Biomedical subjects

Charles W LeBaron

Publications and source records attributed to Charles W LeBaron.

12 recordsLinked to original sources

PubMed2006

Implications of a 2005 measles outbreak in Indiana for sustained elimination of measles in the United States.

BACKGROUND: Measles was declared eliminated from the United States in 2000 but remains endemic worldwide. In 2005, a 17-year-old unvaccinated girl who was incubating measles returned from Romania, creating the largest documented outbreak of measles in the United States since 1996. METHODS: We conducted a case-series investigation, molecular typing of viral isolates, surveys of rates of vaccination coverage, interviews regarding attitudes toward vaccination, and cost surveys. RESULTS: Approximately 500 persons attended a gathering with the index patient one day after her return home. Approximately 50 lacked evidence of measles immunity, of whom 16 (32 percent) acquired measles at the gathering. During the six weeks after the gathering, a total of 34 cases of measles were confirmed. Of the patients with confirmed measles, 94 percent were unvaccinated, 88 percent were less than 20 years of age, and 9 percent were hospitalized. Of the 28 patients who were 5 to 19 years of age, 71 percent were home-schooled. Vaccine failure occurred in two persons. The virus strain was genotype D4, which is endemic in Romania. Although containment measures began after 20 persons were already infectious, measles remained confined mostly to children whose parents had refused to have them vaccinated, primarily out of concern for adverse events from the vaccine. Seventy-one percent of patients were from four households. Levels of measles-vaccination coverage in Indiana were 92 percent for preschoolers and 98 percent for sixth graders. Estimated costs of containing the disease were at least 167,685 dollars, including 113,647 dollars at a hospital with an infected employee. CONCLUSIONS: This outbreak was caused by the importation of measles into a population of children whose parents had refused to have them vaccinated because of safety concerns about the vaccine. High vaccination levels in the surrounding community and low rates of vaccine failure averted an epidemic. Maintenance of high rates of vaccination coverage, including improved strategies of communication with persons who refuse vaccination, is necessary to prevent future outbreaks and sustain the elimination of measles in the United States.

Adolescent↗

PubMed2006

Evaluation of potentially common adverse events associated with the first and second doses of measles-mumps-rubella vaccine.

BACKGROUND/OBJECTIVES: In 1989, the American Academy of Pediatrics and the Advisory Committee on Immunization Practices recommended that school children receive 2 doses of measles-mumps-rubella vaccine. With measles and rubella eliminated from the United States, measles-mumps-rubella vaccine adverse events have come under scrutiny, but no study has compared the reactogenicity of the first (measles-mumps-rubella vaccine dose 1) and second (measles-mumps-rubella vaccine dose 2) doses at the most common ages of administration in the United States. METHODS: From a health maintenance organization, 3 groups of children were recruited: (1) toddlers aged 12 to 24 months receiving measles-mumps-rubella vaccine dose 1; (2) kindergartners aged 4 to 6 years receiving measles-mumps-rubella vaccine dose 2; and (3) middle schoolers aged 10 to 12 years receiving measles-mumps-rubella vaccine dose 2. From 2 weeks before measles-mumps-rubella vaccine administration until 4 weeks afterward, families recorded in diaries the occurrence of potentially common symptoms. Postvaccination symptom rates were compared with the prevaccination baseline, with significance assessed by testing incidence rate ratios estimated by Poisson regression. RESULTS: Of 2173 children enrolled, 373 (17%) were lost to attrition, producing a study population of 1800. Compared with the prevaccination baseline, rates of fever, diarrhea, and rash were significantly elevated postvaccination among 535 toddlers receiving measles-mumps-rubella vaccine dose 1. An estimated net 95 (18%) experienced measles-mumps-rubella vaccine-associated events (median onset 5-10 days postvaccination, duration 2-5 days), with high fever (temperature > or = 39.5 degrees C) occurring in 33 (6%). None required medical attention. For 633 kindergartners and 632 middle schoolers, symptom rates were not significantly elevated after measles-mumps-rubella vaccine dose 2 compared with baseline. CONCLUSIONS: Vaccination-associated adverse events occur in approximately 1 of every 6 toddlers receiving measles-mumps-rubella vaccine dose 1, with high fever occurring in 1 of 20. Adverse events are infrequent for measles-mumps-rubella vaccine dose 2 administered to school-aged children.

