Policy makers must act on incomplete evidence in responding to COVID-19

Reducing the transmission of Coronavirus disease 2019 (COVID‐19) is a global priority. Toward this end, public health officials and politicians across the world have been seeking scientific expertise to guide policy. In response, investigators have rushed to share new results on preprint servers, and journals have expedited editorial and peer review processes to publish them. The urgency to define the relevant knowledge base in preventing,...