We report SARS-CoV-2 antibody responses following vaccination in a UK cohort of AML and HR-MDS patients all receiving, or having recently completed SACT, and stratified by prior SARS-CoV-2 infection. (D) Seroconversion rates in patients with no previous SARS-CoV-2 infection, after one and two doses of vaccine (paired predose, post first dose and second dose) in all patients. Encouraging seroconversion rates to SARS-CoV-2 vaccination in acute myeloid leukaemia (AML) and myelodysplastic syndrome (MDS) patients have been reported in large cohort studies1-4; however, the majority of these patients were not receiving active systemic anti-cancer therapy (SACT) and its impact on vaccine responses remains to be fully elucidated. [Extracted from the article]