Vermeer-de Bondt PE, Moorer-Lanser N, PHaff TAJ, Oostvogels B, Wesselo C, van der Maas NAT
RIVM Rapport 205051004
In 2010, 800,000 children received one or more vaccines on 1.3 million dates, with more than 7 million vaccine components. There is always some chance of adverse reactions but these are usually not severe, though sometimes frightening. This year, RIVM received 1380 reports of adverse events following immunisation (AEFI). This is 16% less than in 2009 when 2 vaccination campaigns raised considerable adverse publicity with subsequent increase in reports. Data show that the benefit of the vaccination programme outweighs the risk of adverse reactions by far.
Safety surveillance: necessary part of the vaccination programme. Enhanced safety surveillance has been an integral part of the vaccination programme since 1962. Annual reports have been published since 1983, following independent reevaluation. The surveillance system of the Netherlands enjoys very high reporting rates and is highly sensitive for signals. It allows individual follow-up because of name-based reporting. In this last year of safety surveillance in this setting, we present an overview of results since 1994. This brings some new insights.
Careful reporting and validation system. All reports were validated and complemented, preferably also with eyewitness accounts (92%). Final assessment followed according to case definitions and causality criteria. The embedding of the safety surveillance in the telephone consultation service has contributed to the quality of the reports.
Reported adverse events. In 2010, 78% of reports (1082) had possible causal relation with the vaccination. These concerned major adverse reactions in 48% (523), including very high fever (>40.5 °C), persistent screaming, collapse, discoloured legs, febrile convulsions or atypical attacks with chills, myoclonics or hyper/hypo-tonicity. Altogether 22% (296) of reports were chance occurrences. Reported severe infections and epilepsy had no causal relation with the vaccinations. In addition, none of the 5 reports on death was related to vaccination. An independent expert committee has reassessed these severe adverse events.