A whooping cough vaccination programme for expectant mothers is to be extended for the next five years.
Health Minister Edwin Poots said the immunisation, offered to pregnant women between 28 weeks and 38 weeks, provided the best protection for newborn babies.
The vaccination was introduced in September 2012 following a national whooping cough (pertussis) outbreak. It aims to boost the short-term immunity passed on by women to their babies while they are still in the womb.
Dr Richard Smithson, consultant in health protection at the Public Health Agency, said it had been "highly effective" in protecting infants.
He said: "Babies born to women vaccinated at least a week before delivery generally had a 91% reduced risk of becoming ill with whooping cough in their first weeks of life, compared with babies whose mothers had not been vaccinated."