In March 2020 -still the early days of the U.K.'s COVID-19 crisis-Rhys Thomas, a neurologist at Newcastle University, got a call at home from a concerned colleague. The colleague's cousin was hospitalized, critically ill with COVID-19, and had developed brainstem encephalitis, a severe inflammatory condition of the brain causing a suite of symptoms, from eye problems to balance problems and drowsiness. He wanted to know if Thomas knew anything about these conditions. At the time, the research coming out of Wuhan, China, only suggested a mild whiff of neurological symptoms-headache, dizziness, and the loss of taste and smell. Clearly the virus could affect the brain in some ways, but it wasn't, Thomas thought then, anything serious. But this report sounded much more concerning. Symptoms like this patient's would mean the virus was accessing more of the nervous system than scientists originally thought.