Be careful when using preprint servers for medical research reports 16 Shares The coronavirus pandemic posed unprecedented challenges and forced a shift towards an accelerated digital transformation. The COVID-19 public health emergency focused attention on timely dissemination and reporting of research findings, resulting in the rapid growth of preprint platforms. Preprint servers like medRxiv, bioRxiv, ChemRxiv, arXiv, and ResearchSquare received attention for sharing preliminary research during the COVID-19 pandemic. Preprint servers facilitate rapid dissemination, seek the establishment of priority, and solicit feedback and collaborations. I am a supporter of preprint platforms and of open discussions of preliminary scholarly findings. A JAMA research letter reports that clinical journals with the highest impact factor are broadly supportive of considering research preprints for publication. The number of page views, median altmetric attention scores, number of news outlets citing were higher for preprints. These later published preprints also showed trends towards a greater engagement on social media platforms like Twitter.