Boris Johnson, the former Prime Minister of the United Kingdom, struggled to understand much of the science during his time in office, according to testimony by Patrick Vallance, his former chief scientific advisor. Vallance testified at the UK’s public inquiry into the COVID-19 pandemic on Monday, stating that he and others encountered repeated difficulties in getting Johnson to comprehend scientific evidence and advice. However, Vallance also noted that leaders in many countries faced similar problems in understanding scientific evidence and advice. Despite these challenges, it is important for policymakers to listen to and consider scientific evidence when making decisions that affect public health.