Age Factors↗

PubMed2005

Measles transmission and vaccine effectiveness during a large outbreak on a densely populated island: implications for vaccination policy.

BACKGROUND: The Republic of the Marshall Islands (RMI) is a South Pacific nation freely associated with the United States. In 2003, the RMI experienced the largest measles outbreak within the United States or its associated areas for more than a decade, although the reported coverage of 1-dose measles-mumps-rubella (MMR) vaccine was 80%-93%. The outbreak ended only after vaccination of >35,000 persons among a population of 51,000. Of outbreak cases, 41% were reported to have been previously vaccinated. We studied measles attack rates in RMI households to assess vaccine effectiveness and patterns of disease transmission. METHODS: For the household secondary attack rate study, households were selected by convenience sampling of outbreak measles cases. The primary case was defined as the first person with measles in a household. Secondary cases were household members with measles onset 7-18 days after the primary case's rash onset. Vaccine effectiveness analysis was limited to children aged 6 months to 14 years, with vaccination status verified against written records. RESULTS: Seventy-two households were included in the study. The median household size was 11 persons, and the median number of persons per room was 5.5. Secondary cases were more likely than primary cases to be infants (46% vs. 13%; P=.03). MMR vaccine effectiveness was 92% (95% confidence interval [CI], 67%-98%) for 1 dose and 95% (95% CI, 82%-98%) for 2 doses. CONCLUSIONS: Measles vaccine effectiveness was high; thus, diminished effectiveness was not the main cause of the outbreak. In communities with high population density and household crowding, very high population immunity is needed to prevent measles outbreaks and to protect infants below the age of vaccination. This may require excellent implementation of a routine 2-dose measles vaccination strategy.

Adolescent↗

PubMed2005

Health-state valuations for pertussis: methods for valuing short-term health states.

BACKGROUND: The incidence of reported adolescent and adult pertussis continues to rise in the United States. Acellular pertussis vaccines for adolescents and adults have been developed and may be available soon for use in the U.S. Our objectives were: (1) to describe patient valuations of pertussis disease and vaccination; and (2) to compare valuations for short-term and long-term health states associated with pertussis. METHODS: We conducted telephone surveys with 515 adult patients and parents of adolescent patients with pertussis in Massachusetts to determine valuations of pertussis-related health states for disease and vaccination using time trade-off (TTO) and contingent valuation (CV) techniques. Respondents were randomized to complete either a short-term or long-term TTO exercise. Discrimination between health states for each valuation technique was assessed using Tukey's method, and valuations for short-term vs. long-term health states were compared using the Wilcoxon rank-sum test. RESULTS: Three hundred three (59%) and 309 (60%) respondents completed and understood the TTO and CV exercises, respectively. Overall, respondents gave lower valuations (lower TTO and higher CV values) to avoid a given state for adolescent/adult disease compared to vaccine adverse events. Infant complications due to pertussis were considered worse than adolescent/adult disease, regardless of the method of valuation. The short-term TTO resulted in lower mean valuations and larger mean differences between health states than the long-term TTO exercise. CONCLUSION: Pertussis was considered worse than adverse events due to vaccination. Short-term health-state valuation is better able to discriminate among health states, which is useful for cost-utility analysis.

Acute Disease↗

PubMed2005

The cost of containing one case of measles: the economic impact on the public health infrastructure--Iowa, 2004.

