Persistent pruritic subcutaneous nodules at injection sites and other delayed type hypersensitivity reactions to aluminium adsorbed vaccines in Irish children: a case series.

Vaccination in childhood is among the most effective public health measures and is an essential component of the battle to prevent serious infection. Many vaccines use adjuvants to enhance immunogenicity and generate immunological memory. Currently 4 of the 5 inactivated vaccines (6in1: DTaP, HiB, Polio, HBV, Men B, PCV, Men C) in the Irish Primary Immunisation schedule use aluminium (Al) salts as an adjuvant. Persistent pruritic subcutaneous nodules (vaccination granulomas) can occur following the use of Al-adsorbed vaccines. Hypersensitivity to Al has been reported as a sequela of such reactions.1 The occurrence of this type of reaction can lead to the withdrawal of consent for future vaccines.1 Little is known about the experience among Irish children.