Havana syndrome

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Havana syndrome
The Hotel Nacional in Havana is one of the locations where the syndrome occurred.[1]
SymptomsHearing strange grating noises, headache, hearing loss, memory loss, and nausea
CausesLikely caused by directed microwaves[2]

Havana syndrome is a set of medical signs and symptoms experienced by United States and Canadian embassy staff in Cuba. Beginning in August 2017, reports surfaced that American and Canadian diplomatic personnel in Cuba had suffered a variety of health problems, dating back to late 2016.[3][4]

The U.S. government accused Cuba of perpetrating unspecified attacks causing these symptoms. The U.S. reduced staff at their embassy to a minimum in response.[5] In 2018, U.S. diplomats in China reported problems similar to those reported in Cuba, as well as undercover CIA agents operating in other countries who were negotiating with those countries on ways to counter Russian covert operations around the world.[6][7]

Subsequent studies of the affected diplomats in Cuba, published in the journal JAMA in 2018, found evidence that the diplomats experienced some form of brain injury, but did not determine the cause of the injuries.[8][9] A co-author of the JAMA study considered microwave weapons to be "a main suspect" for the phenomenon.[10]

In December 2020, a study by an expert committee of the U.S. National Academies of Sciences, Engineering, and Medicine, commissioned by the State Department, released its report, concluding that "directed" microwave radiation was the likely cause of illnesses among American diplomats in Cuba and China.[2][11]



In August 2017, reports began surfacing that American and Canadian[12] diplomatic personnel in Cuba had experienced unusual, unexplained health problems dating back to late 2016.[13][14] The number of American citizens experiencing symptoms was 26 as of June 2018.[15]


The health problems typically had a sudden onset: the victim would suddenly begin hearing strange grating noises that they perceived as coming from a specific direction. Some of them experienced it as a pressure or a vibration; or as a sensation comparable to driving a car with the window partly rolled down. The duration of these noises ranged from 20 seconds to 30 minutes, and always happened while the diplomats were either at home or in hotel rooms. Other people nearby, family members and guests in neighboring rooms, did not report hearing anything.[16]

Impact on American diplomats[edit]

Some U.S. embassy individuals have experienced lasting health effects, including one unidentified diplomat who is said to now need a hearing aid.[17] The State Department declared that the health problems were either the result of an attack, or due to exposure to an as-yet-unknown device,[18] and declared that they were not blaming the Cuban government, but would not say who was to blame.[19] Affected individuals described symptoms such as hearing loss, memory loss, and nausea.[18] Speculation centered around a sonic weapon,[20] with some researchers pointing to infrasound as a possible cause.[21]

In August 2017, the United States expelled two Cuban diplomats in response to the illnesses.[13] In September, the U.S. State Department stated that it was removing non-essential staff from the US embassy, and warned U.S. citizens not to travel to Cuba.[22] In October 2017, U.S. President Donald Trump said that "I do believe Cuba's responsible. I do believe that",[23] going on to say "And it's a very unusual attack, as you know. But I do believe Cuba is responsible."[5]

On March 2, 2018, the U.S. State Department announced it would continue to staff its embassy in Havana at the minimum level required to perform "core diplomatic and consular functions" due to concerns about health attacks on staff. The embassy had been operating under "ordered departure status" since September, but the status was set to expire. This announcement served to extend the staff reductions indefinitely.[24]

U.S. government investigations[edit]

In January 2018, the Associated Press reported that a non-public FBI report found no evidence of an intentional sonic attack.[25] A November 2018 report in the New Yorker found that the FBI's investigation into the incidents was stymied by conflict with the CIA and the State Department; the CIA was reluctant to reveal, even to other U.S. government agencies, the identities of affected officers, because of the CIA's concern about possible leaks. Federal rules on the privacy of employee medical records also hindered the investigation.[3]

In January 2018, at the direction of Secretary of State Rex Tillerson, the Department of State convened an Accountability Review Board,[26] which is "an internal State Department mechanism to review security incidents involving diplomatic personnel."[27] Retired United States Ambassador to Libya Peter Bodde was chosen to lead the board.[27]