BACKGROUND: In February 2004, students from a college in Iowa, with a high proportion of nonmedical exemptions to vaccination, traveled to India; one fourth of the students contracted measles while there. One exposed, susceptible student returned home during his infectious period, necessitating 2 months of containment efforts in Iowa. OBJECTIVE: The objective of this study was to measure the direct costs of measles containment from a public health system perspective. METHODS: We evaluated activities performed, personnel time/materials allocated, and direct costs incurred in 2004 US dollars by the Iowa public health infrastructure. The study period was defined as March 5, 2004 (when the Iowa Department of Public Health was first contacted about the case), through May 12, 2004 (when a final meeting was held on the containment effort). RESULTS: A total of 2525 hours of personnel time were expended to review flight manifests, contact exposed passengers, set up vaccination clinics, trace >1000 potentially exposed contacts, and institute and enforce quarantine orders for vaccination refusers. Two thousand twenty-five phone calls were received from the public, and 2243 miles were driven by staff. The temporal distribution of personnel time was characterized by marked peaks at the report of potential secondary cases. The total estimated cost was 142452 dollars. CONCLUSIONS: The direct cost to the public health infrastructure of containing 1 case of measles was far greater than the estimated cost of uncomplicated individual illness (less than 100 dollars). Economic analyses of vaccine-preventable diseases may need to go beyond the costs of individual illness to account for the costs of protecting society.

Contact Tracing↗

PubMed2004

Ensuring preparedness for potential poliomyelitis outbreaks: Recommendations for the US poliovirus vaccine stockpile from the National Vaccine Advisory Committee (NVAC) and the Advisory Committee on Immunization Practices (ACIP).

Paralytic poliomyelitis was once endemic in the United States; however, because of high vaccination levels, the last case of wild disease occurred in 1979. Although worldwide polio eradication may be achieved in the near future, the presence of undervaccinated children in urban areas and among groups who refuse vaccination creates an outbreak risk, should importation of wild virus occur. In 1999, the Advisory Committee on Immunization Practices (ACIP) recommended that inactivated poliovirus vaccine (IPV) be used for routine immunization of the US population and that oral poliovirus vaccine (OPV) be reserved for "mass vaccination campaigns to control outbreaks of paralytic polio." Subsequently, the sole US manufacturer of OPV withdrew from the market. In 2003, a joint National Vaccine Advisory Committee (NVAC)/ACIP working group was charged with reporting to its parent bodies concerning the need for a poliovirus vaccine stockpile. Based on that working group's report, the NVAC and ACIP have concluded that stockpiles of both IPV and OPV should be maintained. In the event of an outbreak in which OPV continues not to be available, IPV should be used for control, and a stockpile of 8 million doses seems to be sufficient. Should IPV be manufactured only in combination with other vaccines, appropriate procurement actions should be taken to ensure that uncombined IPV continues to be stockpiled. Under circumstances of diminished population immunity, OPV may offer outbreak control advantages. The NVAC and ACIP recommend that the United States collaborate with international agencies to provide guaranteed and rapid access to at least 8 million doses of trivalent OPV or 8 million doses of each of the 3 types of monovalent OPV. The regulatory and practical obstacles to implementation of this recommendation will require assertive facilitation at high levels of the federal government and careful planning at the state and local levels.

Bioterrorism↗

PubMed2004

Strategies to improve immunization rates and well-child care in a disadvantaged population: a cluster randomized controlled trial.

OBJECTIVE: To measure the effect of a multimodal intervention on well-child care visit (WCV) and immunization rates in an inner-city population. DESIGN: Cluster randomized controlled trial. SETTING AND PARTICIPANTS: One-year cohort of 2843 infants born at a hospital in an integrated inner-city health care system. INTERVENTIONS: Eleven clinics were randomly allocated to 1 of 3 study arms: WCV intervention (n = 3), immunization intervention (n = 4), and controls (n = 4). Interventions to improve immunization and WCV rates included both patient-based and clinic-based activities. MAIN OUTCOME MEASURES: Up-to-date status with childhood immunizations and WCVs by age 12 months (primary) and health care utilization and charges (secondary). RESULTS: Compared with the control arm, the WCV and immunization arms had 5% to 6% higher immunization rates and 7% to 8% higher WCV rates. In multivariate analyses that accounted for the clustered nature of the data, the number of immunizations received was greater in the WCV arm than in controls. However, neither the WCV nor the immunization intervention increased WCV or immunization up-to-date rates. The WCV arm had slightly higher health care charges. Neither intervention affected emergency, urgent care or inpatient utilization. CONCLUSIONS: This multimodal intervention produced a small increase in the number of childhood immunizations delivered. However, patient- and clinic-based methods did not lead to significant increases in WCV or immunization up-to-date rates after controlling for other factors. Methods found in some settings to increase immunization up-to-date rates may not be as effective in a population of inner-city socioeconomically disadvantaged children.

