Mass hysteria. Only affected US diplomats. Heavily disproven. It was these idiot Fairfax County types that realized hearing crickets could get them a medical retirement.
https://mronline.org/2022/01/29/havana-syndrome-the-u-s-s-monumental-hoax/
Even the CIA says it was fake. But they want those medical retirements.
The article does not discuss the cases that were happening outside of Cuba.
Other countries include China, India, Switzerland, France etc.
Here is an article about some Europe cases:
https://www.bbc.com/news/world-us-canada-59986297
I consider this matter unsolved but I would not rule out side effects from our own high tech listening devices inside our own embassies.
If the technologies are secret and compartmentalized it would be kinda difficult for .gov to fess up....