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CHICAGO — According to a study, people who have battled a COVID-19 infection can still experience neurological symptoms 15 months later.

Northwestern Medicine said this is the largest, longest-running COVID study in the world. Its conclusion is that while some make full recoveries from the virus, others are feeling lingering effects — even two years later.

These patients, whose average age is 43, had COVID-19 in the early part of the pandemic, between March and November of 2020.

All their symptoms were mild, with cough and sore throat. None were hospitalized.

Emily Caffee is a Chicago area physical therapist and was training as a competitive rower when COVID symptoms hit her in March 2020. She’s one of the 52 patients taking part in the follow-up study by researchers at Northwestern Medicine’s neuro-COVID-19 clinic.

“I did eventually return to work after a week of being out sick,” Caffee said. “But if 100% was the level beforehand, I returned as a barely functional adult.”

The clinic has seen more than 1,400 patients so far. Many have never been hospitalized for COVID, nor have they had severe symptoms.

Still, the latest study shows 81% continue to experience fatigue and more than 70% complain of brain fog, 65% of numbness and tingling and 54% of headaches and dizziness.

While most of those symptoms have decreased since the initial study, others have increased in severity. Namely, blood pressure variation and gastrointestinal issues in about half of the long-haul patients.

Sareen Ali, a Northwestern Medical student researcher, said COVID-19 comes in all shapes and sizes.

To see the published study, visit this website.