Adverse events following immunisation under the National Vaccination Programme of the Netherlands. Number XII - Reports in 2005

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 until 2003 evaluation has been done in close collaboration with the Health Council. An RIVM expert panel continued the reassessment of selected adverse events from 2004 onwards. Reports were received mainly from Child Health Care professionals, primarily by telephone through the operating service for information and advice on vaccines and vaccinations. Further data have been obtained, if necessary, from parents, general practitioners, paediatricians and other professionals. After supplementation and verification of data a (working) diagnosis is made and causality assessed. In this annual report on 2005 an overview of all reported AEFI is presented with classification according to case definitions and causality. Trend analysis, reporting bias, background rates of specific events and possible pathophysiology of symptoms are discussed. On a total of over 1.4 million vaccination dates 1036 AEFI were reported. Of these, 5 (0.5%) were unclassifiable because of insufficient information. In 73% (752) of the classifiable events a possible causal relation with vaccination was established. These concerned major adverse reactions in 47% and minor adverse reactions in 53% of the reports. Of the reported adverse events 27% (279) were considered chance occurrences. Compared to 2004 and 2003 there was a decrease in number of reports with 52% and 25% respectively. The huge increase is 2004 was caused by repeated media attention about the safety of the formerly used whole cell pertussis vaccine. The decrease in 2005 was caused by the use of a new, acellular DPTP-Hib vaccine. The Netherlands Vaccination Programme has a very favourable risk balance