The mysterious condition was first published in the fall of 2016 when a staffer at the U.S. embassy in Cuba experienced headaches, hearing loss, memory problems, and other symptoms.
Since then a constant stream of Americans on every continent except Antarctica has experienced the same odd symptoms - the most recent being reported in Vienna.
On Monday, the Biden Administration stated it had been looking into what the government suspects were 'directed' radio frequency attacks on US diplomats in the Austrian capital, and a department spokesperson explained that the incidents were a 'top priority' for Secretary of State Antony Blinken.
'We are vigorously investigating reports of possible unexplained health incidents among the U.S. Embassy Vienna community or wherever they are reported,' the spokesperson explained.
About two dozen US intelligence officers, diplomats, and other officials in Vienna have reported symptoms comparable to those of Havana Syndrome, which creates dizziness, headaches, and hearing loss, since President Joe Biden took office in January, the New Yorker reported Friday.
The reports in Vienna, as well as a previously undisclosed report that a US diplomat's term in Germany was cut short by the unidentified illness, brings the whole number of cases of the syndrome to 200, according to NBC.
Among them, about half of all cases included CIA officers or their relatives, about 60 have been connected to Department of Defense workers or relatives, and roughly 50 involved State Department personnel, the outlet reported.
Potential cases among Americans abroad have now been reported on every continent except Antarctica and in the past year including reports of more than one American stationed in Kyrgyzstan with a baby, having undergone comparable symptoms.
Furthermore, two cases were detected close to the White House in recent months, with the US government now fast-tracking sensor technology to attempt and recognize the microwave technology and track it down.
The suspected directed-energy attacks have baffled US investigators who are working to learn who and what is causing them since they first started in Cuba five years ago.
In May reports emerged that some US officials suspect Russia's infamous foreign intelligence agency - the GRU - could be the culprit.
A U.S. military officer based in a nation with a large Russian presence further says he felt like his head was going to explode during one incident where he was found to have been near a G.R.U. vehicle.
And Politico reported that government investigators are studying a suspected attack on US personnel in Miami last year.