Havana syndrome: a scoping review of the existing literature.

Since 2016, numerous American and Canadian diplomats and secret (intelligence) agents in Cuba, China, and other places in the world have experienced an abrupt onset of unusual clinical symptoms including, tinnitus, visual problems, vertigo, and cognitive difficulties, after they encountered strange sounds; this has been called "Havana syndrome" (HS). MEDLINE, Scopus, and Ovid databases from 2016 until 24 September 2021 were systematically searched for the related published manuscripts. The following search strategy was implemented: "Havana syndrome" OR "Neurological Symptoms and US Diplomats". The primary search yielded 120 publications. Only five original studies and 18 non-original articles were considered to be relevant. While these studies provided a constellation of signs and symptoms for HS, none provided a good level of evidence. In conclusion, Havana syndrome is a nonspecific neurological illness with an unidentified causative factor(s), an acute phase of auditory-vestibular symptoms and a chronic phase of nonspecific neurobehavioral symptoms. This syndrome should be considered and investigated as a health concern, and not as a political issue.