of the 174,706 positive cases that were eligible for follow-up, 174,172 (99.7%) were reached and asked to provide details of their recent contacts
o blith y 174,706 o achosion positif a oedd yn gymwys i'w holrhain, cyrhaeddwyd 174,172 (99.7%) a gofyn iddynt ddarparu manylion y bobl y maent wedi dod i gysylltiad â nhw yn ddiweddar