Why were so few randomized trials of public health and social measures conducted during the COVID-19 pandemic? The Norwegian experience

Background Few randomized trials of public health and social measures were carried out during the COVID-19 pandemic. We report on the major barriers we faced when we tried to run such trials. Methods We reviewed all randomized trials proposed and initiated by the Centre for Epidemic Interventions Research in Norway during the COVID-19 pandemic. Results Of the 18 proposed trials, 11 trials were not implemented. One of the key legal and ethical barriers to conducting the trials was the Norwegian Health Research Act, which demands informed consent from all participants who are exposed to an intervention. A lack of sufficient political support was also a challenge, as was unpredictability, due to shifting disease incidence and changing recommendations from the authorities. Conclusion Strengthening the evidence base for public health and social measures in pandemics will require political and public understanding and support and a legal framework that allows for the conduct of such trials.