The COVID-19 pandemic of 2020 has caused high levels of mortality and continues to threaten the lives of the global population. The pandemic has amounted to a “once in a lifetime” event for humanity and has affected it across its different sectors of existence: health, education, economy and environment, among others. The pandemic continues to threaten job prospects for millions of people and has resulted in widespread economic turmoil. It has also led to the cancellation of numerous conferences and research fieldwork and to closed offices across the globe.

As the scientific community grapples with how to respond to the massive and rapidly evolving crisis, the volume of research literature that has been published in relation to the outbreak has expanded rapidly. Simultaneously, efforts to synthesize this growing evidence base have begun, both through ongoing traditional approaches to independent systematic reviews, and through rapid and living systematic reviews. Rapid systematic reviews provide in a timely way the evidence needed to inform policy-making under urgent circumstances. On the other hand, living systematic reviews ensure that any evidence synthesis is up to date with the latest evidence.

As the volume of evidence increases and decision-makers and scientists grapple with the rapidly expanding evidence base, many research groups are volunteering to support these efforts by using online collaborative tools and virtual workspaces, in an effort to support continued working during challenging times and also to help identify, map, and synthesize research as it emerges.

This work faces a suite of challenges because of the often closed nature of science. The major challenges are the duplication of efforts (leading to research waste), inefficiency in conducting research, and missed opportunities to address important questions. Open science principles present an opportunity to address these challenges in the context of the COVID-19 pandemic. They would also ensure that the research in the field is more collaborative, transparent, and rigorous. This article argues in favour of, and illustrates how researchers should be, applying the principles of Open Science to the field of evidence synthesis, a concept the authors refer to as “Open Synthesis”. They use the COVID-19 pandemic as a case in point to highlight the potential significant benefits of openness to the research, policy, and practice communities.