It is still not too late for these groups to become vaccinated, although the window of opportunity for vaccination to be effective during this flu season year is now becoming smaller.
Nid yw'n rhy hwyr i'r grwpiau hyn i gael eu brechu, er bod diwedd y cyfnod pryd y gall y brechiad fod yn effeithiol ar gyfer y tymor ffliw hwn yn prysur agosáu.