Bydd angen dau ddos o'r brechlyn, gyda chyfnod o bedair i 12 wythnos rhwng y ddau. Mae hyn yn wahanol i'r cyngor blaenorol ar gyfer y ddau frechlyn, sef cyfnod o bedair wythnos rhwng y ddau ddos, gan fod y Cydbwyllgor Brechu ac Imiwneiddio (JCVI) wedi argymell y dylid sicrhau mai'r flaenoriaeth gyntaf yw cynnig dos cyntaf y brechlyn i gynifer o bobl â phosibl yn y grwpiau blaenoriaeth uchaf.
Two doses will be needed, with an interval of between four and 12 weeks between doses. This is a change from previous advice for both vaccines of a four week gap between doses, as the Joint Committee on Vaccination and Immunisation (JCVI) has recommended that as many people as possible in the top priority groups should sequentially be offered a first vaccine dose as the initial priority.