of the 27,851 positive cases that were eligible for follow-up, 24,350 (87.4%) were reached and asked to provide details of their recent contacts
o blith y 27,851 o achosion positif a oedd yn gymwys i'w holrhain, cyrhaeddwyd 24,350 (87.4%) a gofyn iddynt ddarparu manylion y bobl y maent wedi dod i gysylltiad â nhw yn ddiweddar