of the 17,104 positive cases that were eligible for follow-up, 15,348 (89.7%) were reached and asked to provide details of their recent contacts
o blith y 17,104 o achosion positif a oedd yn gymwys i'w holrhain, cyrhaeddwyd 15,348 (89.7%) a gofyn iddynt ddarparu manylion y bobl y maent wedi dod i gysylltiad â nhw yn ddiweddar