O 22 Rhagfyr, mae’r rheini sy’n eithriadol o agored i niwed yn glinigol wedi cael eu cynghori na ddylent fynd i'r gwaith na'r ysgol y tu allan i'r cartref mwyach ac y dylent aros gartref gymaint â phosibl. Gwnaed y newid hwn yng nghyd-destun y twf esbonyddol yn nifer yr achosion o’r coronafeirws, ynghyd â’r amrywiolyn newydd o’r coronafeirws y canfuwyd ei fod yn cylchredeg yng Nghymru. Mae'r cyngor hwn ar waith tan 31 Mawrth.
From 22ndDecember the advice to the clinically extremely vulnerable has been that they should no longer attend work or school outside the home and should remain at home as much as possible. This change was made in the context of cases of coronavirus rising exponentially, alongside the identification of a new variant of coronavirus circulating in Wales. This advice is in place until 31stMarch.