The Technical Advisory Group published a paper in February 2021 Technical Advisory Group: Long-COVID which sets out what we know about long COVID and what we still need to understand.
Cyhoeddodd y Grŵp Cyngor Technegol bapur ym mis Chwefror 2021 Y Grŵp Cyngor Technegol: COVID hi r sy'n nodi'r hyn rydym yn ei wybod am COVID hir a'r hyn y mae angen i ni ei ddeall o hyd.