of the 18,444 positive cases that were eligible for follow-up, 15,306 (83.0%) were reached and asked to provide details of their recent contacts
o blith y 18,444 o achosion positif a oedd yn gymwys i'w holrhain, cyrhaeddwyd 15,306 (83.0%) a gofyn iddynt ddarparu manylion y bobl y maent wedi dod i gysylltiad â nhw yn ddiweddar