Havana Syndrome

Havana syndrome is a set of medical signs and symptoms reported by United States and Canadian embassy staff in Cuba dating back to late 2016 as well as subsequently in some other countries, including the United States.[11][12][13]

In 2017, President Donald Trump accused Cuba of perpetrating unspecified attacks causing these symptoms. The U.S. reduced staff at their embassy to a minimum in response.[14] 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 Russia′s covert operations around the world.[15][16]

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.[17][18] While there is no expert consensus on the cause of the symptoms,[13] a co-author of the JAMA study considered microwave weapons to be “a main suspect” for the phenomenon.[3] A U.S. National Academies of Sciences, Engineering, and Medicine expert committee concluded in December 2019 that microwave energy (specifically, directed pulsed RF energy) “appears to be the most plausible mechanism in explaining these cases among those that the committee considered” but that “each possible cause remains speculative.”

In August 2017, reports began surfacing that American and Canadian[20] diplomatic personnel in Cuba had experienced unusual, unexplained health problems dating back to late 2016.[21][22] The number of American citizens experiencing symptoms was 26 as of June 2018.[23]


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.[24]

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.[25] 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,[26] and declared that they were not blaming the Cuban government, but would not say who was to blame.[27] Affected individuals described symptoms such as hearing loss, memory loss, and nausea.[26] Speculation centered around a sonic weapon,[28] with some researchers pointing to infrasound as a possible cause.[29]

In August 2017, the United States expelled two Cuban diplomats in response to the illnesses.[21] 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.[30] In October 2017, U.S. President Donald Trump said that “I do believe Cuba’s responsible. I do believe that”,[31] going on to say “And it’s a very unusual attack, as you know. But I do believe Cuba is responsible.”[14]

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.[32]

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.[33] 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.[11]

In January 2018, at the direction of Secretary of State Rex Tillerson, the Department of State convened an Accountability Review Board,[34] which is “an internal State Department mechanism to review security incidents involving diplomatic personnel.”[35] Retired United States Ambassador to Libya Peter Bodde was chosen to lead the board.[35]

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.[36]

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.[37] In February 2019, several Canadian diplomats sued the Canadian government, arguing that it failed to protect them or promptly address serious health concerns.[38][39] 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.[40] In a November 2019 statement, Global Affairs Canada said, “We continue to investigate the potential causes of the unusual health symptoms.”[40]

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.[41][42]

The Cuban government offered to cooperate with the U.S. in an investigation of the incidents.[43] 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.[44]

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.”[5][45] 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.”[5][45] 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.”[5] 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.[17][18] 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.[17][18] 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.”[18]

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.[3] 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.[46] Neuroscientist Allan H. Frey, for whom the Frey effect is named, considered the microwave theory to be viable.[3]

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 “Overall, directed pulsed RF energy … appears to be the most plausible mechanism in explaining these cases among those that the committee considered” but that “each possible cause remains speculative” and that “the report should not be viewed as conclusive”.[19][2][4] Chaired by David Relman, the committee included Linda Birnbaum, Ronald Brookmeyer, Caroline BuckeeJoseph FinsDavid A. Whelan, and others.[4] The panel stated that a lack of information (such as medical testing data about affected persons) limited what it could conclude about the plausible explanations for the phenomenon.[4][10]

Some scientists, including physicist Peter Zimmerman, bioengineers Kenneth R. Foster and Andrei G. Pakhomov, and UCLA neurologist Robert Baloh, consider the microwave hypothesis to be implausible, with Baloh calling the National Academies conclusion “science fiction”.[9][10]

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;[47][48] cricket noises,[49][50] and exposure to neurotoxic pesticides.[8][51] Early speculation of an acoustic or sonic cause was later determined to be unfounded.[46] Some had suggested that the symptoms represented episodes of mass hysteria,[7] but the 2018 JAMA researchers considered a “wholly psychogenic or psychosomatic cause” to be very unlikely, given the physical evidence of brain trauma.[18] 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.[52]


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.[47][48][53]

U.S. personnel in Cuba made sound recordings which they released to the Associated Press. In January 2019, biologists Alexander L. Stubbs of the University of California, Berkeley and Fernando Montealegre-Z of the University of Lincoln analyzed these recordings and 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.[54][49] 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.”[49] This conclusion was comparable to a 2017 hypothesis from Cuban scientists that the sound on the same recording is from Jamaican field crickets.[54][55][50][56] 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.[57]

