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Biomedical subjects

C B Hall

Publications and source records attributed to C B Hall.

At least 55 records · Page 3Linked to original sources
PubMed1995

Is underimmunization a marker for insufficient utilization of preventive and primary care?

OBJECTIVE: To test the hypothesis that the underimmunization of young children is a marker for the lack of preventive and acute primary care. SETTING: Primary care center serving an impoverished population (90% Medicaid). DESIGN: Historical cohort study (N = 1178) of children aged 12 to 30 months that determined each child's immunization status, anemia, tuberculosis, and lead screening status; and office utilization history. Screening delay was defined as missing a recommended screening by more than 3 months past the standard screening age. RESULTS: Thirty-four percent of the population were underimmunized at 12 months of age. Compared with fully immunized children, these children were at greater risk for screening delay: anemia, 38% vs 5% (risk ratio [RR], 7.5; 95% confidence interval [CI], 5.4 to 10.4); tuberculosis, 76% vs 44% (RR, 1.7; CI, 1.6 to 1.9); and lead, 69% vs 33% (RR, 2.1; CI, 1.9 to 2.4). These RRs increased with greater immunization delay. Compared with fully immunized children, the underimmunized group made 47% fewer preventive health visits (2.5 vs 4.7 visits per infant per year, P < .001) and 43% fewer illness visits (2.5 vs 4.4, P < .001) and had 50% more missed appointments (2.1 vs 1.4, P < .001). Logistic regression, predicting anemia screening delay at 12 months of age, showed that underimmunization had an effect independent of utilization, with an odds ratio of 7.7 (CI, 5.2 to 12.0). CONCLUSION: Underimmunization was a powerful, independent marker for inadequate health supervision in this population. IMPLICATIONS: The current emphasis on immunizations has the benefit of targeting children at risk of lack of preventive and acute care. Improving immunization rates may have the potential to improve other aspects of primary care if immunization provision is not uncoupled from primary care.

Child Health Services↗
PubMed1995

Direct sequence analysis of human herpesvirus 6 (HHV-6) sequences from infants and comparison of HHV-6 sequences from mother/infant pairs.

Direct sequence analysis of polymerase chain reaction-amplified DNA fragments from the large tegument protein (LTP) gene of human herpesvirus 6 (HHV-6) was performed with use of uncultured peripheral blood mononuclear cells (PBMCs) from four mother/infant pairs. In two cases, LTP gene sequences were identical in paired mother/infant specimens, thus suggesting that mother-to-infant transmission of HHV-6 may have occurred. The genetic stability of HHV-6 strains was confirmed by the fact that there was no difference between amplified DNA fragments from sequential PBMC samples from two of two infants analyzed. In contrast, a change in the amplified viral strain was detected in an infant who had reinfection with HHV-6 variant B (HHV-6B). Furthermore, HHV-6B strains concurrently amplified from saliva and PBMCs from an adult were found to be different. The data suggest that HHV-6 may be frequently transmitted from mother-to-infant and that reinfection with HHV-6B may occur.

Adult↗
PubMed1995

Sequelae of respiratory syncytial virus infections. A role for intervention studies.

The association between respiratory syncytial virus (RSV) infections in infancy and respiratory abnormalities later in life has been attributed both to a direct effect of the infection itself and to an inherent susceptibility. Observational studies do not allow a rigorous test of these hypotheses. Respiratory syncytial virus infection is universal in the first years of life and no uninfected control group exists. Randomized, controlled trials using new prophylactic agents such as vaccines or specific therapeutic agents will provide a powerful test of the relationship between RSV infection and long-term respiratory sequelae.

Adult↗
PubMed1995

Cellular localization of human herpesvirus-6 in the brains of children with AIDS encephalopathy.

Human herpesvirus-6, the etiologic agent of exanthem subitum, is a ubiquitous virus that infects almost all children by the age of 2 years and that has previously been shown to be neuroinvasive. These characteristics suggest that human herpesvirus-6 may be important in the neuropathogenesis of acquired immune deficiency syndrome (AIDS) in children. To address this hypothesis, we evaluated postmortem pediatric brain tissues for the presence of human herpesvirus-6 infection. Using in situ hybridization with a digoxigenin-labeled DNA probe for the large tegument protein gene of human herpesvirus-6, we detected nuclear signals in postmortem brain tissue from 4/5 children with human immunodeficiency virus-1 encephalitis. Human herpesvirus-6 DNA was found in numerous oligodendrocytes of the white matter and less frequently in astrocytes, macrophages, microglia and neurons. The human herpesvirus-6 positive cells detected by in situ hybridization were not immunoreactive either for human herpesvirus-6 early nuclear phosphoproteins or for surface glycoproteins associated with productive infection. Only rare human herpesvirus-6 infected cells were found in age-matched control brain tissues. No human herpesvirus-6 infected cells were found in human fetal brain tissue. These data suggest that human herpesvirus-6 is more extensively disseminated in neural cells in the presence of human immunodeficiency infection and immunodeficiency in pediatric AIDS patients, and it may contribute to the pathogenesis of AIDS encephalopathy.

