A mysterious ailment known as "Havana syndrome" has plagued hundreds of U.S. officials while they were working overseas, and so far, there is no known cause. In a new report, U.S. intelligence agencies have determined that it is "unlikely" the condition was caused by a deliberate attack by foreign adversaries — a conclusion that comes as a disappointment to many affected officials and diplomats.

What is Havana syndrome?

In 2016, U.S. and Canadian diplomatic staff in Havana, Cuba, made the first reports about Havana syndrome. According to Politico, the diplomats reported hearing piercing sounds that came from one direction, along with acute nausea and vertigo.

Since then, around 1,500 additional cases among U.S. government officials have been reported worldwide. Although symptoms have varied across individuals, many have said that they experienced a sharp, piercing pain in their head, which then led to dizziness, nausea, migraines, and cognitive issues.

Although many of these cases have been resolved, there are still roughly two dozen current and former U.S. officials who say they are still suffering from chronic ailments that seem to have no clear source.

Although some investigations have posited that the symptoms may be psychological in nature, officials who have experienced Havana syndrome have pushed back on this argument. So far, no clear cause has been identified, but many affected officials say they believe they were victims of a deliberate attack from a foreign adversary.

Last year, an independent panel of experts convened by the intelligence community concluded than a foreign power could have used an external energy source that "pulsed electromagnetic energy" to make people sick.

Similarly, a 2020 investigation by the National Academies of Sciences, Engineering, and Medicine (NASEM) determined that "directed, pulsed radio frequency energy appears to be the most possible mechanism explaining these cases."

What the intelligence community has to say about the condition

In a new report, several U.S. intelligence agencies have determined that it is unlikely that a foreign power was behind cases of Havana syndrome.

In total, seven intelligence agencies, including CIA, reviewed roughly 1,000 cases of "anomalous health incidents" that occurred across 96 countries. Over two years, researchers analyzed data, including forensic information and geolocation data, and looked for any potential patterns linking the cases to one another.

Overall, five agencies concluded that it was "very unlikely" that a foreign adversary caused these conditions, one agency concluded that it was "unlikely," and the remaining agency abstained from making a conclusion about the role of foreign adversaries.

The report also found that no foreign adversary possessed a weapon or collection device that could transmit energy and cause the reported symptoms. Of the agencies, two said they had high confidence in this assessment, three had moderate confidence, and two had low confidence, saying that radio-frequency energy was still a "plausible cause."

According to intelligence officials, the report could not determine one specific cause behind the cases, and they were likely linked to "pre-existing medical conditions, conventional illnesses and environmental factors."

In a statement, CIA Director William Burns said the report was "one of the largest and most intensive investigations in the Agency's history" and that he and his team "stand firmly behind the work conducted and the findings."

However, he also emphasized that the findings "do not call into question the experiences and real health issues that US Government personnel and their family members — including CIA's own officers — have reported while serving our country."

"We will continue to remain alert to any risks to the health and wellbeing of Agency officers, to ensure access to care, and to provide officers the compassion and respect they deserve," Burns added.

Intelligence report receives backlash

According to the Washington Post, representatives and lawyers from individuals affected by Havana syndrome have criticized the new report as "incomplete" and "opaque." They have also called for the intelligence agencies to disclose how they reached their conclusions and to investigate other leads that may have been overlooked.

The group Advocacy for Victims of Havana Syndrome has also pushed back on the report, saying that it "does not track with our lived experiences, nor does it account for what many medical professionals across multiple institutions have found in working with us."

Separately, David Relman, who headed NASEM's investigation into Havana syndrome and co-chaired the intelligence community experts panel, said he still believes that the energy weapon hypothesis remains plausible.

"There are multiple possible explanations for the apparent discrepancy between the failure to identify a malefactor and the plausibility of directed energy as a mechanism," Relman said. "One should not necessarily discount the latter."

According to a senior official, the Biden administration is working to ensure that personnel receive medical care and will process requests for compensation from government employees who have experienced symptoms and had to stop working.

"Nothing is more important than the health and wellbeing of our workforce," Maher Bitar, the senior director for intelligence programs on the National Security Council. "Since the start of the Biden-Harris Administration, we have focused on ensuring that our colleagues have access to the care and support they need. … Our commitment to the health and safety of U.S. Government personnel remains unwavering." (Harris/Hudson, Washington Post, 3/1; Myre, NPR, 3/1; Seligman/Banco, Politico, 3/1)