C. D. C. Christie

The 1993 Epidemic of Pertussis in Cincinnati -- Resurgence of Disease in a Highly Immunized Population of Children

Background In 1993 there was a resurgence of pertussis in the United States. Altogether, 6335 cases were reported, the most in 26 years. Methods Using active microbiologic surveillance, we investigated the epidemic of pertussis in Greater Cincinnati in 1993. The population of 1.7 million in this area is served by a single childrens hospital and pertussis laboratory. We prospectively followed patients given a new diagnosis of pertussis in July through September 1993 to determine the characteristics of the epidemic. Results From 1979 to 1992, there was a cumulative total of 542 cases of pertussis. In 1993, 352 cases were diagnosed, an increase of 259 percent over the 1992 total. Sixty-three percent of the cases had positive cultures for Bordetella pertussis, 18 percent were positive on direct fluorescent-antibody testing only, and 19 percent were diagnosed clinically. The outbreak began in the suburbs during the summer and spread through Greater Cincinnati. Of 255 total cases diagnosed in July through Sept...

Efficacy of a pentavalent rotavirus vaccine in reducing rotavirus-associated health care utilization across three regions (11 countries)

OBJECTIVE To evaluate the effect of a human-bovine reassortant pentavalent rotavirus vaccine (PRV) on health care encounters in nearly 70 000 subjects randomized in three regions - Europe, the United States, and Latin America/the Caribbean - in the Rotavirus Efficacy and Safety Trial (REST). METHODS Healthy 6- to 12-week-old infants received 3 doses of PRV or placebo at 4- to 10-week intervals. The exact binomial method for ratios of Poisson counts was used to evaluate the effect of PRV on the rate of rotavirus-related hospitalizations and emergency department (ED) visits involving rotavirus G-types 1-4 occurring > or =14 days after the third dose of vaccine for up to 2 years. RESULTS In fully vaccinated infants, reductions in rotavirus-associated hospitalizations and ED visits were 94.7% (95% CI: 90.9, 96.9) in Europe, 94.9% (95% CI: 84.0, 98.9) in the United States, and 90.0% (95% CI: 29.4, 99.8) in the Latin American/Caribbean regions. CONCLUSIONS PRV reduced hospitalizations and ED visits within each region in REST. Results were consistent across regions and across the overall study cohort.

Student evaluation of an OSCE in paediatrics at the University of the West Indies, Jamaica

BackgroundThe Faculty of Medical Sciences, University of the West Indies first implemented the Objective Structured Clinical Examination (OSCE) in the final MB Examination in Medicine and Therapeutics during the 2000–2001 academic year. Simultaneously, the Child Health Department initiated faculty and student training, and instituted the OSCE as an assessment instrument during the Child Health (Paediatric) clerkship in year 5. The study set out to explore student acceptance of the OSCE as part of an evaluation of the Child Health clerkship.MethodsA self-administered questionnaire was completed by successive groups of students immediately after the OSCE at the end of each clerkship rotation. Main outcome measures were student perception of examination attributes, which included the quality of instructions and organisation, the quality of performance, authenticity and transparency of the process, and usefulness of the OSCE as an assessment instrument compared to other formats.ResultsThere was overwhelming acceptance of the OSCE in Child Health with respect to the comprehensiveness (90%), transparency (87%), fairness (70%) and authenticity of the required tasks (58–78%). However, students felt that it was a strong anxiety-producing experience. And concerns were expressed regarding the ambiguity of some questions and inadequacy of time for expected tasks.ConclusionStudent feedback was invaluable in influencing faculty teaching, curriculum direction and appreciation of student opinion. Further psychometric evaluation will strengthen the development of the OSCE.

Complicated parapneumonic effusions in children caused by penicillin-nonsusceptible Streptococcus pneumoniae

Objective. To describe the clinical characteristics of complicated parapneumonic effusions (CPE) in children caused by Streptococcus pneumoniae nonsusceptible to penicillin (PCN-N) and compare their clinical outcome with CPE caused by penicillin-susceptible (PCN-S) organisms. Design. Children with parapneumonic effusions were identified retrospectively between July 1992 and June 1996. Charts of patients with CPE were reviewed for data obtained at the time of hospital admission. In addition, outpatient charts and/or the families of children with CPE caused by PCN-N S pneumoniae were reviewed to identify specific risk factors associated with PCN-N organisms. Results. Sixty-four cases of CPE were identified during the 4-year period. In 26 cases a bacterial pathogen was recovered, withS pneumoniae accounting for 23 of these isolates (88%). Of the 23 S pneumoniae cases, 17 were PCN-S and 6 cases were nonsusceptible. Complicated parapneumonic effusions caused by PCN-NS pneumoniae occurred in significantly younger patients than CPE that were PCN-S (2.1 years vs 7.9 years). Nonsusceptible effusions also had a higher incidence of bacteremia than PCN-S effusions (100% vs 29%). There were no significant differences between the two groups for duration of chest tube drainage, febrile days, oxygen use, and hospital stay. Conclusion. CPE caused by PCN-N S pneumoniaeis associated with a younger age and higher rate of bacteremia than CPE caused by PCN-S strains. However, there were no significant differences in outcome measures between patients infected with susceptible or nonsusceptible organisms.

