Vice President Kamala Harris’ departure for Vietnam was delayed by several hours this afternoon after her office was informed by the US embassy in Hanoi, Vietnam, of a “report of a recent possible anomalous health incident.”
That term is the way that the government usually refers to the mysterious Havana syndrome that has sickened hundreds of US officials over the past few years.
Havana syndrome has no known cause, though the most likely hypothesis is a form of direct energy attack that sometimes causes brain damage. Attacks of this nature have previously forced some U.S. officials into early retirement. Here’s what we know so far.