Havana Syndrome: Effects, Technology, Actors Coming Together?

A once-skeptical Norwegian scientist has provided first-hand evidence that pulsed high-power microwaves can cause the neurological symptoms in human beings associated with the Havana Syndrome. The Washington Post recently revealed that in 2024, using a microwave generator built secretly in Norway, he irradiated himself and began to show signs of the affliction.

The term Havana Syndrome was coined after diplomats and employees at the U.S. Embassy in Havana, Cuba, were attacked at their residences in 2016, reporting symptoms ranging from sounds and headaches to dizziness, loss of balance, pressure in the head, ear pain, and disturbed vision. Long term effects include a range of neurological, cognitive, and vestibular illnesses in some cases accompanied by brain damage. Subsequently, similar illnesses were reported around the globe, especially among American embassy or consulate personnel. Cases were also reportedly identified as early as 2014. A 2020 National Academies report identified pulsed high-power microwaves (HPM) as a plausible cause of the observed symptoms.

Short-duration, high-power pulses such as these can produce non-thermal effects of the type described by an IC Experts Panel convened by the Director of National Intelligence and the Deputy Director of the CIA: thermo-acoustic effects, direct electrical coupling, and resonant disruption. The effect involves the wireless transfer of energy from the microwave source to a thin layer of tissue in the brain where pulse-heating transforms the microwave energy into either acoustic energy of mechanical waves or electrical waves in the brain. Each might produce the symptoms of Havana Syndrome.

The experiments with mice involved scientists from the Institute of High-Current Electronics. This institute and the Institute of Electrophysics in Ekaterinburg are both world-class centers of excellence for the development of compact generators of high-power microwaves. Coincidentally, both were founded by Gennadiy Mesyats, once Vice-President of the Russian Academy of Sciences. Of the technologies investigated by these organizations, one line of technology development embodied in the SINUS and RADAN devices scales from very large systems to desktop-size units. Although it wasn’t used in the mice experiments, we believe this technology with its distinctively compact internal configuration is a prime candidate to be modified or scaled to a device that could produce the symptoms of Havana Syndrome.

The question of who is mounting these attacks was addressed in a March 2024 collaboration outside the IC between The Insider, Der Spiegel, and CBS’ 60 Minutes. They presented an extraordinary investigation of the actions of the Russian military intelligence Unit 29155. This unit is notorious for assassination and sabotage actions including the 2018 near-fatal chemical attack on Sergei Skripal and his daughter in the UK. The Insider, for example, based its analysis on painstaking review of phone and travel records as well as victim interviews to place unit personnel at or plausibly near claimed attacks.

One claimed sufferer of a 2021 attack in Tbilisi, Georgia, identified her assailant to The Insider as the son of the Unit 29155 leader. 60 Minutes learned from two U.S. officials that the identified assailant was in Tbilisi around the time of the attack. Another claimed victim from a 2014 attack in Frankfurt also identified another member of Unit 29155 as a prowler in his neighborhood around the days of the attack.

Two features of the attacks stand out. One is an apparent bias in the choice of targets toward those who had expertise or operational experience in Russia or former Soviet states. The other is that many of the attacks took place over relatively short range, when the victims were in hotel rooms or apartments, or in houses near streets allowing vehicles to get close. Under these conditions, wall plugs or vehicles could provide electrical power, reducing the size of the pulsed microwave generator even more.

Despite the evidence, the official U.S. government position continues to be defined by the initial Intelligence Community Assessment (ICA) published in January 2022 and twice updated in unclassified versions released in March 2023 and January 2025. Remarkably, even after the 2024 acquisition of a candidate pulsed microwave device and the self-test by the Norwegian scientist, the 2025 update revealed a split within the IC on the question of whether a foreign actor possesses the capability to produce the observed effects on people. Five IC elements still judged it very unlikely. Only two elements switched positions since the first assessment, now holding very finely divided judgments. One believed it likely that a foreign actor possesses an anti-personnel capability that can create Havana Syndrome symptoms. The other judged it a roughly even chance that a foreign actor possesses a capability that could have caused at least some Havana Syndrome events. According to the Washington Post, the two outlier agencies were the National Security Agency and the Army’s National Ground Intelligence Center.

Beyond the question of capability, in the 2025 update, six IC agencies still concluded that the involvement of a foreign actor in producing the syndrome is either very unlikely or unlikely (one other element abstained). Among the six, confidence in their judgments ranged from high-to-moderate to moderate. The reasoning included “investigations have not linked any foreign actor to any reported incident;” “intelligence reporting the IC has collected since March 2023 point away from foreign actors being responsible;” and the lack of “compelling intelligence reporting that ties a foreign actor to any specific event reported as” Havana Syndrome. According to the Washington Post, U.S. officials appear to rely, at least in part, on intelligence collection against adversaries’ conversations expressing surprise at the reported incidents and denial of their own participation.

There are those closer to the issue who are highly critical of the IC positions on Havana Syndrome. David Relman, who chaired the IC Experts Panel investigating possible causes for Havana Syndrome, noted that the IC issued its original report weeks before the Experts Panel had produced its own report. According to the Washington Post, Relman commented that the intelligence agencies “essentially ignored” the Panel’s work, adding that the agencies, especially the CIA, “had developed a very firm set of conclusions, world view that caused them I think to become dug in.”

In an interview with 60 Minutes, Greg Edgreen who investigated the Havana Syndrome for the Defense Intelligence Agency from 2021 to 2023 while a Lieutenant Colonel, expressed his belief that the bar for proof in the overall investigation was being set too high.

In December 2024, the Subcommittee on the Central Intelligence Agency of the House Permanent Select Committee on Intelligence (HPSCI) published its interim findings following an investigation of the Intelligence Community’s effort to get to the bottom of the Havana Syndrome problem. Noting the lack of cooperation from the IC, two of the Subcommittee findings relate directly to the IC’s efforts to that point. The first: “The ICA on AHIs [Anomalous Health Incidents] lacked analytic integrity and was highly irregular, hindering the Subcommittee’s trust in the IC’s process and conclusions.” The second: “The IC’s response to AHIs has likely impeded collection.”

Unclassified information appears to contradict the IC denial of foreign capability or involvement. Without seeing the full classified IC Assessment, it is impossible to determine what additional information in the assessment undermines the information released or produced by unclassified sources. We note that the tone of the presentation suggests a very conservative analytical approach, setting a very high bar, as described by Greg Edgreen. Analysis that “points away” from someone, but, after years, points to no one, is problematic. We ask how agencies hold to the judgment that there is no identified capability to produce the Havana Syndrome even after the U.S. obtains a possible device and Norway reports Havana Symptoms produced by a scientist who irradiated himself.

Dr. Swegle is a private consultant and former Department of Energy national laboratory employee.

Dr. Benford is the retired President of Microwave Sciences. With Dr. Swegle, he is coauthor of High Power Microwaves, just published in its fourth edition.