Abstract

Adverse events following immunisation (AEFI) in the National Vaccination Programme of the Netherlands (RVP) have been monitored through an enhanced passive surveillance system by RIVM since 1962. From 1984 onwards evaluation is done in close collaboration with the National Health Council. Reports from Health Care workers are received mainly by telephone through the operating vaccine information and advisory service. Further data are obtained, if necessary, from parents, general practitioner, paediatrician etc. After supplementation and verification of data a (working) diagnosis is made and causality assessed. In this report on 1998 an overview of all received AEFI is presented with classification according to case definitions and causality. Reporting bias, background rates of specific events and possible pathophysiology of symptoms are discussed. On a total of approximately 2 million vaccinations 1100 AEFI were submitted. Of these 1.5% (16) was unclassifiable because of missing information. In 80% (877) of the classifiable events a possible causal relation with vaccination was established and in 18% (197) the events were judged to be coincidental. Compared to 1997 there was again a rise in the number of notifications. This increase is thought to be due, both to decreased underreporting, increased awareness and apprehension as possibly also to some increase in true side effects, mainly fever and crying.