of the 28,004 positive cases that were eligible for follow-up, 22,673 (81.0%) were reached and asked to provide details of their recent contacts
o blith y 28,004 o achosion positif a oedd yn gymwys i'w holrhain, cyrhaeddwyd 22,673 (81.0%) a gofyn iddynt ddarparu manylion y bobl y maent wedi dod i gysylltiad â nhw yn ddiweddar