The Eastern Health Board has started an investigation how 66 children in Newbridge, Co Kildare, were given the wrong vaccine at school last week.
The children, aged five and six, who are pupils at St Conleth's Primary School, received an injection which was, different from the one their parents had consented to. They were given a three in ones booster vaccine containing whooping cough, diphtheria and tetanus instead of a two in one injection without whooping cough.
The inquiry is being conducted by the Southern Health Board's director of public health, Dr Elizabeth Keane, and the community care manager with the Midland Health Board, Mr John Kincaid.