What Causes The Bizarre Illness Known As 'Havana Syndrome'? The FBI Wants To Know

Beginning in December 2016, a CIA agent stationed at the US Embassy in Havana began showing signs of a mysterious illness that affected his hearing and vision. As more agents at the embassy began falling ill, the term “Havana Syndrome” was born. Since then, US diplomats, spies, and officials across the globe have experienced the syndrome, which often starts as an intense ringing in the ears.

Government agencies have speculated that Havana Syndrome was nothing more than mass hysteria, while medical personnel wondered if those who fell ill were suffering from concussions. Despite a great deal of research into the phenomenon, what - or who - causes Havana Syndrome is not publicly known.


  • More Than 200 US Officials Have Reported Experiencing A Mysterious Brain Illness

    Although Havana Syndrome began as a handful of cases in Cuba, more than 200 US officials have reported contracting the syndrome. The illness is also not unique to the US Embassy in Havana, Cuba. US officials, diplomats, and spies located in Russia, China, Colombia, and Uzbekistan have all experienced symptoms of Havana Syndrome. While there is no clear definition of the still-mysterious illness, the US government commonly refers to it as an “anomalous health incident” that affects the brain, which in turn can affect the entire nervous system.

    Havana Syndrome has even been reported in Washington, DC. In November 2020, a National Security Council senior official reported intense physical symptoms as he left the White House. The official had been out of the country and just returned home when the symptoms began. The official told The New Yorker about his symptoms:

    In a matter of about seven minutes, I went from feeling completely fine to thinking, “Oh, something’s not right,” to being very, very worried and actually thinking I was going to die.

  • Symptoms Include Dizziness, Nausea, Headaches, Vertigo, And Vision Problems

    In the earliest cases of Havana Syndrome, the chief complaint was a persistent ringing in the ears, which caused severe headaches. As the syndrome has spread, symptoms have expanded to include vertigo, nosebleeds, brain fog, tinnitus, loss of vision and hearing, and loss of muscle control. Some officials have reported losing the ability to read or drive a car as a result of Havana Syndrome. Although some government personnel have seemingly recovered from their illness, others have reportedly gone into early retirement due to the adverse effects on their health.

    Those who have had Havana Syndrome often describe it as feeling like they've been hit with a “blast of energy.” In 2019, two US officials reported that they experienced painful ringing in their ears while in a London hotel room, but the ringing lessened when they moved to a different room. These two officials have since experienced long-term symptoms of Havana Syndrome, including swollen lymph nodes and balance issues.

  • Some Of Those Afflicted Have Reported Physical Damage Consistent With Concussion
    Photo: Max Andrews / Wikimedia Commons / CC BY-SA 3.0

    Some Of Those Afflicted Have Reported Physical Damage Consistent With Concussion

    Medical staff at the US Embassy in Havana initially believed that the CIA agents experiencing what would eventually become known as Havana Syndrome had actually suffered concussions. As a result, the staff took blood samples so they could perform tests looking for biomarkers in the blood that would show if brain tissue had been damaged.

    The samples were stored in a refrigerator until they could be tested, but when Hurricane Irma caused mass power outages throughout Cuba, the samples were destroyed. Because these biomarkers are present for a limited time, there was no point in getting second blood samples from the CIA agents.

    MRIs conducted at the University of Pennsylvania showed no signs of concussion but did show signs of the brain structure being altered. One doctor referred to the strange findings as “a concussion without a concussion.”

  • It All Started With A CIA Officer At A Cuban Embassy Who Fell Ill In December 2016
    Photo: Bjen78 / Wikimedia Commons / CC BY 4.0

    It All Started With A CIA Officer At A Cuban Embassy Who Fell Ill In December 2016

    In 2015, the US opened an embassy in Cuba after the two countries had worked to mend their relationship. Within a year, a member of the CIA stationed at the embassy began experiencing bizarre symptoms that they couldn't explain. The agent's illness was kept secret, but as more embassy staff in Cuba became ill, the term “Havana Syndrome” was coined.

    Although the US reportedly suspected a sect of the Cuban government to be at the root of the problem, the theory lost credibility as US officials in faraway countries began falling ill. The Cuban government also noted at the time that it was conducting its own investigation into the potential attacks on US officials. Rex Tillerson, then US Secretary of State, removed all diplomats from the embassy in 2018.