of the 171,812 positive cases that were eligible for follow-up, 171,195 (99.6%) were reached and asked to provide details of their recent contacts
o blith y 171,812 o achosion positif a oedd yn gymwys i'w holrhain, cyrhaeddwyd 171,195 (99.6%) a gofyn iddynt ddarparu manylion y bobl y maent wedi dod i gysylltiad â nhw yn ddiweddar