Havana Syndrome is back in the spotlight: Is it linked to a secret Pentagon device?

Nearly ten years after American diplomats in Cuba first began reporting unexplained neurological symptoms, Havana Syndrome is one again back under the lens.

The development follows revelations that the United States Defense Department has been testing a mysterious device believed by some investigators to be capable of triggering the condition, reported CNN this week.

What we know about a secret Pentagon device

According to CNN, the Department of Defense provided funding for Homeland Security Investigations (HSI) — a division of the Department of Homeland Security — to acquire a device through an undercover operation during the final phase of the Biden administration.

Officials paid what sources described as “eight figures” for the equipment, amounting to tens of millions of dollars.

The device has been under evaluation for more than a year. One person familiar with the matter said it emits pulsed radio waves, a type of energy that has been repeatedly suggested as a possible cause of Havana Syndrome.

The same source noted that while the equipment is not fully Russian-made, it contains Russian components.

Despite the scale of the investment, the technology’s connection to the illness remains contested.

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Some officials continue to question whether a portable system could realistically produce the injuries reported by victims. Others argue that the findings are serious enough to warrant continued investigation.

The device is reportedly compact enough to be carried in a backpack, raising concerns about how easily such technology could be transported and potentially used without detection.

Officials are also worried about the possibility that similar devices may exist beyond a single country’s control, meaning more than one nation could possess the capability to harm US personnel overseas.

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Lawmakers were briefed on the matter late last year, with the House and Senate Intelligence Committees receiving updates that included references to the device and the ongoing testing process.

HSI has a history of working with the US military on investigations related to the spread of sensitive technology abroad. A former Homeland Security official described such cases as “the single biggest collaboration point between HSI and the US military.”

In past conflicts, when American forces encountered US-made technology in places like Afghanistan or Iraq, HSI would be called in to investigate how those components ended up there.

What remains unclear is how the US government learned about the existence of the device in the first place. For years, both intelligence agencies and medical researchers have struggled to determine what caused the symptoms now known as anomalous health incidents (AHIs).

What is Havana Syndrome and where it has occurred

Havana Syndrome first entered public awareness in late 2016, when multiple US diplomats stationed in Cuba began reporting unusual health problems. The symptoms included dizziness, intense headaches, ringing in the ears, memory difficulties and a sensation of pressure in the head.

While the earliest widely reported cases were in Havana, some accounts suggest similar incidents may have occurred as early as 2014.

Over the following years, reports of comparable symptoms emerged from dozens of countries. US officials now estimate that at least 1,500 suspected cases have been recorded across 96 nations.

Countries where incidents have been reported include China, India, Austria, Vietnam, France, Switzerland and Lithuania. The Wall Street Journal reported in 2022 that American officials in Paris and Geneva were affected.

Several high-profile cases brought the issue into the spotlight:

• A Pentagon official said they experienced symptoms during a Nato summit in Lithuania in 2023.

• In 2022, then-US Vice President Kamala Harris postponed a visit to Hanoi after reports of an anomalous health incident.

• Two National Security Council staff members were affected in November 2020, with one reporting symptoms the day after the US presidential election and another a week later.

• A White House official told GQ in 2020 that she began experiencing symptoms while walking her dog.

The condition has not only affected diplomats but also intelligence officers, military personnel and, in some cases, their family members.

There is no single medical definition for Havana Syndrome. However, reports over the years have identified a consistent group of symptoms commonly described by those affected. These include:

• Ear-popping sensations

• Vertigo

• Severe, pounding headaches

• Nausea

• A piercing or directional noise

• A feeling of pressure in the head

Some victims have described symptoms that resemble traumatic brain injury, leading to concerns about possible long-term neurological damage.

To better understand the condition, researchers at the National Institutes of Health conducted MRI scans on 81 federal employees and their family members who reported hearing unusual sounds followed by cognitive symptoms.

The study, published in JAMA in 2024, found no significant differences between the brain structures of these individuals and those of a control group.

“It is possible that individuals with an [anomalous health incident] may be experiencing the results of an event that led to their symptoms, but the injury did not produce the long-term neuroimaging changes that are typically observed after severe trauma or stroke. We hope these results will alleviate concerns about AHI being associated with severe neurodegenerative changes in the brain,” said Carlo Pierpaoli, the study’s lead author, at the time.

Other research efforts have also produced inconclusive results, leaving medical experts divided over whether Havana Syndrome causes measurable brain damage. Some scientists have suggested that the symptoms could be linked to environmental exposure, neurological conditions, or even collective psychological stress.

Mitchell Valdés-Sosa, a senior researcher at Cuba’s Center for Neuroscience, told the Associated Press in 2024 that the symptoms may result from a variety of medical issues rather than “mysterious energy.”

Still, alternative explanations continue to be explored. Lawmakers have proposed that directed-energy weapons could be responsible. In 2022, an intelligence panel said that some cases could “plausibly” have been caused by “pulsed electromagnetic energy.”

CNN has reported that the device obtained by DHS emits pulsed radio waves, but researchers remain puzzled about how such technology could inflict the types of injuries described by victims.

What US govt assessments have been able to conclude

For years, the US intelligence community and the US Defense Department have investigated whether Havana Syndrome could be the result of hostile action by a foreign government.

In 2023, intelligence agencies publicly stated that it was unlikely the illness was caused by an adversary targeting American personnel worldwide.

A CIA official previously told The Washington Post, “We assess it is unlikely that a foreign actor, including Russia, is conducting a sustained, worldwide campaign harming US personnel with a weapon or mechanism.”

Earlier investigations had also considered the possibility that the symptoms resulted from natural causes rather than a weapon. CNN reported that investigators had not ruled out “a naturally occurring phenomenon rather than a weapon.”

Despite these conclusions, many victims remain unconvinced. Some current and former CIA officers have accused the agency of minimising the seriousness of the issue.

Evidence published in 2024 by The Insider, Der Spiegel and 60 Minutes suggested Russia’s GRU Unit 29155 may have been involved in some incidents. Moscow denied the claims.

“All this is nothing more than a baseless accusation, an unfounded accusation by the media,” Kremlin spokesperson Dmitry Peskov said, according to Russia’s TASS news agency.

Then-US Secretary of State Antony Blinken acknowledged in 2022 that the illness had puzzled US officials for years.

How victims have been affected

Victims have argued that intelligence agencies ignored key evidence and dismissed their experiences. Many say the lack of clear answers has compounded the personal and professional damage they suffered.

For those affected by Havana Syndrome, the discovery of the device represents a potential turning point. Marc Polymeropoulos, a former CIA officer who says he was injured during an incident in Moscow in 2017, told CNN, “If the [US government] has indeed uncovered such devices, then the CIA owes all the victims a f**king major and public apology for how we have been treated as pariahs.”

Some victims were forced into early retirement due to the severity of their symptoms. Others say the lack of recognition made it harder to receive proper medical care or compensation.

The absence of a clear definition for anomalous health incidents has also complicated diagnosis and treatment. In many cases, medical tests were conducted long after symptoms began, making it difficult to determine what physically occurred at the time of the incident.

Officials now face pressure to determine whether the technology represents a genuine threat and whether earlier assessments underestimated its significance.

With inputs from agencies