As we have learnt more about the virus, its variants and how effective the vaccines are, it has become clearer that managing the virus is likely to be a long term challenge.
Wrth inni ddysgu mwy am y feirws, ei amrywiolion a pha mor effeithiol yw'r brechlynnau, daw'n gliriach bod rheoli'r feirws yn debygol o fod yn her hirdymor.