The number of Covid-19 cases related to overseas travel has increased "very sharply" recently, according to Deputy Chief Medical Officer Ronan Glynn.
He said over 800 such infections were reported in the last fortnight alone, three quarters of them in people aged under 35 years old.
In a series of posts on Twitter, he said it was "strongly advised" that people should only travel on the basis of their vaccination status or immunity (having recovered from Covid). "Public health colleagues are reporting an increasing number of cases in people who have travelled overseas very shortly after they have completed their vaccine course," he said. "It is advised that people should not consider themselves fully vaccinated until two weeks after their