For employers that require COVID-19 vaccines, OSHA now considers any adverse reactions to be workplace injuries.
OSHA: "If you require your employees to be vaccinated as a condition of employment (i.e., for work-related reasons), then any adverse reaction to the COVID-19 vaccine is work-related...”
https://www.enr.com/articles/51691-osha-imposes-new-guidance-for-employer-required-covid-19-vaccines