of the 21,074 positive cases that were eligible for follow-up, 16,601 (78.8%) were reached and asked to provide details of their recent contacts
o blith y 21,074 o achosion positif a oedd yn gymwys i'w holrhain, cyrhaeddwyd 16,601 (78.8%) a gofyn iddynt ddarparu manylion y bobl y maent wedi dod i gysylltiad â nhw yn ddiweddar