of the 20,636 positive cases that were eligible for follow-up, 15,326 (74.3%) were reached and asked to provide details of their recent contacts
o blith y 20,636 o achosion positif a oedd yn gymwys i'w holrhain, cyrhaeddwyd 15,326 (74.3%) a gofyn iddynt ddarparu manylion y bobl y maent wedi dod i gysylltiad â nhw yn ddiweddar