Rapid review methods more challenging during COVID-19: commentary with a focus on 8 knowledge synthesis steps

What is new?Key findings•Guidance is available on the conduct of rapid reviews. However, the COVID-19 pandemic has created several unique challenges.•Challenges to the conduct of rapid reviews include the urgency of the request from decision-maker organizations, identification of and access to sources of evidence for inclusion in the rapid reviews, extrapolation of results from indirect evidence, and dissemination of results widely.What this adds to what is known?•There is a need for coordination of efforts internationally to reduce the risk of duplication, and to effectively use global collective evidence synthesis resources.•We outline several methodological challenges to the conduct of rapid reviews that have become apparent during the COVID-19 pandemic using an 8-step framework that follows the knowledge synthesis process.What is the implication and what should change now?•We offer several suggestions to help address the methodological challenges encountered during the conduct of rapid reviews on COVID-19, as well as future research. Key findings•Guidance is available on the conduct of rapid reviews. However, the COVID-19 pandemic has created several unique challenges.•Challenges to the conduct of rapid reviews include the urgency of the request from decision-maker organizations, identification of and access to sources of evidence for inclusion in the rapid reviews, extrapolation of results from indirect evidence, and dissemination of results widely.What this adds to what is known?•There is a need for coordination of efforts internationally to reduce the risk of duplication, and to effectively use global collective evidence synthesis resources.•We outline several methodological challenges to the conduct of rapid reviews that have become apparent during the COVID-19 pandemic using an 8-step framework that follows the knowledge synthesis process.What is the implication and what should change now?•We offer several suggestions to help address the methodological challenges encountered during the conduct of rapid reviews on COVID-19, as well as future research.