ABC News, November 5, 2021:

“Secretary of State Antony Blinken on Friday detailed new efforts to investigate “Havana syndrome,” the mysterious health affliction affecting dozens of U.S. personnel first identified in Cuba and now including several countries.”

“Symptoms include headaches, dizziness, cognitive difficulties, tinnitus, vertigo and trouble with seeing, hearing or balancing. Many officials have suffered symptoms years after reporting an incident, while some have been diagnosed with traumatic brain injuries.”

“In an effort to learn more, Blinken confirmed Friday that the State Department has deployed new technology to U.S. missions around the world to help understand the cause.

‘The details I can provide on this are limited as well, but I can say that new technology is helping us more quickly and thoroughly evaluate a variety of potential causes of these incidents, and we’ve distributed across posts so that we can respond rapidly to new reports,’ he said.”  

(Conor Finnegan and Matt Seyler, “Blinken details new efforts to investigate ‘Havana syndrome,” ABC News, Nov 5, 2021)

In my opinion, the “Havana syndrome” is likely caused by exposure to microwave or radio frequency radiation (RFR) resulting in the onset of electromagnetic hypersensitivity (EHS) in exposed individuals who have greater sensitivity to RFR. Moreover, as I explained to the Daily Mail in December 2017 the symptoms may be caused by exposure to low-moderate intensity microwave radiation used for surveillance:

“The finding that the attacks led to perceptible changes in their brains is also one of several factors fueling growing skepticism that some kind of sonic weapon was involved. 

‘This makes me think the victims may have developed electromagnetic hypersensitivity (EHS) from exposure to electromagnetic fields in the embassy,’ Joel Moskowitz, a community health professor at the University of California, Berkeley, told Daily Mail Online. 

‘This happened during the Cold War to personnel stationed in the US embassy in Moscow when the Soviets were bombarding the embassy with microwaves to monitor oral communications in the ambassador’s office.'”

If my hypothesis is correct that a surveillance device is the source of exposure for the “Havana syndrome” rather than a weapon, and if only a minority of exposed individuals are susceptible to developing serious symptoms associated with EHS, then the extent of surveillance could be widespread, placing our nation’s secrets at risk.
William Broad of the New York Times interviewed me for a story on the “Havana syndrome” in September 2018. He dismissed my hypothesis that the effects observed in Havana were due to EHS and that the source of the exposure may have been microwave-based surveillance technology rather than weaponry.  In his article, he did not cite me or Dr. Beatrice Golomb, a colleague from UC San Diego whom he also interviewed who had published a paper on the Havana syndrome in which she hypothesized that it was caused by pulsed microwave radiation (see abstract below).
In October 2019, following up on a referral from Allan Frey (who pioneered the research on microwave hearing and blood-brain-barrier penetration), Dr. Thaddeus Thomas from the U.S. Army Research Laboratory (ARL) contacted me to learn about the science regarding health effects from RFR exposure. He informed me that the ARL was heading a joint military task force to determine whether an adversary had developed new weapon technology based on RFR. I shared with him the research on EHS. I cautioned him not to assume that the “attack” was a weapon as it could have been from microwave-based surveillance technology because health effects have been observed in many individuals who experienced relatively low levels of RFR exposure. Moreover, Russian surveillance was a prime explanation for similar incidents that occurred at the U.S. embassy in Moscow during the Cold War (aka “Moscow signal”).
BTW, the smallest microwave weapon I am aware of, the Silent Guardian active denial system, requires a 10,000 pound containerized system to generate a 30-kilowatt beam. The primary symptom is a burning sensation in the skin, not strange sounds.
In October 2021, pursuing the military weapon angle, Dr. Thomas and his colleagues published the following paper in the AAAS journal Science Advances.

Computational modeling investigation of pulsed high peak power microwaves and the potential for traumatic brain injury
Amy M Dagro, Justin W Wilkerson, Thaddeus P Thomas, Benjamin T Kalinosky, Jason A Payne. Computational modeling investigation of pulsed high peak power microwaves and the potential for traumatic brain injury. Sci Adv. 2021 Oct 29;7(44):eabd8405. doi: 10.1126/sciadv.abd8405.
Amy Dagro and Thaddeus Thomas are with the U.S. Army Research Laboratory, Aberdeen Proving Ground, MD; Benjamin Kalinosky is with General Dynamics Information Technology, JBSA Fort Sam Houston, San Antonio, TX; and Jason Payne is with U.S, Air Force Research Laboratory, 711th Human Performance Wing, Airman Systems Directorate, Bioeffects Division, Radio Frequency Bioeffects Branch, JBSA Fort Sam Houston, San Antonio, TX.

When considering safety standards for human exposure to radiofrequency (RF) and microwave energy, the dominant concerns pertain to a thermal effect. However, in the case of high-power pulsed RF/microwave energy, a rapid thermal expansion can lead to stress waves within the body. In this study, a computational model is used to estimate the temperature profile in the human brain resulting from exposure to various RF/microwave incident field parameters. The temperatures are subsequently used to simulate the resulting mechanical response of the brain. Our simulations show that, for certain extremely high-power microwave exposures (permissible by current safety standards), very high stresses may occur within the brain that may have implications for neuropathological effects. Although the required power densities are orders of magnitude larger than most real-world exposure conditions, they can be achieved with devices meant to emit high-power electromagnetic pulses in military and research applications.