Impact on Canadian diplomats[edit]

In March 2018, MRI scans and other tests taken by a chief neurologist in Pittsburgh, on an unspecified number of Canadian diplomats showed evidence of brain damage that mirrored the injuries some of their American counterparts had faced. In spring of 2018, Global Affairs Canada ended family postings to Cuba and withdrew all staff with families. Several of the Canadians who were impacted in 2017 were reported to still be unable to resume their work due to the severity of their ailments. The fact that, as of February 2019, there was no knowledge of the cause of “Havana syndrome” had made it challenging for the RCMP to investigate.[28]

In 2019, the government of Canada announced that it was reducing its embassy staff in Havana after a 14th Canadian diplomat reported symptoms of Havana syndrome in late December 2018.[29] In February 2019, several Canadian diplomats sued the Canadian government, arguing that it failed to protect them or promptly address serious health concerns.[30][31] The government has sought to dismiss the suit, arguing in November 2019 that it was not negligent and did not breach its duties to its employees. In court filings, the government acknowledged that several of the 14 plaintiffs in the suit suffered from concussion-like symptoms, but said that no definitive cause or medical diagnosis had been ascertained.[32] In a November 2019 statement, Global Affairs Canada said, "We continue to investigate the potential causes of the unusual health symptoms."[32]

Cuban government reactions[edit]

After the incident was made public, the Cuban Foreign Minister accused the U.S. of lying about the incident and denied Cuban involvement in the health problems experienced by diplomats or knowledge of their cause.[33][34]

The Cuban government offered to cooperate with the U.S. in an investigation of the incidents.[35] It employed about 2000 scientists and law enforcement officers who interviewed 300 neighbors of diplomats, examined two hotels, and also medically examined non-diplomats who could have been exposed. NBC reported that Cuban officials stated that they analyzed air and soil samples, and considered a range of toxic chemicals. They also examined the possibility that electromagnetic waves were to blame, and even looked into whether insects could be the culprit, but found nothing they could link to the claimed medical symptoms. The FBI and Cuban authorities met to discuss the situation; the Cubans stated that the U.S. neither agreed to share the diplomats' medical records with Cuban authorities nor allowed Cuban investigators access to U.S. diplomats' homes to conduct tests.[36]

Studies regarding injury[edit]

At the request of the U.S. government, University of Pennsylvania researchers examined 21 affected diplomats, and the preliminary results were published in the Journal of the American Medical Association (JAMA) in March 2018. The report "found no evidence of white matter tract abnormalities" in affected diplomats, beyond what might be seen in a control group of the same age, and described "a new syndrome in the diplomats that resembles persistent concussion."[37][38] While some of those affected recovered swiftly, others had symptoms lasting for months. The study concluded that "the diplomats appear to have sustained injury to widespread brain networks."[37][38] Some experts criticized the study, arguing that there was "no proof that any kind of energy source affected the diplomats, or even that an attack took place."[37] Subsequent study findings by the University of Pennsylvania team, published in July 2019, found that compared to a healthy control group, the diplomats who had reported injury had experienced brain trauma; advanced MRI scans (specifically res-fMRI, multimodal MRI, and diffusion MRI) revealed "differences in whole brain white matter volume, regional gray and white matter volume, cerebellar microstructural integrity, and functional connectivity in the auditory and visuospatial subnetworks" but found no differences in executive functions.[8][9] The study concluded that the U.S. government personnel had been physically injured in a way consistent with the symptoms that they described, but expressed no conclusion on the cause or source of the injury.[8][9] The New York Times reported: "Outside experts were divided on the study's conclusions. Some saw important new evidence; others say it is merely a first step toward an explanation, and difficult to interpret given the small number of patients."[9]

Theories regarding cause[edit]


