The international community generally recognizes the importance of adopting adequate, timely and continuously updated prevention measures to reduce the risk of global health emergencies and pandemics. Nevertheless, as demonstrated by COVID-19, with its assumed mutation capacity, even the most sophisticated preventive measures cannot avoid the spread of new diseases. States are expected, therefore, to adopt specific preparedness measures to effectively anticipate, respond to, and recover from the impacts of likely pandemics. These measures have gained increasing interest in many treaties all over the world. The present article investigates the international obligations codified in universal instruments related to the adoption of preparedness measures for potential pandemics. Carefully examining relevant international treaties as well as emerging soft-law instruments, it will attempt to answer a pertinent question that has been raised time and again in the past and continues to be raised during the current COVID-19 crisis: are the existing preparedness measures still relevant and adequate or have they become obsolete or misleading? Since more COVID-19 viral waves are expected to arrive in the next months, the urgency of adopting adequate preparedness measures is even more evident. Moreover, the article analyses the current worldwide challenges related to the national implementation of preparedness measures. Considering the innovative drugs and diagnostics that are currently available, and that we can count on new technology platforms that significantly reduce the time needed to develop vaccines, it argues that inaction can no longer be justified, whether in legal, political or moral terms.