmed influenza compared to inactivated influenza vaccine (IIV). However, these new data suggest an increase in adverse events, such as wheezing, in children less than 5 years of age for LAIV compared to IIV. LAIV is now licensed for children 2 years or older without a history of wheezing or asthma. This study incorporated new data on adverse events into a validated model of the cost-effectiveness of influenza vaccination in children.
Methods: A decision tree was developed to predict the costs and health effects of no vaccination, vaccination with IIV, and vaccination with LAIV for healthy children aged 6-23 months, 2 years, and 3-4 years. Probabilities, costs (direct and opportunity), and quality adjustments for uncomplicated influenza, outpatient visits, hospitalizations, deaths, vaccination and vaccine adverse events were based on primary and published data. The model included the possible increased incidence of adverse events following vaccination for LAIV, including fever, wheezing, and hospitalization. Cohorts of 1,000 children were considered separately for each age group. The primary endpoint was the incremental cost-effectiveness ratio. Sensitivity analyses, including a probabilistic sensitivity analysis, were conducted. A societal perspective was used. The analysis used a time horizon of one year and also included losses beyond one year associated with long-term sequelae (discounted at 3% per annum).
Results: Cost-effectiveness ratios ranged from $20,000/QALY (6-23 months) to $33,000/QALY (3-4 years) for LAIV and from $21,000-$37,000 for IIV. Inclusion of possible new adverse events for LAIV had varying effects on cost-effectiveness results. Results were not sensitive to the inclusion of wheezing as an adverse event but were very sensitive to including a possible increased probability of hospitalization. Overall, cost-effectiveness ratios increased by 5-10%, depending on age, with the inclusion of wheezing-related adverse events.
Conclusions: LAIV had cost-effectiveness ratios within the same range as other recently recommended vaccines. It remained more effective than IIV for children younger than 5 years under a wide range of assumptions about adverse event rates. The results were sensitive to an increase in the probability of hospitalization at the highest rates evaluated; post-licensing safety studies of both live and inactivated influenza vaccines in children should continue.
[Show abstract][Hide abstract] ABSTRACT: It has been hypothesized that early exposure to thimerosal, a mercury-containing preservative used in vaccines and immune globulin preparations, is associated with neuropsychological deficits in children.
We enrolled 1047 children between the ages of 7 and 10 years and administered standardized tests assessing 42 neuropsychological outcomes. (We did not assess autism-spectrum disorders.) Exposure to mercury from thimerosal was determined from computerized immunization records, medical records, personal immunization records, and parent interviews. Information on potential confounding factors was obtained from the interviews and medical charts. We assessed the association between current neuropsychological performance and exposure to mercury during the prenatal period, the neonatal period (birth to 28 days), and the first 7 months of life.
Among the 42 neuropsychological outcomes, we detected only a few significant associations with exposure to mercury from thimerosal. The detected associations were small and almost equally divided between positive and negative effects. Higher prenatal mercury exposure was associated with better performance on one measure of language and poorer performance on one measure of attention and executive functioning. Increasing levels of mercury exposure from birth to 7 months were associated with better performance on one measure of fine motor coordination and on one measure of attention and executive functioning. Increasing mercury exposure from birth to 28 days was associated with poorer performance on one measure of speech articulation and better performance on one measure of fine motor coordination.
Our study does not support a causal association between early exposure to mercury from thimerosal-containing vaccines and immune globulins and deficits in neuropsychological functioning at the age of 7 to 10 years.
