Revaccination following suspected vaccine triggered hypersensitivity reactions: experience of a tertiary care centre

Abstract

Introduction and objectives: Suspected hypersensitivity reactions (HRs) associated with vaccines are frequently reported, but confirmed cases of vaccine-triggered HRs are rare. Suspected HRs should be distinguished from actual HRs. The aims of this study are to identify the rate of actual vaccine-triggered hypersensitivity in patients who were referred to the paediatric allergy clinic due to a suspected HR and to explore the rate of revaccination in a real clinical setting. Materials and methods: A retrospective study was performed with a group of preschool children who were evaluated by skin and/or provocation tests (PTs) for the suspected HRs following vaccination. Results: A total of 26 paediatric patients (61.5% male; median age 9 months) with a previous history of suspected vaccine-triggered HR were included. In this group, 69.2% and 38.5% of the patients had a pre-existing atopic disease and an immediate reaction (emerging <1 hour after vaccine administration), respectively. Skin rash was the most frequent clinical presentation (96.1%). Vaccine-triggered anaphylaxis was reported in six patients (23.1%). Measles-mumps-rubella was the most frequently suspected vaccine causing HRs. The skin test positivity with the suspected vaccine was 4%, whereas PTs revealed no reaction after reimmunisation in 76.9% (20/26) of the study participants tested. Conclusions: Most incidents of skin rashes after immunisation are not suggestive of actual HRs. The results in the current study showed that the majority of the patients presenting with suspected HRs tolerated revaccination, including those with a previous history of suspected anaphylaxis. Revaccination of these patients is safe with adequate precautions. It is absolutely essential to be equipped for the management of anaphylaxis.