“The bulk of scientific literature uses continuous waves and moderate field strengths (typical of real-life scenarios), with less emphasis on pulsed fields of very high peak strength that may occur with ultrawideband pulse generators or EM pulse simulators (4). It is worth investigating whether extremely high peak power sources applied with a slow repetition frequency, or low duty cycle, can induce injurious effects without thermal buildup greater than a few degrees Celsius.”

“With the exception of low intracranial absorption at 1400 MHz, the highest ratio of peak average intracranial SAR* to peak average skin SAR* occurs between 1 to 1.8 GHz.”

“The MAE, also referred to as “microwave hearing” or the “Frey effect” due to its discovery by Allan Frey in 1961 (7, 8), was initially observed when subjects standing up to hundreds of feet away from a radar transponder could hear an audible tonal noise (e.g., chirping, buzzing, or clicking). The scientific underpinnings of the MAE were controversial for the first several years (9–11). After more than a decade of investigations, it became generally accepted that the perceived sound is due to the cochlea detecting stress waves that result from a rapid temperature rise in tissues within the head due to pulsed RF/microwave exposure (11, 12).”

“Typically, relatively low-average powers and small temperature changes (10−6°C) are required to elicit the MAE (12). Although adverse health effects from the MAE have not been previously established, one study on rodents suggests that very high–peak power pulsed microwaves can result in cognitive deficits (13).”

“This study uses a two-simulation approach to investigate whether an HPM source could theoretically induce adverse mechanical responses within the brain.”

“This study has shown that, by applying a small temperature increase (<0.0005°C) in a very short amount of time (less than several microseconds), potentially injurious stress waves are created.”

“For frequencies between 400 MHz to 2 GHz, the IEEE C95.1 RF exposure guidelines limit the exposure reference limit (ERL) to fmhz/200 (W/m2) over an averaging time of 30 min. For 1-GHz exposures, the IEEE C95.1 ERL of 5 W/m2 over 30 min would equate to an average energy density of 9000 J/m2. Our computational model shows that, for sufficiently high incident power densities, a single pulse could potentially result in biologically meaningful pressures. For example, large pressures may occur following 1-GHz frequency, a pulse duration of 5 μs, and incident power densities of at least 1.5 × 107 W/m2. The energy density associated with such a pulse would be equal to PIN×τd or 75 J/m2 (significantly less than the ERL standard).”

“Note that the proposed HPM power densities in this study are extremely large and several orders of magnitude larger than power densities typically experienced by the public. As an illustrative example, at around 200 feet from a cell phone base station, a person will be exposed to a power density of only 0.001 mW/cm2 or less (36). This study establishes a testable hypothesis between potential neurocognitive effects and the thermoelastic mechanism from HPM systems. To date, however, adverse effects from HPM systems have not been established in the scientific literature.”

New Report Assesses Illnesses Among U.S. Government Personnel and Their Families at Overseas Embassies

News Release, National Academy of Sciences, Engineering, and Medicine, December 5, 2020

WASHINGTON — Government personnel and their families at the U.S. embassy in Havana, Cuba, in late 2016, and later at the U.S. consulate in Guangzhou, China, began suffering from a range of unusual — and in some cases suddenly occurring — symptoms such as a perceived loud noise, ear pain, intense head pressure or vibration, dizziness, visual problems, and cognitive difficulties, and many still continue to experience these or other health problems.  As part of its effort to ascertain potential causes of the illnesses, inform government employees more effectively about health risks at posts abroad, and determine best medical practices for screening, prevention, and treatment for both short- and long-term health problems, the U.S. Department of State asked the National Academies of Sciences, Engineering, and Medicine to provide advice.  After undergoing a security review, the National Academies’ report is now available.

In examining plausible causes of these illnesses, the committee that conducted the study and wrote the report considered the possibilities of directed, pulsed radio frequency energy, chemical exposures, infectious diseases such as Zika, and psychological issues.  An Assessment of Illness in U.S. Government Employees and Their Families at Overseas Embassies says that among the mechanisms the committee considered, directed, pulsed radio frequency energy appears to be the most plausible mechanism in explaining these cases, especially in individuals with the distinct early symptoms.  Persistent postural-perceptual dizziness (PPPD) — a functional (not psychiatric) vestibular disorder that may be triggered by vestibular, neurologic, or other medical and psychological conditions — is a secondary reinforcing mechanism, as well as the possible additive effects of psychological conditions.
The committee could not rule out other possible mechanisms and found it is likely that a multiplicity of factors explains some cases and the differences between others.  In particular, it could not be certain that the individuals with only the chronic set of signs and symptoms suffered from the same causes and mechanisms as those who reported the initial, sudden onset set of signs and symptoms.  The committee noted that it faced several challenges in its assessment, related to the extreme variability in the clinical cases as well as lack of access to specific health or personal information on the affected individuals.
“The committee found these cases quite concerning, in part because of the plausible role of directed, pulsed radiofrequency energy as a mechanism, but also because of the significant suffering and debility that has occurred in some of these individuals,” said committee chair David Relman, Thomas C. and Joan M. Merigan Professor in Medicine, professor of microbiology and immunology, and senior fellow at the Center for International Security and Cooperation at Stanford University.  “We as a nation need to address these specific cases as well as the possibility of future cases with a concerted, coordinated, and comprehensive approach.”
The report includes a number of recommendations for rehabilitation and actions the State Department should take to enhance responses to future threats to the well-being of its personnel and their families.