In a 2018 interview, Douglas H. Smith, a co-author of the JAMA study, said that microwaves were "considered a main suspect" underlying the phenomenon.[10] A 2018 study published in the journal Neural Computation by Beatrice Alexandra Golomb rejected the idea that a sonic attack was the source of the symptoms, and concluded that the facts were consistent with pulsed radiofrequency/microwave radiation (RF/MW) exposure as the source of injury. Golomb wrote that (1) the nature of the noises reported by the diplomats was consistent with sounds caused by pulsed RF/MW via the Frey effect; (2) the signs and symptoms reported by the diplomats matched symptoms from RF/MW exposure (problems with sleep, cognition, vision, balance, speech; headaches; sensations of pressure or vibration; nosebleeds; brain injury and brain swelling); (3) "oxidative stress provides a documented mechanism of RF/MW injury compatible with reported signs and symptoms"; and (4) in the past, the U.S. embassy in Moscow was subject to a microwave attack.[39] Neuroscientist Allan H. Frey, for whom the Frey effect is named, considered the microwave theory to be viable.[10] Some other scientists, including physicist Peter Zimmerman and bioengineer Kenneth R. Foster, disagreed, considering the microwave hypothesis to be implausible.[40] A 2018 study published in the journal Neural Computation identified pulsed radiofrequency/microwave radiation (RF/MW) exposure via the Frey effect as source of injury, and noted that a microwave attack against the U.S. embassy in Moscow has been historically documented.[39]

In December 2020, a 19-person committee of medical and scientific experts convened by the National Academies of Sciences, Engineering, and Medicine at the request of the State Department published a Consensus Study Report, An Assessment of Illness in U.S. Government Employees and Their Families at Overseas Embassies, based on its review of the incidents and injuries.[11][41] The report concluded that "Overall, directed pulsed RF (radio frequency) energy, especially in those with the distinct early manifestations, appears to be the most plausible mechanism in explaining these cases among those that the committee considered."[41][11]

Previously proposed causes[edit]

Prior to 2019, some researchers posited other possible causes for the injuries, including ultrasound via intermodulation distortion caused by malfunctioning or improperly placed Cuban surveillance equipment;[42][43] cricket noises,[44][45] and exposure to neurotoxic pesticides.[46][47] Early speculation of an acoustic or sonic cause was later determined to be unfounded.[39] Some had suggested that the symptoms represented episodes of mass hysteria,[48] but the 2018 JAMA researchers considered a "wholly psychogenic or psychosomatic cause" to be very unlikely, given the physical evidence of brain trauma.[9] The 2020 National Academies report "considered chemical exposures, infectious diseases and psychological issues as potential causes or aggravating factors of the injuries" but determined that these were not the likely cause of the injuries.[41]


In March 2018, Kevin Fu and a team of computer scientists at the University of Michigan reported in a study that ultrasound—specifically, intermodulation distortion from multiple inaudible ultrasonic signals—from malfunctioning or improperly placed Cuban surveillance equipment could have been the origin of the reported sounds.[42][43][49]

In January 2019, biologists Alexander L. Stubbs of the University of California, Berkeley and Fernando Montealegre-Z of the University of Lincoln analyzed a recording of a sound made by U.S. personnel in Cuba and released to the Associated Press. Stubbs and Montealegre-Z concluded that the sound was caused by the calling song of the Indies short-tailed cricket (Anurogryllus celerinictus) rather than a technological device. Stubbs and Montealegre-Z matched the song's "pulse repetition rate, power spectrum, pulse rate stability, and oscillations per pulse" to the recording.[50][44] Stubbs and Montealegre wrote that "Although the causes of the health problems reported by embassy personnel are beyond the scope of this paper and called for "more rigorous research into the source of these ailments, including the potential psychogenic effects, as well as possible physiological explanations unrelated to sonic attacks."[44] This conclusion was comparable to a 2017 hypothesis from Cuban scientists that the sound on the same recording is from Jamaican field crickets.[50][51][45][52] Reuters reported that JASON, a group of physicists and scientists who advise the U.S. government, determined that "a rare jungle cricket" was the cause of the sounds in Havana.[53]

Psychogenic origin[edit]