Molecular epidemiology of Bordetella pertussis by pulsed-field gel electrophoresis profile : Cincinnati, 1989-1996

Reported cases of pertussis have increased in the United States, with peaks occurring every few years. Bordetella pertussis isolates collected in Cincinnati from 1989 to 1996 were analyzed with pulsed-field gel electrophoresis (PFGE), to evaluate trends. Among 496 isolates, 30 PFGE profiles were identified; 32% were CYXXI-010, the profile that predominated each year. Eighteen profiles (198 strains) were identified in 1989-1992, 20 profiles (197 strains) were identified during the 1993 epidemic, and 11 profiles (101 strains) were identified in 1994-1996. From 1989 to 1996, among 42 patients, isolates from household members in 17 (89%) of 19 households had concordant PFGE profiles. There was no association between PFGE profile and seasonality, age, and hospitalization or pneumonia in infants <1 year old. The 1993 epidemic was associated primarily with an increased prevalence of PFGE profiles that circulated before and after 1993, which suggests that the epidemic was due to factors other than the emergence of a novel B. pertussis strain.

Deficiency of HIV-Gag-Specific T Cells in Early Childhood Correlates with Poor Viral Containment

Perinatal HIV infection is characterized by a sustained high-level viremia and a high risk of rapid progression to AIDS, indicating a failure of immunologic containment of the virus. We hypothesized that age-related differences in the specificity or function of HIV-specific T cells may influence HIV RNA levels and clinical outcome following perinatal infection. In this study, we defined the HIV epitopes targeted by 76 pediatric subjects (47 HIV infected and 29 HIV exposed, but uninfected), and assessed the ability of HIV-specific CD8 and CD4 T cells to degranulate and produce IFN-γ, TNF-α, and IL-2. No responses were detected among HIV-uninfected infants, whereas responses among infected subjects increased in magnitude and breadth with age. Gag-specific responses were uncommon during early infancy, and their frequency was significantly lower among children younger than 24 mo old (p = 0.014). Importantly, Gag responders exhibited significantly lower HIV RNA levels than nonresponders (log viral load 5.8 vs 5.0; p = 0.005). Both the total and Gag-specific T cell frequency correlated inversely with viral load after correction for age, whereas no relationship with targeting of other viral proteins was observed. Functional assessment of HIV-specific T cells by multiparameter flow cytometry revealed that polyfunctional CD8 cells were less prevalent in children before 24 mo of age, and that HIV-specific CD4 cell responses were of universally low frequency among antiretroviral-naive children and absent in young infants. These cross-sectional data suggest that qualitative differences in the CD8 response, combined with a deficiency of HIV-specific CD4 cells, may contribute to the inability of young infants to limit replication of HIV.

Lower respiratory tract infections among human immunodeficiency virus-exposed, uninfected infants

OBJECTIVES To evaluate whether maternal HIV disease severity during pregnancy is associated with an increased likelihood of lower respiratory tract infections (LRTIs) in HIV-exposed, uninfected infants. METHODS HIV-exposed, uninfected, singleton, term infants enrolled in the NISDI Perinatal Study, with birth weight >2500g were followed from birth until 6 months of age. LRTI diagnoses, hospitalizations, and associated factors were assessed. RESULTS Of 547 infants, 103 (18.8%) experienced 116 episodes of LRTI (incidence=0.84 LRTIs/100 child-weeks). Most (81%) episodes were bronchiolitis. Forty-nine (9.0%) infants were hospitalized at least once with an LRTI. There were 53 hospitalizations (45.7%) for 116 LRTI episodes. None of these infants were breastfed. The odds of LRTI in infants whose mothers had CD4% <14 at enrollment were 4.4 times those of infants whose mothers had CD4% ≥29 (p=0.003). The odds of LRTI in infants with a CD4+ count (cells/mm(3)) <750 at hospital discharge were 16.0 times those of infants with CD4+ ≥750 (p=0.002). Maternal CD4+ decline and infant hemoglobin at the 6-12 week visit were associated with infant LRTIs after 6-12 weeks and before 6 months of age. CONCLUSIONS Acute bronchiolitis is common and frequently severe among HIV-exposed, uninfected infants aged 6 months or less. Lower maternal and infant CD4+ values were associated with a higher risk of infant LRTIs. Further understanding of the immunological mechanisms of severe LRTIs is needed.

Low risk for tuberculosis in a regional pediatric hospital: nine-year study of community rates and the mandatory employee tuberculin skin-test program.

