of the 18,305 positive cases that were eligible for follow-up, 13,771 (75.2%) were reached and asked to provide details of their recent contacts
o blith y 18,305 o achosion positif a oedd yn gymwys i'w holrhain, cyrhaeddwyd 13,771 (75.2%) a gofyn iddynt ddarparu manylion y bobl y maent wedi dod i gysylltiad â nhw yn ddiweddar