In 2017, 2018, and 2019 sociologist Robert Bartholomew[54][55][56] and some neurologists wrote that the attacks represent episodes of mass psychogenic illness.[48][57][58][51] However, the co-lead author of the 2019 study published in JAMA, Ragini Verma of the University of Pennsylvania Perlman School of Medicine, considered a "wholly psychogenic or psychosomatic cause" to be very unlikely, given the researchers' findings,[9] and State Department medical director Dr. Charles Rosenfarb testified that the department had "all but ruled out 'mass hysteria" as a cause.[55][59][60]

Pesticides or infectious agents[edit]

A 2019 study commissioned by Global Affairs Canada of 23 exposed Canadian diplomats, completed in May 2019, found "clinical, imaging, and biochemical evidence consistent with the hypothesis" that over-exposure to cholinesterase inhibitors (a class of neurotoxic pesticide) such as pyrethroids and organophosphates (OPs) as a cause of brain injury; the embassies and other places in Cuba had been sprayed frequently as an anti-Zika virus mosquito control measure.[46][47][61] The study concluded that other possible causes could not be ruled out.[46]

The 2020 National Academies study found that that it was unlikely that "acute high-level exposure to OPs and/or pyrethroid contributed" to the illnesses, due to a lack of evidence of exposures to those pesticides or clinical histories consistent with such exposure; however, "the committee could not rule out the possibility, although slight, that exposure to insecticides, particularly OPs, increases susceptibility to the triggering factors that caused the Embassy personnel cases."[11] The 2020 National Academies study also found it "highly unlikely" that an infectious disease (such as Zika virus, which was an epidemic in Cuba in 2016-17) caused the illnesses.[11]

Guangzhou, China[edit]

In early 2018, accusations similar to those reported by diplomats in Cuba began to be made by U.S. diplomats in China. The first incident reported by an American diplomat in China was in April 2018 at the Guangzhou consulate, the largest U.S. consulate in China. The employee reported that he had been experiencing symptoms since late 2017. Several individuals were taken to the United States for medical examination.[6][62][63] Another incident had previously been reported by a USAID employee at the U.S. Embassy in Tashkent, Uzbekistan, in September 2017; the employee's report was discounted by the U.S. State Department.[64]

Answering questions from the House Foreign Affairs Committee on May 23, 2018, Secretary of State Mike Pompeo confirmed that U.S. diplomatic staff in Guangzhou had reported symptoms "very similar" to, and "entirely consistent" with, those reported from Cuba.[65][66] On June 6, 2018, The New York Times reported that at least two additional U.S. diplomats stationed at the Guangzhou consulate had been evacuated from China, and reported that "it remains unclear whether the illnesses are the result of attacks at all. Other theories have included toxins, listening devices that accidentally emitted harmful sounds, or even mass hysteria."[62] In June 2018, the State Department announced that a task force had been assembled to investigate the reports[67] and expanded their health warning to all of mainland China amid reports some US diplomats outside of Guangzhou had experienced the same symptoms resembling a brain injury.[68] The warning told anyone who experienced "unusual acute auditory or sensory phenomena accompanied by unusual sounds or piercing noises" to "not attempt to locate their source."[69]

Theories regarding culprit[edit]

Several U.S. State Department employees who consider themselves victims, and some senior CIA Russian analysts, as well as some outside scientists believe Russia is the most likely culprit. Russia has been accused by the U.S. State Department of using directed microwaves in the past. During the Cold War, the U.S. accused Russia of directing a microwave signal at the American embassy in Moscow, and a 2014 NSA report raised suspicions that Russia used an energy weapon to "bathe a target’s living quarters in microwaves", which caused nervous system damage. The purported targets in the 2016-2018 events include undercover CIA agents who were working on ways to counter Russian covert operations. Also, the U.S. diplomats stationed in China and Cuba who reported ailments were working to increase cooperation with those countries. Some CIA analysts suspect Russia was trying to disrupt all those activities.[7]

The New York Times reported in October 2020 that CIA director Gina Haspel and State Department leaders were unconvinced[clarification needed] that Russia is responsible or even whether an attack occurred. However, some believe there is a high-level and deliberate cover-up by the Trump-led State Department after a U.S. Office of Special Counsel investigation "found a substantial likelihood of wrongdoing" by State.[7]

See also[edit]


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