Human T-cell leukaemia virus type 1 (HTLV-1) is a human retrovirus that causes adult T-cell lymphoma and HTLV-associated myelopathy. In this issue, Rosadas et al. use data from a recent WHO report to describe how blood banks test for HTLV-1 and how this testing contributes to public health surveillance for the virus. Commentary on: Rosadas et al. HTLV-1 screening of blood donations: we are systematically missing opportunities. Br J Haematol 2023 (Online ahead of print). doi: 10.1111/bjh.18988.