of the 23,558 positive cases that were eligible for follow-up, 18,322 (77.8%) were reached and asked to provide details of their recent contacts
o blith y 23,558 o achosion positif a oedd yn gymwys i'w holrhain, cyrhaeddwyd 18,322 (77.8%) a gofyn iddynt ddarparu manylion y bobl y maent wedi dod i gysylltiad â nhw yn ddiweddar