The introduction of mandatory hotel quarantine has led to no new Covid variants being detected in Ireland.
HPSC figures show the number of cases of the Brazilian and South African strains reached 30 at the end of March.
But that figure fell to zero in the last week of April, when the system was in place.
An update to the hotel quarantine list has seen Nepal and Anguilla added - with 11 countries, including Austria and Italy, removed.
Sinn Fein's health spokesperson David Cullinane says more changes can be expected: