Autonomic nervous system changes are some of the most reported symptoms after vaccination for COVID-19. A new study by Leys et al. finds that dysautonomia, a disorder affecting the autonomic nervous system, differs in prevalence and severity between two important cohorts. Adjusting for confounders, autonomic nervous system issues are more severe in patients who had an adverse event subsequent to vaccination for COVID-19, than patients who were diagnosed with dysautonomia after infection with SAR