WASHINGTON — Researchers with the National Institutes of Health published a pair of studies on Monday that found few clinical differences between patients with a mysterious ailment known as “Havana syndrome” and healthy comparison groups.
In one study, NIH researchers took a closer look at the brains of people who were believed to have Havana syndrome and found no consistent evidence of brain injury and no significant differences between that group and a healthy comparison group.
In the second study, scientists ran a battery of tests on 86 US government staff and family members who reported Havana syndrome, comparing them with 30 people who had similar jobs but had no such symptoms, and found that by most clinical and biomarker measures, the two groups were the same.
The mysterious illness first emerged in late 2016, when a cluster of diplomats stationed in the Cuban capital of Havana began reporting symptoms consistent with head …