Psychogenic origin[edit]

Sociologist Robert Bartholomew and Robert Baloh, among others, argue against the microwave theory and propose that the syndrome is an example of a mass psychogenic illness.[58][6][59][60][61][7][62][63][55] Bartholomew expressed incredulity at State Department medical director Dr. Charles Rosenfarb’s testimony that the department had “all but ruled out ‘mass hysteria” as a cause.[60][64][65] In support of his stance, Bartholomew has noted that: (1) bioengineer Kenneth Foster claims that any link between the microwave Frey effect and Havana syndrome is nonsensical, (2) in many of the cases the sounds reported by diplomats have been identified as the sound of insects, (3) the kinds of symptoms that have been reported represent common patient complaints, and (4) the NAS report failed to reference evidence that the pattern of spread of the outbreaks is consistent with a psychogenic illness explanation.[6] However, Ragini Verma of the University of Pennsylvania Perlman School of Medicine, who was the co-lead author of the 2019 JAMA study,[45] considered a “wholly psychogenic or psychosomatic cause” to be very unlikely, given the researchers’ findings.[18]

The National Academies committee sought evidence “that psychological and social factors may have caused or contributed to symptoms reported by DOS [Department of State] personnel,” including Bartholomew and Baloh’s suggestion that mass psychogenic illness could be the cause of symptoms.[4]:26, 28 The committee, however, wrote that “the likelihood of mass psychogenic illness as an explanation for patients’ symptoms had to be established from sufficient evidence” and “could not be inferred merely by the absence of other causal mechanisms or the lack of definitive structural injuries.”[4]:26 The committee concluded that, because it lacked patient-level psychological or psychiatric data, it “could not make a determination about the presence or absence of delusional disorder as a cause for the distinct acute symptoms in any affected persons,” but that “delusional disorders could not explain the full range of symptoms reported by the entire group of patients.”[4]:26 Noting that the “significant variability and clinical heterogeneity of the illnesses affecting DOS personnel leave open the possibility of multiple causal factors, over time and place, both for individual cases and for the population,” the committee held that “psychological and social factors,” like other mechanisms examined, could potentially “exacerbate other forms of pathology” and contribute to morbidity “in some of the cases, especially for individuals with chronic symptoms.”[4]:28 The committee also concluded that the “acute initial, sudden-onset, distinct and unusual symptoms and signs described in some affected DOS personnel … cannot be ascribed to psychological and social factors in the absence of patient-level data.”[4]:28

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.[8][51][66] The study concluded that other possible causes could not be ruled out.[8]

The 2020 National Academies study found that that it was unlikely that “acute high-level exposure to OPs and/or pyrethroids contributed” to the illnesses, due to a lack of evidence of exposures to those pesticides or clinical histories consistent with such exposure.[4]:23 However, the National Academies study committee “could not rule out the possibility, although slight, that exposure to insecticides, particularly OPs, increased susceptibility to the triggering factor(s) that caused the Embassy personnel cases.”[4]:23 The National Academies study committee 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.[4]:23–24

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.[15][67][68] Another incident had previously been reported by a USAID employee at the U.S. Embassy in TashkentUzbekistan, in September 2017; the employee’s report was discounted by the U.S. State Department.[69]

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.[70][71] 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.”[67] In June 2018, the State Department announced that a task force had been assembled to investigate the reports[72] 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.[73] 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.”[74]

In and around Washington D.C.[edit]

In 2019, a White House official reported experiencing debilitating symptoms while walking her dog in a Virginia suburb of Washington; the incident was publicly reported in 2020.[13] In November 2020, a similar incident was reported on The Ellipse, a lawn adjacent to the south side of the White House.[13][75] Both incidents were similar to those that were reported to have struck dozens of U.S. personnel overseas, including CIA and State Department personnel.[13] Federal agencies investigated the incident at The Ellipse, and Defense Department officials briefed members of the Senate Armed Services Committee and House Armed Services Committee in April 2021.[13]

Investigators told members of Congress that they had not been able to determine the cause of the events or who was responsible, although officials indicated that it was possible that Russia or China were responsible.[13]

Theories regarding culprit[edit]