AIDS Dementia Complex↗
PubMed1994

Human herpesvirus-6 infection in children. A prospective study of complications and reactivation.

BACKGROUND: Infection with human herpesvirus-6 (HHV-6) is nearly universal in infancy or early childhood. However, the course of this infection, its complications, and its potential for persistence or reactivation remain unclear. METHODS: We studied infants and children under the age of three years who presented to our emergency department with acute illnesses. Infants and young children without acute illness were studied as controls. HHV-6 infection was identified by blood-mononuclear-cell culture, serologic testing, and the polymerase chain reaction (PCR). RESULTS: No primary HHV-6 infection was found among 582 infants and young children with acute nonfebrile illnesses or among 352 controls without acute illness. Of 1653 infants and young children with acute febrile illnesses, 160 (9.7 percent) had primary HHV-6 infection, as documented by viremia and seroconversion. They ranged in age from 2 weeks to 25 months; 23 percent were under the age of 6 months. HHV-6 infections accounted for 20 percent of 365 visits to the emergency department for febrile illnesses among children 6 to 12 months old. Of the 160 infants and young children with acute HHV-6 infections, 21 (13 percent) were hospitalized, and 21 had seizures. Often the seizures appeared late and were prolonged or recurrent. HHV-6 infections accounted for one third of all febrile seizures in children up to the age of two years. In follow-up studies over a period of one to two years, the HHV-6 genome persisted in blood mononuclear cells after primary infection in 37 of 56 children (66 percent). Reactivation, sometimes with febrile illnesses, was suggested by subsequent increases in antibody titers in 16 percent (30 of 187) and by PCR in 6 percent (17 of 278). No recurrent viremia was detected. Of 41 healthy newborns studied, 12 (29 percent) had the HHV-6 genome in their blood mononuclear cells; nevertheless, 6 of these newborns subsequently had primary HHV-6 infections. CONCLUSIONS: In infants and young children HHV-6 infection is a major cause of visits to the emergency department, febrile seizures, and hospitalizations. Perinatal transmission may occur, with possible asymptomatic, transient, or persistent neonatal infection.

Acute Disease↗
PubMed1994

Efficacy and safety of aerosolized ribavirin in young children hospitalized with influenza: a double-blind, multicenter, placebo-controlled trial.

We randomly assigned children hospitalized with influenza who had been ill < or = 48 hours and who had a temperature > or = 37.8 degrees C to receive either ribavirin or placebo. All patients had evaluations performed for fever reduction, use of acetaminophen for temperature > or = 38.3 degrees C, duration and severity of influenza symptoms, and feeding behavior. Sixty-two patients (35 in the placebo group, 27 in the ribavirin group) had a diagnosis of influenza confirmed by laboratory study. The groups did not differ significantly in age, initial signs and symptoms, or in distribution of influenza A or B infections. The time to reduction of temperature < or = 38.3 degrees C for the ribavirin group was 8.9 hours compared with 22.6 hours for the placebo group (p = 0.04). The mean duration of acetaminophen use was 7.4 hours in the ribavirin group and 16.3 hours in the placebo group (p = 0.14). There were no significant differences between the groups in outcome of respiratory rate, pulse rate, cough, or level of consciousness. Convalescent influenza antibody geometric mean titer for the placebo group was 9.8 compared with 3.6 for the ribavirin group (p = 0.04). Ribavirin was more effective than placebo in accelerating normalization of temperature but there were no other significant differences.

Acetaminophen↗
PubMed1994

Total body water in pregnancy: assessment by using bioelectrical impedance.

Determinations of total body water (TBW) calculated from deuterium dilution spaces and bioelectrical-impedance measurements were made serially in a group of 15 women before, during, and after pregnancy. Similar measurements were made once in a group of 50 nonpregnant women and intermittently in another group of 10 women during pregnancy and postpartum. TBW increased significantly during pregnancy, then decreased postpartum. Estimates of TBW in pregnancy and postpartum calculated with models derived from nonpregnant and pregnant women were similar to measured values. Changes in reactance and resistance explained more of the variance in predicting changes in TBW than did body weight, abdominal circumference, or hematocrit (50-75% vs 4-50%, respectively). Changes in TBW estimated with the nonpregnancy impedance model were significantly different than either the measured changes or changes predicted with the pregnancy impedance model. These findings indicate that the impedance method is a practical and valid method for determining longitudinal changes in TBW.