Full-text · Article · Oct 2007 · New England Journal of Medicine
[Show abstract][Hide abstract] ABSTRACT: We implemented an automated vaccine adverse event surveillance and reporting system based in an ambulatory electronic medical record to improve underreporting and incomplete reporting that prevails in spontaneous systems. This automated system flags potential vaccine adverse events for the clinician when a diagnosis is entered, prompts clinicians to consider the vaccine as a cause of the condition, and facilitates reporting of suspected adverse events to the Vaccine Adverse Event Reporting System (VAERS). During five months, a total of 33,420 vaccinations were administered during 14,466 encounters. There were 5,914 follow-up contacts by vaccinees within 14 days of the vaccination visits; 686 (11.6%) generated an alert. Clinicians submitted VAERS reports for 23 of these (0.69 per 1,000 vaccine doses), which is almost 6 times the dose-based reporting rate to VAERS. (1) Clinician surveys indicated that it took a minimal amount of time to respond to the alerts. Of those who felt that an alert corresponded to an actual vaccine adverse event, the majority used the reporting feature to file a VAERS report. We believe that elicited surveillance via real time prompts to clinicians holds substantial promise. By coupling simplified reporting with the initial prompt, clinicians can consider and report a vaccine adverse event electronically in a few moments during the office visit.
Full-text · Article · Aug 2007 · Journal of the American Medical Informatics Association
[Show abstract][Hide abstract] ABSTRACT: As infection with vancomycin-resistant enterococci (VRE) increases in hospitals, knowledge about VRE reservoirs and improved accuracy of epidemiologic measures are needed. Many assessments underestimate incidence by including prevalent carriers in at-risk populations. Routine surveillance cultures can substantially improve prevalence and incidence estimates, and assessing the range of improvement across diverse units is important.
We performed a retrospective cohort study using accurate at-risk populations to evaluate the range of benefit of admission and weekly surveillance cultures in detecting unrecognized VRE in 14 patient-care units.
We assessed 165 unit-months. The admission prevalence of VRE was 2.2%-27.2%, with admission surveillance providing 2.2-17-fold increased detection. Medical units were significantly more likely to admit VRE carriers than were surgical units. Monthly incidence was 0.8%-9.7%, with weekly surveillance providing 3.3-15.4-fold increased detection. The common practice of reporting incidence using the total number of patients, rather than patients at risk, underestimated incidence by one-third. Overall, routine surveillance prevented the misclassification of 43.0% (unit range, 0%-85.7%) of "incident" carriers on the basis of clinical cultures alone and increased VRE precaution days by 2.4-fold (unit range, 2.0-2.6-fold).
Routine surveillance markedly increases the detection of VRE, despite variability across patient-care units. Correct denominators prevent the substantial underestimation of incidence.
Full-text · Article · Mar 2007 · The Journal of Infectious Diseases
[Show abstract][Hide abstract] ABSTRACT: Routine culturing of patients in intensive care units (ICUs) for methicillin-resistant Staphylococcus aureus (MRSA) identifies unrecognized carriers and facilitates timely isolation. However, the benefit of surveillance in detecting prevalent and incident carriers likely varies among ICUs. In addition, many assessments underestimate the incidence of acquisition by including prevalent carriers in the at-risk population.
We performed a retrospective cohort study using accurate at-risk populations to evaluate the range of benefit of admission and weekly surveillance cultures in detecting otherwise unrecognized MRSA in 12 ICUs in 5 states.
We assessed 142 ICU-months. Among the 12 ICUs, the admission prevalence of imported MRSA was 5%-21%, with admission surveillance providing 30%-135% increases in rates of detection. The monthly hospital-associated incidence was 2%-6%, with weekly surveillance providing 7%-157% increases in detection. The common practice of reporting incidence using the total number of patients or total patient-days underestimated incidence by one-third. Surgical ICUs had lower MRSA importation but higher MRSA incidence. Overall, routine surveillance prevented the misclassification of 17% (unit range, 11%-29%) of "incident" carriers, compared with clinical cultures, and increased precaution days by 18% (unit range, 11%-91%).
Routine surveillance significantly increases the detection of MRSA, but this benefit is not uniform across ICUs, even with high compliance and the use of correct denominators.
No preview · Article · Mar 2007 · The Journal of Infectious Diseases