And both the United States and the Austrian authorities have confirmed they are investigating the incidents, which come at a time when Cuba is in the spotlight as a result of widespread pro-democracy protests there. So-called Havana syndrome refers to what the US government suspects are “directed” radio frequency attacks on US diplomats which resulted in various neurological ailments, and which first emerged in the Cuban capital in 2016.
US Secretary of State Andrew Blinken confirmed last month a wide-ranging review in who or what caused the illnesses was underway, and it now appears the attacks have spread to the Austrian capital.
The New Yorker magazine said on Friday that since US President Joe Biden took office in January, roughly two dozen US intelligence officers, diplomats and other officials in Vienna have reported symptoms similar to those of Havana syndrome, which would make the city the second-biggest hotspot after Havana.
Austria’s Foreign Ministry said in a statement: “We take these reports very seriously and in line with our role as host state we are working with the US authorities on jointly getting to the bottom of this.
“The safety of diplomats posted to Vienna and their families is of the utmost importance to us.”
A State Department spokesperson said the United States was “vigorously investigating” the reported cases.
Once a centre of Cold War intrigue, Vienna is home to several UN agencies and the Organization for Security and Cooperation in Europe, meaning bigger countries including the United States and Russia often have three ambassadors and a large diplomatic presence there.
US diplomats in China reported similar health issues a year later, as did CIA agents working to counter Russian covert operations.
Furthermore, the Trump investigation was revived in 2020 after two suspected directed-energy attacks in London and Northern Virginia on White House staffers in 2019, with two female staff apparently targeted.
Victims report lingering headaches, loss of hearing and balance, and in some instances, permanent brain damage.
In 2018, Jeanne Shaheen, Democrat Senator for New Hampshire, said: “These injuries, and subsequent treatment by the US government, have been a living nightmare for these dedicated public servants and their families.
“It’s obvious how a US adversary would have much to gain from the disorder, distress and division that has followed.”
Speaking to Express.co.uk in 2018, Dr Ian McLoughlin, Professor of Computing at the University of Kent, said he was unwilling to speculate about whether countries were developing sonic weapons – but added: “The technology is there.”
He added: “We have the tools to detect these sounds in the lab but that’s not where something like this would happen.
“It would be very difficult to detect.”
He speculated that the incidences of Havana syndrome thus far detected were the results of attempted surveillance attempts rather than targeted attacks.
Widespread protests across Cuba began on July 11, driven by shortages of food and medicine as well as the Cuban government’s response to the COVID-19 pandemic.