Patients with COVID-19 are at risk for neurologic complications, including encephalitis, or inflammation of the brain.

“Encephalitis cases have been reported in patients with COVID-19, although on the whole it appears to be a relatively rare complication,” says Michel Toledano, M.D., a Mayo Clinic neurologist.

In the case of encephalitis caused by communicable diseases for which there is a vaccine available, getting vaccinated is the best way of preventing the disease.

“It is important for the public to know that COVID-19 is now a vaccine-preventable disease. The best way to avoid developing potential neurologic complications from COVID-19 is to not get the virus in the first place,” Dr. Toledano says.

Monday, Feb. 22, is World Encephalitis Day. In recognition, the Plummer Building in Rochester, Minnesota; Mayo Clinic Hospital in Arizona; and the sign at the main entrance to Mayo Clinic in Florida will be lighted red beginning at sunset. The Encephalitis Society’s Lights Camera Action campaign will light landmarks worldwide, including Niagara Falls in Ontario and Tower 42 in London.

Encephalitis affects nearly 500,000 people of all ages worldwide each year, according to the Encephalitis Society. The inflammation can be caused by an infection invading the brain, but it also can be caused by the immune system attacking the brain in error, called autoimmune encephalitis. Sometimes the immune attack can be triggered by an infection in the body without the infection itself invading the brain.

Symptoms of encephalitis evolve over days to weeks and include fever, confusion, headache, vomiting, weakness and seizures.

“This is a very serious condition; encephalitis can lead to coma and death,” says Sebastian Lopez, M.D., a Mayo Clinic neurologist. “Early diagnosis and prompt treatment are critical for achieving better neurologic outcomes. Diagnosing the exact cause of encephalitis is important because treatments vary, depending on whether patients have an underlying infection or a reaction caused by the immune system.”

Despite significant progress, encephalitis is still associated with high mortality. Those who recover from the initial illness may struggle with fatigue, paralysis, language impairment, memory difficulties, personality changes and memory problems that may persist for months or permanently.

“The recovery process can be very challenging for those who are struggling with the residual effects of a disease process that family and friends often do not understand,” says Marie Grill, M.D., a Mayo Clinic neurologist. “Increased awareness of encephalitis can help these patients be better supported.”

In 2006, Mayo Clinic created the nation’s first autoimmune neurology clinic specializing in the diagnosis and treatment of encephalitis. Mayo Clinic’s Clinical Neuroimmunology Laboratory tests more than 150,000 patients annually for antibodies targeting the nervous system.

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