Child Health Services↗

PubMed2004

The impact of reminder-recall interventions on low vaccination coverage in an inner-city population.

BACKGROUND: Reminder-recall interventions have improved immunization rates in numerous studies. OBJECTIVE: To evaluate the impact of large-scale, registry-based reminder-recall interventions on low immunization rates in an inner-city population. DESIGN: Randomized, controlled, effectiveness trial. SETTING: Fulton County, Georgia. PARTICIPANTS: A total of 3050 children (76% black, 14% Hispanic, 7% white, and 3% other or unknown; median age, 9 months; range, 1-14 months) identified in an immunization registry as receiving health care in the public sector. INTERVENTIONS: Each child was randomly assigned to 1 of 4 groups: control (usual care), autodialer (automated telephone or mail reminder recall), outreach (in-person telephone, mail, or home visit recall), and combination (autodialer with outreach backup). Interventions continued until the child reached 24 months of age. MAIN OUTCOME MEASURE: Completion by the age of 24 months of the 4-3-1-3 vaccination series based on intention-to-treat analysis. RESULTS: A total of 260 (34%) of the 763 patients in the control group, 306 (40%) of the 763 in the autodialer group, 284 (37%) of the 760 in the outreach group, and 293 (38%) of 764 in the combination group completed the vaccination series. CONCLUSION: Large-scale, registry-based reminder-recall interventions produced only small improvements in low immunization rates of an inner-city population.

Female↗

PubMed2003

Immunization registry accuracy: improvement with progressive clinical application.

BACKGROUND: Healthcare systems have been challenged to ensure the timely administration of immunizations. Immunization registries have been proposed to improve the accuracy and completeness of immunization information and to promote effective practice. METHODS: Comparison of randomly selected samples from two birth cohorts (1993 and 1998) from Denver Health Medical Center. Chart review and immunization registry information for these groups were compared; a composite immunization was recorded and up-to-date (UTD) status established. Registry data were compared with this composite using a sensitivity measure to assess completeness and accuracy. RESULTS: Among 818 children in the 1993 cohort and 1043 children in the 1998 cohort, there were 6386 and 6886 valid immunizations, respectively. The registry recorded 71.4% and 97.7% of these for the 1993 and 1998 cohorts, respectively (p <0.001). The apparent UTD rate, as measured with registry data alone, improved from 37% to 79% between the two time frames (p <0.001). Composite UTD status was 83.1% and 78.9% (1993 vs 1998, respectively). Accurate registry-defined UTD status improved from 44.4% to 100% between the two intervals. CONCLUSIONS: Immunization registry accuracy improved dramatically for recorded immunizations and UTD status. However, after 3 years of registry use, the overall proportion of children who were UTD had not significantly improved. The mere presence of a registry does not ensure more complete vaccination coverage. Other registry-based strategies, including use of the data for reminder, recall, and audit, may further improve immunization coverage.

Child↗

PubMed2002

Rotavirus vaccine and the news media, 1987-2001.

