Abstract

A safety signal is defined as information suggesting a new potential association or new aspects of a known association between medicines and adverse reaction(s) that warrant further investigation. The way a safety signal is detected and evaluated changed a lot during the last years. Different methods can be used and each of them has caveats and advantages to be considered. During the last two global pandemics (H1N1 and COVID-19), the pharmacovigilance world changed extensively to adapt and meet unprecedented needs. Literature review and observed vs expected analysis played a key role in signals evaluation. Various alternative sources of signals, such as social media monitoring have been explored for the Covid-19 vaccines worldwide. The increased level of communication about safety data between companies and regulatory authorities, helped to turn the pandemic into an opportunity to make important steps forward in the pharmacovigilance area.