"Rydym yn gweld cynnydd cyflym yn nifer yr achosion o Covid-19 a achosir gan omicron ledled Cymru. Mae'r rhan fwyaf o'r rhain ymysg pobl iau a chredwn y byddent wedi cael eu dal cyn y Nadolig.
“We are seeing a rapid rise in Covid-19 cases caused by omicron all over Wales. The majority of these are in younger people and we believe they would have been contracted before Christmas.