of the 509,785 positive cases that were eligible for follow-up, 481,496 (94.5%) were reached and asked to provide details of their recent contacts
o blith y 509,785 o achosion positif a oedd yn gymwys i'w holrhain, cyrhaeddwyd 481,496 (94.5%) a gofyn iddynt ddarparu manylion y bobl y maent wedi dod i gysylltiad â nhw yn ddiweddar