OBJECTIVE To assess the risk of Mycobacterium tuberculosis infection and disease among patients and workers in a regional pediatric hospital. DESIGN Descriptive epidemiological study of the mandatory tuberculin skin testing program of hospital employees at hire and during annual reevaluation, pediatric patients with tuberculosis (TB), efficacy of hospital infection control measures, and community rates of TB. SETTING 361-bed, university, pediatric hospital serving Cincinnati (1.7 million population). RESULTS During 1986 through 1994, 2,275 to 4,356 employees were compliant with Mantoux skin testing and screening each year. This represented >97% of the population who were eligible for screening. The cumulative rate of M tuberculosis infection from a previous positive tuberculin skin test was 10% to 12% per year during 1986 through 1994. Among new Mantoux skin-test converters in employees at annual reevaluation, the risk of TB infection was 0.3% in 1993 and 1994. There were no active cases of TB identified during new employee screening or annual reevaluation. Of 62 new Mantoux skin-test converters in 9 years, 23% were foreign-born, 13% were Asian, 23% were African American, 11% received the bacillus of Calmette-Guérin vaccine, and 60% had direct patient care or indirect patient contact. A cluster of five converters occurred in a department with no patient care or contact. Mantoux conversion rates were 1.9 per 1,000 employee patient-care or contact-years and 2.2 per 1,000 employee non-patient-contact years. Twenty pediatric patients with active TB were identified during 1991 to 1994, with < or =6 cases per year, placing this hospital in the low-risk category for M tuberculosis disease. Three children with pulmonary TB were admitted without immediate respiratory isolation, possibly exposing 9 patients and 42 employees; none converted their Mantoux skin tests on retesting. Rates of active TB in Cincinnati were stable during the period (eg, 8/100,000 population in 1994). CONCLUSIONS Despite intense active surveillance among thousands of hospital employees with >97% annual compliance, tuberculin conversion rates were low, and no cases of active TB were identified during 9 years of follow-up. There was no evidence of transmission of M tuberculosis from infected patients to employees during uncontrolled exposures. Rates of TB in the community were low. These data suggest that rigorous application of the Centers for Disease Control and Prevention guidelines and Occupation Safety and Health Administration regulations for preventing nosocomial TB in pediatric hospitals may be excessive and costly. Special provisions should be made for pediatric hospitals with a proven low risk of transmission of M tuberculosis.

Student self-assessment in a paediatric objective structured clinical examination

OBJECTIVE The objective structured clinical examination (OSCE) has been recognized not only as a useful assessment tool but also as a valuable method of promoting student learning. Student self-assessment is also seen as a means of helping students recognize their strengths and weaknesses, understand the relevance of core learning objectives and to take more responsibility for each stage of their work The authors sought to evaluate the accuracy of medical student self-assessment of their performance in the paediatric clerkship OSCE and thus obtain preliminary data for use in programme strengthening. DESIGN AND METHODS A self-administered questionnaire was completed by successive groups of students immediately after the OSCE at the end of each clerkship rotation. Students assessed their performance at each station, using a performance rating scale. Performance data were summarized using descriptive and non-parametric tests. Basic statistical analysis of the Likert items was conducted by calculatingfrequencies, means and standard deviations. Regression analysis was used to correlate self-reported rating and actual performance in each station. A p value of < 0.05 was considered significant. Eighty-one students (92%) completed the questionnaire. RESULTS Fifty-eight (72%) of the students achieved greater than minimum competence in their overall scores. Significant positive correlation (p < 0.05) between student self-rating and actual score was noted- among the following stations: technical skills, cardiovascular examination, assessment of dysmorphism, dermatology, communication and photographic interpretation stations. Students overestimated their performance in the gastrointestinal examination, radiological and arterial blood gas interpretation. Students underestimated their performance in the following: respiratory system, examination of the head, developmental and nutritional assessment. CONCLUSIONS The findings highlight the perceived strengths and weaknesses in clinical competence and self-assessment skills and provide direction for programme training needs.

Seroepidemiology of Human Bocavirus Infection in Jamaica

Background Human bocavirus (HBoV) is a newly identified human parvovirus. HBoV is associated with upper and lower respiratory tract infections and gastroenteritis in children. Little is known about the seroepidemiology of HBoV in populations in the Caribbean. Methods In a cross-sectional study conducted at the University Hospital of the West Indies in Kingston, Jamaica, 287 blood samples were collected from pediatric patients and tested for the presence of HBoV-specific antibody using a virus-like-particle based enzyme-linked immunosorbent assay (ELISA). Results HBoV-specific antibodies were found to be present in 220/287 (76.7%) of samples collected from the pediatric population. Seroprevalence of HBoV was highest in those ≥2 years old. The seroepidemiological profile suggests that most children are exposed to HBoV during the first two years of life in Jamaica. Conclusion HBoV infection is common in children in Jamaica. HBoV seroprevalence rates in the Caribbean are similar to those previously reported in other areas of the world.