Neurologic Complications With Vaccines: What We Know, What We Don't, and What We Should Do.

Over the previous half century, vaccines have shaped human life by eradicating or nearly eradicating infections that were once a major cause of morbidity and mortality. The number of infections for which vaccines are now available has steadily increased. The types of vaccines have evolved over the years from crude extracts to more refined messenger RNA or protein-based vaccines. With these well-defined manufacturing processes, the safety profile has also improved. Despite such measures, vaccines are not without side effects, including those that affect the nervous system. Numerous case reports and case series point to these possibilities. These issues have gathered much attention during the current mass vaccination against severe acute respiratory syndrome coronavirus 2 and have resulted in some members of the public raising concerns about vaccine safety. The vaccine manufacturers have legal protection against vaccine side effects; however, there are active and passive surveillance programs put in place by the Center for Disease Control and Prevention, the US Food and Drug Administration, the World Health Organization, and the European Union. Action is needed that brings together manufactures, healthcare agencies, clinical and bench scientists, and legislatures on a global platform to investigate vaccine-related neurologic adverse events and develop ways to prevent and treat them.