Severe Adverse Reaction to Measles Vaccine Due to Homozygous Mutation in the IFNAR2 Gene: A Case Report and Literature Review.

Receiving the measles vaccination is crucial for controlling the disease and preventing severe complications. However, adverse reactions can occur in individuals with inborn errors of immunity. This case report details a severe reaction to the measles vaccine in a ten-month-old female with a homozygous mutation in the IFNAR2 gene, leading to immunodeficiency-45. Following vaccination, she developed viremia, meningoencephalitis, and multi-organ failure. Genetic analysis identified a Variant of Uncertain Significance (VUS) in the IFNAR2 gene, which is essential for type I interferon (IFN-I) signaling. This case highlights the importance of incorporating genetic screening into vaccination programs for individuals at risk. It demonstrates the complex relationship between genetic mutations and the immune responses to the vaccines.