Showing papers by "Geert-Jan Dinant published in 1994"

The Efficacy of Influenza Vaccination in Elderly Individuals: A Randomized Double-blind Placebo-Controlled Trial

Abstract: Objective. —To determine the efficacy of influenza vaccination in elderly people. Design. —Randomized double-blind placebo-controlled trial. Setting. —Fifteen family practices in the Netherlands during influenza season 1991-1992. Participants. —A total of 1838 subjects aged 60 years or older, not known as belonging to those high-risk groups in which vaccination was previously given. Intervention. —Purified split-virion vaccine containing A/Singapore/6/86(H1N1), A/Beijing/353/89(H3N2), B/Beijing/1/87, and B/Panama/45/90 (n=927) or intramuscular placebo containing physiological saline solution (n=911). Main Outcome Measures. —Patients presenting with influenzalike illness up to 5 months after vaccination; self-reported influenza in postal questionnaires 10 weeks and 5 months after vaccination; serological influenza (fourfold increase of antibody titer between 3 weeks and 5 months after vaccination). Results. —The incidence of serological influenza was 4% in the vaccine group and 9% in the placebo group (relative risk [RR], 0.50; 95% confidence interval [CI], 0.35 to 0.61). The incidences of clinical influenza were 2% and 3%, respectively (RR, 0.53; 95% CI, 0.39 to 0.73). The effect was strongest for the combination of serological and clinical influenza (RR, 0.42; 95% CI, 0.23 to 0.74). The effect was less pronounced for self-reported influenza. Conclusion. —In the elderly, influenza vaccination may halve the incidence of serological and clinical influenza (in periods of antigenic drift). (JAMA. 1994;272:1661-1665)

Reliability of C-reactive protein measurement in general practice in The Netherlands

Abstract: The aim of this study was to compare the reliability of the whole blood NycoCard C-reactive protein measurement (CRP) with the erythrocyte sedimentation rate (ESR) in four general practice centres (GPCs) in The Netherlands with 443 patients indicated for ESR. During 4 successive months in 1992 NycoCard CRP was measured in capillary (whole) blood at the GPC. A venous blood sample was then transported to the local hospital laboratory in order to determine CRP turbidimetrically in plasma. Westergren's ESR was measured at the GPC and at the laboratory. The dichotomized CRP values measured at the GPCs corresponded with the laboratory values in 88% of the cases. Kappa was 65% (p < 0.00001). Using a 20 mm cut-off point, ESR values measured at the GPCs and the laboratory corresponded in 96% of cases (Kappa = 90%, p < 0.00001). Interpractice variabilities and learning effects did not influence the results. 'False normal' rates for CRP and ESR were 8% and 1%; 'false elevated' rates were 28% and 12% respectively. The reliability of the NycoCard CRP measurement in whole blood disappointed. In particular the 'false elevated' rate is unacceptably high for daily general practice. The background of the poor reliability remains unclear.