Adult↗
PubMed1994

Neuroinvasion and persistence of human herpesvirus 6 in children.

Human herpesvirus 6 (HHV-6) causes a febrile illness in children and has been implicated as a cause of encephalitis and recurrent seizures. Paired samples of cerebrospinal fluid (CSF) and peripheral blood mononuclear cells (PBMC) from 487 children were evaluated by nested polymerase chain reaction (PCR) for evidence of current or past infection with HHV-6. PBMC were also cultured for isolation of HHV-6. These data were correlated with the patients' clinical information. HHV-6 DNA was detected in 72 (14.8%) of 487 CSF samples. HHV-6 persistence was documented in 142 children by PCR detection of HHV-6 DNA in PBMC or CSF (or both) in the absence of primary HHV-6 infection; the central nervous system was the only site of HHV-6 DNA persistence in 28.9%. HHV-6 DNA can be detected in the CSF of children during and after primary infection, and the central nervous system may be the sole site of persistence.

Child, Preschool↗
PubMed1994

Parainfluenza viral infections in pediatric outpatients: seasonal patterns and clinical characteristics.

Parainfluenza types 1, 2 and 3 were studied in a pediatric outpatient population from 1976 to 1992 to compare seasonal patterns over time and to define better the spectrum of illness in all ages of children caused by these viruses. Parainfluenza type 1 occurred in the fall of odd numbered years; parainfluenza type 2 was less predictable; and parainfluenza type 3 appeared yearly with peak activity in spring or summer. The parainfluenza viruses were the major cause of croup and also accounted for one-half of the cases of laryngitis and over one-third of all lower respiratory tract illness in children from whom a virus was isolated. The major clinical manifestations of infection with parainfluenza types 1 and 2 were croup, upper respiratory infections and pharyngitis; for parainfluenza type 3 upper respiratory tract infection was predominant in all age groups. The parainfluenza viruses cause appreciable respiratory morbidity each year among infants and young children. They are the major cause of croup but also produce a spectrum of diseases ranging from mild upper respiratory tract infection to bronchiolitis and pneumonia. Most studies have focused on the morbidity of parainfluenza viruses in infants and young children who are hospitalized. Less appreciated is the impact of parainfluenza viral infections in outpatients and in older children. The parainfluenza viruses have a striking epidemiologic pattern which has evolved over the past 30 years. In the early 1960s parainfluenza types 1, 2 and 3 were all reported to be endemic.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Immunization practices of pediatricians and family physicians in the United States.

OBJECTIVE: To assess current practices and attitudes among pediatricians and family physicians across the United States regarding immunizations. DESIGN: Survey of a random sample of pediatricians and family physicians. SUBJECTS: Fellows of the American Academy of Pediatrics (N = 746) and American Academy of Family Medicine (N = 429). SURVEY TOPICS: General immunization practices (eg, types of visits during which vaccinations are provided, mechanisms to identify undervaccinated children); and opinions about perceived barriers to immunizations, acceptance of alternative sites for immunizations, and possible immunization requirements for Medicaid and The Special Supplemental Food Program for Women, Infants, and Children (WIC). RESULTS: Pediatricians and family physicians (combined) reported the following: immunizing children during acute illness visits (28%), follow-up visits (90%), and chronic illness visits (77%); using computer or reminder files to identify undervaccinated children (13%); and simultaneously administering four vaccines (diphtheria-tetanus-pertussis, oral poliovaccine, measles, mumps, and rubella and Haemophilus influenzae type b) to an eligible 18-month-old child (66%). Physicians perceived the following as barriers to immunizations: missed preventive visits (40%), vaccine costs (24%), lack of insurance coverage (24%), inability to track undervaccinated patients (22%), incomplete immunization records (12%), and missed vaccination opportunities (12%). Physicians agreed with offering vaccinations during hospitalizations (51%) or emergency department visits (30%), and with immunization requirements for continued eligibility for Medicaid (66%) or WIC (64%). Pediatricians were more likely to vaccinate during chronic illness and follow-up visits, and were more likely to use systems to track undervaccinated children (P < .05); however, most immunization practices and attitudes of pediatricians and family physicians were similar. Physicians who graduated from medical school more recently and those in high-risk urban practices were more likely to vaccinate during acute illness visits, provide simultaneous vaccinations, and favor vaccinations in hospital settings. CONCLUSIONS: Vaccination rates might be improved by closer adherence to current immunization guidelines regarding vaccinations during all encounters and simultaneous vaccinations, by developing systems to identify undervaccinated children, and by reducing patient costs for vaccinations. Current immunization practices fall short of the immunization guidelines; changes in individual practice styles will be required to conform with these standards.

