Vaccine safety in children with genetically confirmed mitochondrial disease.

We here explore adverse events following immunization (AEFI) in children with mitochondrial disease (MD) recruited from two expertise centers in Austria (SALK) and The Netherlands (RUMC). Parents completed a questionnaire on the type of immunizations received and AEFI in a post-vaccination exposure period of seven days. 95 individuals were invited to this study, of whom 30 (median age 13.4 years) participated. Together these individuals had received 376 immunizations with a median of 12 vaccinations each. In 316 of 376 (84 %) vaccinations no AEFI occurred, 22 patients (73 %) never experienced any AEFI. Eight patients experienced 76 AEFI after 60 vaccinations, these were mild (redness (n = 9) /pain at injection site (n = 21), fever (n = 44), gastrointestinal complaints (n = 2)). None had a metabolic deterioration or seizures, no patient was admitted to the hospital. Although our data is limited by the small sample size, this may aid in discussing responsible immunization decisions with parents.