n light of the potential risk posed by SARS-CoV-2 variants, in January 2021 WHO organized an ad hoc consultation to discuss the development of an R&D agenda in response to existing and emerging SARS-CoV-2 variants. The key objectives were to identify the critical research questions related to variants and agree on a research approach to address them. Six breakout groups covered a range of specific issues related to COVID-19 variants: Epidemiology and mathematical modelling; evolutionary biology; animal models; assays and diagnostics; clinical management and therapeutics; and vaccines. This report is a summary of presentations and panel discussions.