BRACHIAL NEURITIS FROM THE MRNA SARS-COV-2 AND INFLUENZA VACCINES

INTRODUCTION: Rare neurologic side effects have been reported with the mRNA SARS-CoV-2 and Influenza vaccines. We report a case of brachial neuritis after the second mRNA SARS-CoV-2 which recurred after a subsequent influenza vaccine. CASE DESCRIPTION: 29 year-old male received his first mRNA SARS-CoV-2 n his left arm. He had isolated persistent mild pain at the injection site. This prompted him to receive his second vaccine in his right arm three weeks later. Within a few hours of the injection, he had fever, nausea, and severe pain near his left tricep and olecranon process. The severe pain improved somewhat after treatment with opiates. In the next two weeks, he developed left arm weakness, numbness in his left fourth and fifth digits, with eventual muscle wasting of his left trapezius. The weakness was profound and prevented him from performing activities of daily living. An EMG confirmed the diagnosis of left brachial neuritis. He was treated with oral steroids, physical therapy, and improved within several months with residual mild paresthesias. He received the influenza vaccine approximately six months later in his right arm. The exact symptoms returned in his left arm, though milder, and self-resolved after a week. DISCUSSION: This is a most unusual reaction to the mRNA SARS-CoV-2 vaccine which recurred after a different vaccine was given, albeit, with much less severe and persistent symptoms. It is important to be aware of rare neurologic complications of vaccination and the possibility of recurrence with subsequent unrelated vaccines.