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D A Clements

Publications and source records attributed to D A Clements.

36 records · Page 2Linked to original sources

Cost of treatment and prevention of Haemophilus influenzae type b disease. An international perspective.

On the basis of immunogenicity and protective efficacy studies, 4 Haemophilus influenzae type b (Hib) conjugate vaccines have been licensed for administration to infants and children. Population based studies of Hib disease from Australia, Chile, Finland, Gambia, Israel, Switzerland, UK and US show that the relative and absolute incidence of Hib disease varies significantly. These differences in Hib epidemiology, and associated sequelae and hospital costs affect the cost-benefit analysis of preventive vaccination, necessitating unique calculations for each country. Published papers on the cost of Hib disease and the cost-benefit relationship of Hib vaccination have been based primarily on reports from the US, but more recently also on studies from Australia, Finland, Israel, Switzerland, UK, Sweden and Chile. All studies to date have produced favourable cost-benefit ratios. The implementation of Hib vaccination has led to the virtual disappearance of Hib disease in some of these countries. The lessons gained from these analyses are instructive not only for better understanding of the epidemiology of Hib disease, but also as a template for assessing the cost-benefit ratio of the implementation of preventive vaccination for other diseases.

Cost-Benefit Analysis↗

Comparison of the epidemiology and cost of Haemophilus influenzae type b disease in five western countries.

To determine and compare the cost of Haemophilus influenzae type b (Hib) disease in Australia, Finland, Israel, Switzerland and the United Kingdom a collaborative study was undertaken. The incidence of Hib disease varies in these 5 countries from 34 to 58.5 cases per 100,000 children less than 5 years of age. Although the incidence of meningitis in this age group is similar (between 18 and 26/100,000) in these countries, the incidence of epiglottitis varies from 0 to 22.7/100,000. The cost of hospitalization and the frequency of sequelae are similar for 4 of the 5 countries; however, the break even cost of a vaccination program to prevent 90% of Hib disease is estimated to vary from $22 to $84 per child (US$). Because of a lower incidence of Hib disease and lower cost for hospitalization, these costs are considerably less than those for the United States ($301.64 using similar calculations).

Australia↗

Activation of fibroblast growth factor (FGF) receptors by recombinant human FGF-5.

We have purified biologically active recombinant human fibroblast growth factor 5 (FGF-5) from Escherichia coli. In the presence of heparin, recombinant FGF-5 is as active as native growth factor, demonstrating that glycosylation does not significantly potentiate FGF-5 activity. FGF-5 can bind and induce autophosphorylation of human FGF receptors (FGFR) 1 and 2. Competition binding studies show that the KD for FGF-5-FGFR-1 and FGF-5-FGFR-2 interactions are both between 0.5 and 1.5 x 10(-9) M.

3T3 Cells↗

Socioeconomic risk factors for invasive Haemophilus influenzae type b disease.

Socioeconomic risk factors for primary invasive Haemophilus influenzae type b (Hib) disease include factors that increase exposure to Hib (day care attendance, presence of siblings, and crowded households) and factors that increase an individual's susceptibility to Hib infections (short duration of breast feeding, parental smoking, and frequent infections in general). These factors are consistently found to be associated with risk of Hib disease in studies conducted in populations that differ in their Hib disease epidemiology. However, there are large differences in the prevalence of these risk factors among populations. According to present knowledge, variations in the prevalence of socioeconomic risk factors may explain most of the differences in the epidemiology of Hib disease and may also contribute to the differences in Hib vaccine efficacy in different populations.

Breast Feeding↗

Outer membrane protein subtypes of Haemophilus influenzae type b isolates causing invasive disease in Victoria, Australia, from 1988 to 1990.

Outer membrane protein subtyping of 187 isolates of Haemophilus influenzae type b (Hib), isolated from children with invasive Hib disease in Victoria, Australia, showed that a single outer membrane protein subtype (1VA) was responsible for 83% of the infections. It was identical to that responsible for the majority of cases of invasive Hib disease in Europe.

Bacterial Outer Membrane Proteins↗

Haemophilus influenzae type b infections in Victoria, Australia, 1985 to 1987.

Invasive Haemophilus influenzae type b (HIB) infections occurring from 1985 to 1987 in children younger than 16 years of age living in the state of Victoria were reviewed. There were 547 cases which fulfilled the case definition, including 231 cases of meningitis, 219 of epiglottitis and 97 other infections; 14 (2.6%) children died, 8 with meningitis, 5 with epiglottitis and 1 with pneumonia. Ninety-five percent of cases occurred in children younger than 5 years of age, in whom the case attack rate was 58.5/100,000/annum. Nearly two-thirds of cases (46% of meningitis; 91% of epiglottitis; 45% of other infections) occurred in children more than 18 months of age (the age at which vaccine is presently given in the United States). Compared with the United States, the case attack rate for HIB disease in Victoria is lower, the mean age of affected children higher and the proportion with epiglottitis is greater. However, the incidence, age distribution and clinical manifestations of HIB disease in Victoria are similar to those described in Scandinavia before the successful introduction of vaccines. Effective conjugate vaccines against HIB disease are now available and the majority of cases are preventable (depending on the immunization schedule used). These data suggest that immunization of Victorian children against HIB infection should be cost-effective.

Adolescent↗

Antibody response of 18 month old children 1 month and 18 months following Haemophilus influenzae type b vaccine administered singly or with DTP vaccine.

Seventy-six children (aged 17-19 months) received 10 micrograms of Haemophilus influenzae type b polyribosyl-ribitol phosphate (PRP) vaccine, diluted with either phosphate-buffered saline (PBS) or diphtheria-tetanus-pertussis (DTP) vaccine, in a single-blind randomized trial. There were few side effects when PRP was administered alone. Before vaccination 37 of 76 children (49%) had non-protective antibody levels (less than 0.15 micrograms/mL); 26 of these 37 (70%) achieved antibody levels of greater than 0.15 micrograms/mL 1 month after vaccination. Before vaccination 16 of 76 (21%) had antibody levels of greater than 1.0 micrograms/mL; 1 month after vaccination 39 of 76 children (51%) achieved levels of greater than 1.0 micrograms/mL. Of 12 infants who had antibody levels less than 0.15 micrograms/mL 1 month after immunization, 10 had protective levels 18 months later. Administration of PRP mixed with DTP did not affect antibody response to PRP. The potential use and limitations of PRP vaccine are discussed.

Antibodies, Bacterial↗

Pertussis immunization in eight-month-old children in North Carolina.

Between 1984 and 1987 reported pertussis cases in North Carolina increased threefold. Pertussis immunization rates were examined for those years in three one-year cohorts drawn from a random selection of North Carolina birth records. The percentage of children immunized with three DTPs at eight months of age was 58.1, 58.6, and 56.7 for the three cohorts. Only 20.5 percent of 117 reported pertussis cases in children 9-36 months of age during the last 10 years were adequately immunized. The low pertussis immunization rate may have contributed to the recent increase in pertussis cases in North Carolina.

Child↗