What is Havana Syndrome? Symptoms of illness affecting US diplomats, what causes it - and are there UK cases

Intelligence experts believe around 1,000 US diplomats and spies hit by a mystery illness known as Havana Syndrome could have been targeted by electromagnetic energy pulses.

A US intelligence report by a panel of expert scientists said the combination of symptoms could not be easily explained by known health or environmental factors among a subset of victims.

The report did not specify how many people have been affected by the syndrome, but cases have been reported in Russia, Austria,China, Tajikistan and some African countries.

There has been debate over whether the symptoms affecting US staff around the world were caused by a device, or were psychological in nature.

The latest report says the symptoms are “genuine and compelling” and could, in some cases, have been caused by a concealed device, but the investigation was not tasked with identifying who might be responsible.

What is Havana Syndrome?

Havana syndrome first emerged in Cuba in 2016 when US intelligence officers and diploats began complaining of unusual symptoms.

The claims were largely dismissed within government initially, but in the last year have started to be taken more seriously with US officials encouraged to report any symptoms.

This led to at least a thousand cases being reported around the world.

What are the symptoms?

The symptoms of Havana Syndrome have been found to range in severity and include pain and ringing in the ears, headaches, and balance and memory problems. Some victims have also suffered long-term brain damage.

In the recent US report, the panel of scientists identified four “core characteristics” of the syndrome. These include:

• Sudden onset of sound or pressure in one ear or one side of the head
• Vertigo
• Loss of balance 
• Ear pain and a “strong sense of locality and directionality” with no other explanations

What causes the symptoms?

Intelligence experts have said that “pulse electromagnetic energy, particularly in the radio frequency range, plausibly explains” the ear pain, vertigo and other symptoms of those who are suffering with the mysterious illness.

The US report examined the plausibility of five potential causes to determine whether a concealed device could be responsible for the symptoms. These included:

• acoustic signals
• chemical and biological agents
• ionizing radiation
• natural and environmental factors
• radiofrequency and other electromagnetic energy 

In a summary of the findings, published on Wednesday, the panel said the symptoms of the syndrome were “diverse and may be caused by multiple mechanisms”, but a subset of them “cannot be easily explained by known environmental or medical conditions”.

The report said: “Pulsed electromagnetic energy, particularly in the radiofrequency range, plausibly explains the core characteristics, although information gaps exist.

“There are several plausible pathways involving various forms of pulsed electromagnetic energy, each with its own requirements, limitations, and unknowns.

“For all the pathways, sources exist that could generate the required stimulus, are concealable, and have moderate power requirements.

The panel said electromagnetic pulsed energy could be directed at a target “through air for tens to hundreds of meters, and with some loss, through most building materials”, although a large portion of information on pulsed electromagnetic energy was redacted in the published report.

The executive summary said that ultrasound energy was also a plausible explanation for the symptoms but only in situations where the source was close to the target.

The report said that psychosocial factors, including work demands, stress and depression, could not alone account for the core symptoms of Havana Syndrome, but could have made them worse.

On Tuesday (1 February), President Joe Biden named a senior National Security Council official to coordinate his government’s response to possible incidents related to Havana Syndrome.

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