• Appendix

Methods of Signal Detection

The identification of signals in the national pharmacovigilance (PV) centre’s database, or another database, of adverse events or suspected adverse reactions requires careful review of individual reports and events.

Careful, informed, routine, systematic and standardized clinical review of the Centre’s reports with the recording and appropriate collation of good data provides the quickest and most satisfying way of identifying previously unsuspected adverse reactions. Following through the whole process from relationship assessment, to signal identification, to signal strengthening, to communicating the findings is essential.

It is important to stress that new pharmacovigilance systems may have very few reports and may not be able to detect signals using statistical methods, but may be able to do case by case signal detection. PV centres should follow closely what is going on in other centres and also rely on the WHO Pharmaceuticals Newsletter and the signal document prepared by the WHO Collaborating Centre for International Drug Monitoring, UMC to keep abreast of signals that may be of importance to them. International collaboration is key to both signal identification and signal strengthening, and should be encouraged.

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