of the 167,886 positive cases that were eligible for follow-up, 167,226 (99.6%) were reached and asked to provide details of their recent contacts
o blith y 167,886 o achosion positif a oedd yn gymwys i'w holrhain, cyrhaeddwyd 167,226 (99.6%) a gofyn iddynt ddarparu manylion y bobl y maent wedi dod i gysylltiad â nhw yn ddiweddar