The hidden long-term cognitive effects of COVID-19 – Harvard Health Blog

The COVID pandemic has now claimed as many American lives as World War I, the Vietnam War, and the Korean War combined. Most of these deaths are due to the well-known pulmonary complications of the coronavirus. It has become increasingly recognized, however, that the virus also attacks the nervous system. Doctors in a large Chicago medical center found that more than 40% of patients with COVID showed neurologic manifestations at the outset, and more than 30% of those had impaired cognition. Sometimes the neurological manifestations can be devastating and can even lead to death.

However, new research is now suggesting that there may be long-term neurologic consequences in those who survive COVID infections, including more than seven million Americans and another 27 million people worldwide. Particularly troubling is increasing evidence that there may be mild — but very real — brain damage that occurs in many survivors, causing pervasive yet subtle cognitive, behavioral, and psychological problems.

How COVID damages the brain

COVID can cause damage to the brain directly by encephalitis, which may have devastating or subtle consequences. In one British study of 12 patients with encephalitis, one made a full recovery, 10 made a partial recovery, and one died. This study also found that a number of patients with COVID suffered strokes. In fact, COVID infection is a risk factor for strokes. A group of Canadian doctors found that individuals over 70 years of age were at particularly high risk for stroke related to COVID infection, but even young individuals are seven times more likely to have a stroke from this coronavirus versus a typical flu virus.

Autopsy data from COVID patients in Finland suggests that another major cause of brain damage is lack of oxygen. Particularly worrisome is that several of the patients

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