The study — undertaken by the Standing Committee to Advise the U.S. Department of State on Unexplained Health Effects on U.S. Government Employees and Their Families at Overseas Embassies — was sponsored by the U.S. Department of State.  The National Academies of Sciences, Engineering, and Medicine are private, nonprofit institutions that provide independent, objective analysis and advice to the nation to solve complex problems and inform public policy decisions related to science, technology, and medicine. They operate under an 1863 congressional charter to the National Academy of Sciences, signed by President Lincoln.

Consensus Study Report: An Assessment of Illness in U.S. Government Employees and Their Families at Overseas Embassies

In late 2016, U.S. Embassy personnel in Havana, Cuba, began to report the development of an unusual set of symptoms and clinical signs. For some of these patients, their case began with the sudden onset of a loud noise, perceived to have directional features, and accompanied by pain in one or both ears or across a broad region of the head, and in some cases, a sensation of head pressure or vibration, dizziness, followed in some cases by tinnitus, visual problems, vertigo, and cognitive difficulties. Other personnel attached to the U.S. Consulate in Guangzhou, China, reported similar symptoms and signs to varying degrees, beginning in the following year. As of June 2020, many of these personnel continue to suffer from these and/or other health problems. Multiple hypotheses and mechanisms have been proposed to explain these clinical cases, but evidence has been lacking, no hypothesis has been proven, and the circumstances remain unclear.

The Department of State asked the National Academies to review the cases, their clinical features and management, epidemiologic investigations, and scientific evidence in support of possible causes, and advise on approaches for the investigation of potential future cases. In An Assessment of Illness in U.S. Government Employees and Their Families at Overseas Embassies, the committee identifies distinctive clinical features, considers possible causes, evaluates plausible mechanisms and rehabilitation efforts, and offers recommendations for future planning and responses.


Diplomats’ Mystery Illness and Pulsed Radiofrequency/ Microwave Radiation
Beatrice Alexandra Golomb. Diplomats’ Mystery Illness and Pulsed Radiofrequency/ Microwave Radiation. Neural Computation. November 2018. 30(11):2882-2985. doi: 10.1162/neco_a_01133.

UC San Diego School of Medicine, La Jolla, CA.

A mystery illness striking U.S. and Canadian diplomats to Cuba (and now China) “has confounded the FBI, the State Department and US intelligence agencies” (Lederman, Weissenstein, & Lee, 2017). Sonic explanations for the so-called health attacks have long dominated media reports, propelled by peculiar sounds heard and auditory symptoms experienced. Sonic mediation was justly rejected by experts. We assessed whether pulsed radiofrequency/microwave radiation (RF/MW) exposure can accommodate reported facts in diplomats, including unusual ones.
(1) Noises: Many diplomats heard chirping, ringing or grinding noises at night during episodes reportedly triggering health problems. Some reported that noises were localized with laser-like precision or said the sounds seemed to follow them (within the territory in which they were perceived). Pulsed RF/MW engenders just these apparent “sounds” via the Frey effect. Perceived “sounds” differ by head dimensions and pulse characteristics and can be perceived as located behind in or above the head. Ability to hear the “sounds” depends on high-frequency hearing and low ambient noise. 
(2) Signs/symptoms: Hearing loss and tinnitus are prominent in affected diplomats and in RF/MW-affected individuals. Each of the protean symptoms that diplomats report also affect persons reporting symptoms from RF/MW: sleep problems, headaches, and cognitive problems dominate in both groups. Sensations of pressure or vibration figure in each. Both encompass vision, balance, and speech problems and nosebleeds. Brain injury and brain swelling are reported in both. 
(3) Mechanisms: Oxidative stress provides a documented mechanism of RF/MW injury compatible with reported signs and symptoms; sequelae of endothelial dysfunction (yielding blood flow compromise), membrane damage, blood-brain barrier disruption, mitochondrial injury, apoptosis, and autoimmune triggering afford downstream mechanisms, of varying persistence, that merit investigation. 
(4) Of note, microwaving of the U.S. embassy in Moscow is historically documented.
Conclusions and relevance:  
Reported facts appear consistent with pulsed RF/MW as the source of injury in affected diplomats. Nondiplomats citing symptoms from RF/MW, often with an inciting pulsed-RF/MW exposure, report compatible health conditions. Under the RF/MW hypothesis, lessons learned for diplomats and for RF/MW-affected civilians may each aid the other.