of the 16,567 positive cases that were eligible for follow-up, 14,850 (89.6%) were reached and asked to provide details of their recent contacts
o blith y 16,567 o achosion positif a oedd yn gymwys i'w holrhain, cyrhaeddwyd 14,850 (89.6%) a gofyn iddynt ddarparu manylion y bobl y maent wedi dod i gysylltiad â nhw yn ddiweddar