A Rare Case of Toxic Myositis Associated with Influenza Vaccination

The influenza vaccine is one of the most commonly administered vaccines worldwide, with a high safety profile. However, rare cases of serious adverse events have been reported in the literature. We report a 77-year-old male who presented with progressive weakness in the lower extremities shortly after receiving the Influenza vaccine. He was diagnosed with myositis involving the paraspinal and bilateral lower extremity muscles. He received treatment with high-dose steroids and taper with full recovery of his muscle weakness. Although the exact causal mechanism between the vaccine and the patient's myositis could not be established, surveillance for such rare adverse events can provide data for future vaccine safety improvement. Due to well-known benefits of the Influenza vaccine that far exceed the potential adverse effects, we strongly encourage the readers to continue their vaccine practices as per CDC guidelines.