Vaccines currently routinely recommended to the general population in the U.S.* have not been shown to cause brachial neuritis.
The 2012 report by the Institute of Medicine (IOM), now called the National Academy of Medicine (NAM), found no relevant studies of quality in the literature assessing an association between vaccination and brachial neuritis 1. No relevant studies of quality have been published since this report.
Proposed Biological Mechanism
Although the etiology of brachial neuritis is still uncertain, it is generally considered to be an immune-mediated inflammatory reaction against nerve fibers in the brachial plexus. One possible mechanism is activation of the complement system, in which a cascade of proteolysis and successive release of cytokines functions to amplify the immune response but can damage host cells if not properly regulated. Other mechanisms for such a reaction include anti-peripheral nerve myelin antibodies or T cells 2.
The IOM concluded that there was no mechanistic evidence for an association between vaccination and brachial neuritis, as the publications reviewed provided no evidence beyond a temporal association 1.
* These conclusions do not necessarily consider vaccines recommended only for special populations in the United States such as Yellow Fever vaccine (international travelers) or Smallpox vaccine (military personnel), or vaccines no longer recommended to the public such as the Janssen (J&J) COVID-19 vaccine.
1. Institute of Medicine. In: Stratton K, Ford A, Rusch E, Clayton EW, eds. Adverse Effects of Vaccines: Evidence and Causality. Washington (DC): National Academies Press (US); 2012.
2. Shaikh MF, Baqai TJ, Tahir H. Acute brachial neuritis following influenza vaccination. BMJ Case Rep 2012;2012.