[Assessing the risk-benefit balance of medicines: Some lessons from Covid-19]

The efficacy of medications is evaluated by clinical trials. However, such trials are not designed to assess adverse effects, particularly when those are rare. A robust pharmacovigilance system is therefore required to assess risks, supplemented as requested by pharmacoepidemiology studies. The benefits of medications are expressed in either relative or absolute terms and they vary depending on the baseline risk of the disease (its severity, potential complications, progression, and its incidence for the population-level benefits). This is not the case for adverse effects, which are influenced by the drug characteristics and the population receiving the treatment. In this context, can we truly balance the benefits and risks of medications? The experience of Covid-19 illustrates the complexity of this concept. It clearly highlights the need for a comprehensive approach, integrating analysis of clinical trials, pharmacovigilance monitoring, pharmacoepidemiology studies, and the detection of potential drug interactions. Finally, it is essential to inform and educate the general public about medications. This empowers individuals to accurately understand the complex concept of benefit-risk balance, prevents misleading over simplifications, and helps effectively counter misinformation.