CONTEXT: In August 1998, the US Food and Drug Administration licensed the first vaccine against rotavirus, the most important cause of severe childhood diarrhea. Fourteen months later, amid intense media activity, the vaccine was withdrawn after an association was found with intussusception. OBJECTIVES: To examine the character of news media stories about rotavirus vaccine before and after intussusception became an issue, to evaluate what prompted the stories, and to assess the extent to which they evoked public reaction. DESIGN AND SETTING: We searched Lexis-Nexis and Video Monitoring Services of America databases for rotavirus vaccine stories from the first US clinical trials (January 1, 1987) until 17 months after withdrawal (March 31, 2001) and examined calls to the National Immunization Hotline during the period in which rotavirus vaccine information was captured (July 1-December 31, 1999). MAIN OUTCOME MEASURES: Mention of vaccine benefits and adverse events, classification of stories as positive, negative, or neutral toward the vaccine, story stimuli, and public response. RESULTS: We included 280 newspaper (primary subject of analysis), 49 wire service, and 257 television stories. Prior to identification of the intussusception association (January 1, 1987-July 14, 1999), 21% of 188 newspaper stories mentioned vaccine adverse events and only 2 stories were negative toward the vaccine. Ninety-nine percent of stories mentioned vaccine benefits. During the period surrounding withdrawal (July 15-December 31, 1999), 93% of 90 stories mentioned adverse events and 77% were negative toward the vaccine. Eighty-four percent mentioned vaccine benefits. The rate of stories per month was 14-fold greater than the preceding period (P<.001); temporal and geographic patterns of media and hotline activity were similar. Thereafter (January 1, 2000-March 31, 2001), only 2 stories focused on rotavirus vaccine. Scientific research or public health actions prompted 80% of stories. Wire service and television stories showed similar patterns. The increase in rotavirus stories in July 1999 was followed by an increase in calls to the National Immunization Hotline regarding rotavirus but not other topics. The number of rotavirus calls that month was 57% higher than for any other childhood vaccine for any month since the hotline began in 1997. Rotavirus calls ceased almost completely after withdrawal of the vaccine in October 1999. CONCLUSIONS: In response to reports about an adverse event, news media stories about vaccines can change abruptly from positivity to negativity. Since most vaccine stories may be stimulated by research and public health actions, opportunities exist to provide the media with accurate information necessary to avoid the "early idealization-sudden condemnation" pattern seen with rotavirus vaccine.

Hotlines↗

PubMed2002

Childhood vaccination providers in the United States.

OBJECTIVES: This study sought to provide a characterization of US childhood vaccination providers. METHODS: The state was used as the analytic unit in examining 1997 data from the National Immunization Survey and the Vaccines for Children program, state immunization reports, and natality records. RESULTS: Overall, 57% of children were vaccinated in the private sector, 18% were vaccinated in the public sector, and 25% were vaccinated by a mixture of providers. Of the 50 883 immunization sites, 81% were private and 19% public. Average patient load was 77 infants per site. Private-sector patient loads were lower than public-sector loads. CONCLUSIONS: US childhood vaccination provider capacity is adequate. Efforts to raise coverage rates should focus on increasing preventive care use among children, improving the vaccination performance of providers, and ensuring continuity of care.

Child↗

PubMedDate not supplied

Primary-care visits and hospitalizations for ambulatory-care-sensitive conditions in an inner-city health care system.

OBJECTIVE: Hospitalizations for ambulatory-care-sensitive conditions (ACSCs) are a marker for access barriers for children and a possible outcome measure for primary-care interventions. We assessed the relationship between primary-care utilization and subsequent ACSC hospitalization among inner-city children. METHODOLOGY: We conducted a nested, case-control study of children born in 1993 in Denver Health (DH), a "safety-net" delivery system in Denver, Colo. Utilization of preventive care and other primary-care services was compared between children hospitalized for ACSCs and nonhospitalized children, who were matched by age and duration of care. Comparisons were adjusted for demographics, payer, and chronic health conditions. RESULTS: Of 2531 children, 115 (4.5%) were hospitalized for ACSCs. Sixty-eight percent were Hispanic, and 78% were enrolled in Medicaid. Children with ACSC hospitalization and nonhospitalized children made a similar number of preventive-care visits (2.7 +/- 2.0 vs 3.0 +/- 2.1 visits, P =.30) and other primary-care visits (4.4 +/- 4.6 vs 3.6 +/- 4.6, P =.16) between birth and hospitalization (for cases) or the same time period (for controls). After multivariate adjustment, each additional preventive-care visit (odds ratio = 0.87; 95% confidence interval: 0.67-1.12) was associated with a nonsignificant reduction in the risk of hospitalization for ACSC. CONCLUSIONS: Because ACSC hospitalizations are uncommon and the association between primary care and subsequent hospitalization is weak, a reduction in ACSC hospitalizations may not be a feasible outcome measure for interventions to increase the rate of preventive- or primary-care visits for underserved children within individual delivery systems.

Ambulatory Care↗