The U.S. State Department said in 2021 that its “investigation is ongoing and is a high priority” and that it had “not yet determined a cause or culprit.”[76] Many current and former U.S. officials, however, identified Russia as likely responsible.[76] This view was shared by CIA analysts on Russia, State Department officials, outside science experts, and several of victims,[16] who noted Russia’s “history with weapons that cause brain injuries” (such as the Cold War-era “Moscow Signal” at the American embassy in Moscow and a 2014 NSA report that raised suspicions that Russia used a microwave weapon to target a person’s living quarters, causing nervous system damage) and Russian’s interest in disrupting cooperation between the U.S. and China and Cuba.[16] The U.S. diplomats stationed in China and Cuba who reported ailments were working to increase cooperation with those countries, and some CIA analysts voiced suspicion Russia thus sought to derail their work.[16]

Trump administration and lapses in initial investigation[edit]

In 2020, the New York Times reported that U.S. diplomats and intelligence officers, including senior leaders, had clashed with Trump administration appointees, including CIA director Gina Haspel and State Department leaders, over the nature and causes of the suspected attacks.[16] A Times investigation found that the State Department had “produced inconsistent assessments of patients and events, ignored outside medical diagnoses and withheld basic information from Congress.”[16] Despite the general view within the U.S. government that Russia was responsible, two U.S. officials told the Times that Haspel was not convinced of Russia’s responsibility, or even whether an attack occurred.[16]

A 2018 State Department report was declassified, and posted on the George Washington University‘s National Security Archive, after Freedom of Information Act litigation brought by the James Madison Project. The documents indicate that the initial State Department handling of the attacks was botched. Peter Kornbluh of the National Security Archive noted that the 2018 report concluded that the department’s “initial investigation assessment of what was going on” was marred by chaos, disorganization, and excessive secrecy.[16] In 2021, sources familiar with the various ongoing investigations told CNN that a primary obstacle to progress by the U.S. government in investigating the syndrome was a lack of interagency coordination between the CIA, FBI, Centers for Disease Control and Prevention, and State Department, which conducted separate and “largely siloed” investigations.[76] The limited coordination among the varying agencies was based in part of “the highly classified nature of some details and the privacy restrictions of health records, and that has hampered progress.”[76]

An U.S. Office of Special Counsel investigation resulted in an April 2020 determination that there was “a substantial likelihood of wrongdoing” by State Department leadership.[16] Mark Lenzi, who was a State Department diplomatic security officer stationed in Guangzhou, accused the department of a “deliberate, high-level cover-up” and of failing to protect their employees.[16] Marc Polymeropoulos, a 26-year CIA veteran, who retired in 2019, similarly felt betrayed by CIA leadership, accusing the agency of failing to respond appropriately to a vertigo-inducing attack in Moscow in December 2017 (which Polymeropoulos called “the most terrifying experience of my life” and more frightening than experiences in Iraq and Afghanistan).[76] Polymeropoulos fought with the CIA for years to obtain specialized medical treatment, after the agency cast doubt on the similarities between the symptoms he experienced and those suffered by the diplomats in Havana.[76] Polymeropoulos was ultimately diagnosed at the U.S. government’s Walter Reed Medical Center with traumatic brain injury; attorney Mark Zaid, who represented almost a dozen clients who had become ill from similar attacks, said that Polymeropoulos was the only one of his clients who had received treatment at Walter Reed, with others obtaining treatment only from personal doctors or academic medical centers.[76]

Defense Department and CIA task forces[edit]

Near the end of the Trump administration, the Defense Department established a task force to investigate reports of attacks on DoD personnel abroad.[13] The DoD established the task force partly due to frustration over what DoD officials considered to be a sluggish and lackluster response by the CIA and Department of State.[13] Christopher C. Miller, who was acting defense secretary at the time, said in 2021 that, “I knew CIA and Department of State were not taking this shit seriously and we wanted to shame them into it by establishing our task force.”[13] Miller said that he began to consider the reports of mysterious symptoms to be a high priority in December 2020, after he conducted an interview with a person with major combat experience who detailed symptoms.[13]

In December 2020, the CIA established a task force to investigate the attacks.[13][76] The agency set up the task force after continued reports of debilitating attacks against CIA officers in various places around the world.[76] The CIA expanded its investigation under Director William Joseph Burns, who took office in 2021.[13] In March 2021, the State Department appointed a senior official to oversee the department’s response to the attacks.[13]

After the reports of the incident at The Ellipse nearby the White House in Washington, Defense Department investigators briefed members of Congress, even though it occurred within the U.S.; this was because the DoD investigation was more advanced than the FBI or the Intelligence Community investigation