United States government agencies are continuing investigations into the cause of Anomalous Health Incidents (AHIs), a series of health events reported by American diplomats, intelligence officers, and other personnel serving worldwide. The incidents, first reported in large numbers in Havana, Cuba, in 2016 and now commonly known as “Havana syndrome,” remain officially unexplained and are the subject of ongoing debate within the U.S. government.
The first cluster of cases emerged among staff at the U.S. Embassy in Havana. Affected individuals reported a range of symptoms, often with a sudden onset, including dizziness, severe headaches, tinnitus, cognitive difficulties, and sensations of pressure or vibration. Since then, hundreds of similar incidents have been reported by U.S. personnel and their families in various locations, including China, Austria, Germany, and Washington, D.C.
In response, the U.S. government has undertaken multiple investigations to determine the cause and origin of the incidents. In February 2022, a panel of scientific experts convened by the Director of National Intelligence released a report concluding that the signs and symptoms of AHIs were “genuine and compelling.” The panel stated that for a subset of cases, pulsed electromagnetic energy “plausibly explains” the core symptoms.
However, a subsequent assessment released in March 2023 by the National Intelligence Council, which incorporated findings from seven U.S. intelligence agencies, stated it was “very unlikely” that a foreign adversary was responsible. That report suggested that the majority of reported AHIs could be attributed to pre-existing medical conditions, conventional illnesses, or environmental factors. It did not find credible evidence linking the incidents to a foreign adversary or a specific weapon.
The differing conclusions have fueled a persistent debate. Some officials who reported AHI symptoms, along with their legal representatives, have maintained that the incidents are the result of targeted attacks. Marc Polymeropoulos, a former senior CIA officer, publicly stated he experienced debilitating symptoms during a trip to Moscow in 2017. He was later diagnosed with a mild traumatic brain injury and qualified for compensation under the 2021 Helping American Victims Afflicted by Neurological Attacks (HAVANA) Act, which provides financial and medical support to affected government employees.
David Relman, a Stanford professor who chaired the 2022 scientific panel, has stated that his panel’s review of classified information and patient records led him to believe that a subset of cases was “most plausibly explained by exposure to pulsed microwave energy.”
Some scientists and sociologists have offered alternative explanations, suggesting that the symptoms could be psychogenic and related to high-stress work environments. Proponents of this view have pointed to the lack of a definitive “smoking gun,” such as a recovered device or a clear intelligence intercept.
CIA Director William Burns has met with affected personnel and described the incidents as a top priority for the agency. In a statement referenced in a 2024 book on the subject, Burns said that any suggestion of a “cover-up” by the CIA was “simply not true” and that the agency conducted “a rigorous effort” to investigate the matter.
The U.S. government has not issued a final, unified conclusion on the cause of all reported AHIs. The debate continues among intelligence agencies, scientific experts, and affected personnel as official reviews of the incidents proceed.
, known as Havana syndrome, reported by personnel worldwide. Reports offer varying conclusions on potential causes and origin.){kind=link}