NIPH annals最新文献

A placebo controlled, double blind efficacy trial with a new outer membrane vesicle vaccine against systemic meningococcal disease of serogroup B, has been conducted in Norwegian secondary schools. The study was randomized at school level (1335 schools) and 171,800 students volunteered. The study started in October 1988 and the code was opened in June 1991. Out of the thirty-six proven cases of acute, severe, systemic disease caused by serogroup B meningococci among the participants, twelve occurred in eleven schools given vaccine, twenty-four in twenty-four schools given placebo. twenty-four cases were recorded among secondary school students who did not participate in the study. The protection rate was calculated to 57.4% with a p-value of 1.2% and lower limit of confidence (95%) to 27.7%. The results have initiated research towards an improved outer membrane vesicle vaccine against this disease.

Results from the serum bactericidal assay (BA) after immunization of human volunteers with the Norwegian serogroup B meningococcal outer membrane vesicle vaccine are surveyed. In the phase II trials with adults we found very high seroconversion rates (greater than 98%) against the vaccine strain in the BA. Details in the antigenic composition of the inoculum used in the BA seem very important as shown here by finding lower bactericidal titres with teenager sera when tested with a variant of the standard inoculum. The present preliminary report corresponds to the presentation given at the Report Meeting on the Norwegian Meningococcal Vaccine Trial, Oslo, 12 September, 1991.

The "Gold standard" in vaccine testing is the randomized, placebo controlled, double-blind efficacy trial. Once a protective immune mechanism is defined, e.g., from an efficacy trial, vaccine performance can then be judged by serologic parameters. Although immunogenicity studies can provide important information, in many instances the answer has to come from efficacy trials. For rare diseases like meningococcal disease, these trials are expensive and difficult to conduct. It is therefore incumbent to learn as much as possible from each trial. Issues in pre-licensure studies include: vaccine selection, site selection, trial design, assignment to treatment and control groups, definition and surveillance for endpoints (cases, adverse reactions), identification of surrogate markers for protection, and utilization of monitoring committees.

Two different antisyphilis screening tests based on cardiolipin antigen, the VDRL test and an RPR test (Sysmic, Diagast), were compared. A total of 2155 sera were examined by both tests. Positive results were confirmed with TPHA and TPI tests. RPR Sysmic test was as sensitive and specific as the VDRL. However, the RPR Sysmic test was easier and quicker, especially when the number of sera tested was high.

The clinical and laboratory findings in 176 patients hospitalized with suspected systemic meningococcal disease (MCd) are presented. All except nine patients were prospectively included in the MenOPP study. One hundred and fifteen patients were most likely to have meningococcal disease, of these 71 were confirmed with growth of meningococci in blood and/or cerebrospinal fluid (CSF). The remaining sixty-one patients served as the control group. Both petechiae, reduced general condition, and reduced consciousness proved valuable in the diagnosis of MCd. Petechiae was the clinical sign best discriminating between MCd and the control group. Ecchymoses were specific for meningococcal disease. Among the laboratory tests C-reactive protein (CRP) and Thrombotest (TT) were the tests which most frequently were found to be abnormal in patients with meningococcal disease. A diagnostic score is computed by the aid of a multiple regression analysis. This score includes the variables skin hemorrhages, body pain, CSF cell count, TT, CRP and white blood cell count. For a patient hospitalized with suspected MCd a score of three or more supports the diagnosis and should indicate the need for rapid antibiotic therapy.

Sixty-three sera were analysed for antibodies against Borrelia burgdorferi with an in-house indirect immunofluorescence assay. Thirty-nine sera were positive (titer greater than or equal to 256), seven borderline (titer 128) and 17 negative (titer less than or equal to 64). These results were compared with results obtained with four different commercial assays for detection of such antibodies. Indirect immunofluorescence tests yielded most positive results. The flagellin ELISA test detected antibodies in patients with erythema chronicum migrans (ECM) more often than the other test systems. Sera from patients with acrodermatitis chronica atrophicans (ACA) were positive in all systems. The serological diagnosis of borreliosis is difficult and direct methods for detecting the presence of the microbe are highly needed.