Batches of a polio vaccine under investigation for possible links with mad cow disease were issued after their expiry date, the Minister for Health and Children said yesterday.
Mr Martin said the discovery came to light following an examination of immunisation records by GPs and health boards following his announcement last month that the vaccine contained serum from a donor who had been diagnosed with variant CJD.
He said the preliminary advice received was that the effectiveness of the vaccine was reduced if administered after its expiry date. As a result, he said, some children would require further doses of vaccine.
The Immunisation Advisory Committee of the Royal College of Physicians of Ireland met to consider the issue last Thursday. It is due to brief the Department of Health's deputy chief medical officer today. Mr Martin said he had also sought advice from the Irish Medicines Board.
A spokeswoman for the Minister said it had yet to be established how many children would be recalled for further doses. It is understood only a small number, in one health board area, had been identified to date.
In a statement, the Minister said the health boards had been instructed to urgently conduct a detailed examination of their records. Following this, parents of any children affected will be contacted via the health boards or their GPs.
Whether new mechanisms needed to be developed to guard against future possible use of out-of-date vaccines would be considered by a new National Immunisation Steering Committee, the Minister added. The committee, to be established by the health board's chief executive officers, will also review the protocols for the administration of vaccines.
The polio vaccine in question was administered to an estimated 50,000-60,000 children between January 15th, 1998, and January 30th, 1999. The Minister has stressed that the risk arising from it relating to CJD was "almost certainly" zero.
Polio vaccine is given to children at the ages of two, four and six months, and a booster immunisation is given at primary school entry age. Adults travelling to regions such as China, sub-Saharan Africa and parts of Asia are also vaccinated against polio.
