The COVID-19 has posed a wide range of urgent questions: about the disease, testing, immunity, treatments, and outcomes. Extreme situations, such as pandemics, call for exceptional measures. However, this threatens the production and application of evidence. This paper directs evidence production towards four types of uncertainty in order to address the challenges of the pandemic: Risk, Fundamental uncertainty, Ignorance, and Ambiguity. Eliminating ambiguity, being alert to the unknown, and gathering data to estimate risks are crucial to preserve evidence and save lives. Hence, in order to avoid fake facts and to provide sustainable solutions we need to pay attention to the various kinds of uncertainty. Producing high quality evidence is the solution, not the problem.