Acute Disease↗
PubMed1993

Prophylactic administration of respiratory syncytial virus immune globulin to high-risk infants and young children. The Respiratory Syncytial Virus Immune Globulin Study Group.

BACKGROUND: Infants with cardiac disease or prematurity are at risk for severe illness caused by respiratory syncytial virus. Immune globulin with a high titer of antibodies against respiratory syncytial virus may offer infants and young children at risk protection from this serious, common respiratory illness. METHODS: We studied 249 infants and young children (mean age, eight months) who had bronchopulmonary dysplasia due to prematurity (n = 102), congenital heart disease (n = 87), or prematurity alone (n = 60). Respiratory syncytial virus immune globulin was given monthly to some of these children in either a high dose (750 mg per kilogram of body weight; n = 81) or low dose (150 mg per kilogram; n = 79); 89 controls received no immune globulin. Group assignments were random. Assessments of respiratory illness and management were conducted without knowledge of the children's group assignments. RESULTS: There were 64 episodes of respiratory syncytial virus infection: 19 in the high-dose group, 16 in the low-dose group, and 29 in the control group. In the high-dose group there were fewer lower respiratory tract infections (7, vs. 20 in the control group; P = 0.01), fewer hospitalizations (6, vs. 18 in the control group; P = 0.02), fewer hospital days (43, vs. 128 in the control group; P = 0.02), fewer days in the intensive care unit (P = 0.05), and less use of ribavirin (P = 0.05). In the low-dose group there was a significant reduction only in the number of days in the intensive care unit (P = 0.03). Adverse events during the 580 infusions were generally mild and included fluid overload (in five children), oxygen desaturation (eight), and fever (six). Six children died: three in the high-dose group, three in the low-dose group, and none in the control group (P = 0.15), but no death was attributed to the use of immune globulin or to illness caused by respiratory syncytial virus. CONCLUSIONS: Administration of high doses of respiratory syncytial virus immune globulin is a safe and effective means of preventing lower respiratory tract infection in infants and young children at high risk for this disease.

Antibodies, Viral↗
PubMed1993

Decision rules for predicting vaccination status of preschool-age emergency department patients.

We produced and tested rules to predict undervaccination among preschool-age emergency department (ED) patients. Data were gathered on demographics, vaccination status, health status, and health care utilization from parents, ED physicians, and ED charts at an urban teaching hospital in Rochester, N.Y. Primary care charts were reviewed to verify vaccination status. Using recursive partitioning, we developed decision rules to predict undervaccination. Decision rules were developed on a sample of 602 ED patients 4 to 48 months of age and then prospectively tested on 1832 ED patients aged 6 to 36 months. Factors associated with undervaccination for any vaccine included parental report of vaccination delay (odds ratio = 8.1; p < 0.001), inability to report the receipt of the appropriate number of vaccines (odds ratio = 4.5; p < 0.001), lack of health insurance (odds ratio = 3.6, p < 0.001), elapsed time since the last visit to primary care provider (p < 0.001), household size (p < 0.001), and maternal age (p < 0.01). Eight decision rules were produced that varied in their number of questions (one to six), sensitivity (0.27 to 0.87), and specificity (0.54 to 0.98). No single rule was both highly sensitive and highly specific. The rules' sensitivities and specificities were similar for the validation sample of 1832 patients. Thus a decision rule could not be produced that was both sensitive and specific. Identification of undervaccinated children by means of information available at an ED visit is inherently difficult. Interventions in the ED may be inefficient unless better methods of assessing vaccination status can be developed.

Child↗
PubMed1993

Antigenic and nucleic acid analysis of nosocomial isolates of respiratory syncytial virus.

Monoclonal antibodies and ribonuclease protection were used to analyze antigenic and genomic diversity among 42 isolates of group A respiratory syncytial virus (RSV) from studies of nosocomial RSV carried out at the University of Rochester during the 1974-1975 and 1975-1976 RSV seasons. Three distinct subgroups or lineages and a total of 12 viral variants were present. Against this background of diversity, an outbreak was recognized that included 13 indistinguishable isolates occurring during a 2-week period. This outbreak accounted for 6 of the 8 infants with nosocomial infection. In contrast to the limited diversity of the nosocomial isolates, isolates from the 10 infants with community-acquired infection included 8 variants. Like those from community outbreaks of RSV, isolates of RSV from hospitalized patients are virologically heterogeneous. However, discrete outbreaks associated with transmission of a single strain can occur.

Acute Disease↗