New research suggests millions of people who tested negative for COVID-19 may have long COVID

COVID-19 test

Chicago, IL – August 23, 2023 – Early in the COVID-19 pandemic, testing was limited, and many individuals couldn’t get a positive diagnosis during the window of viral shedding. This was especially important for COVID long-haulers, who were struggling with lingering symptoms such as brain fog, fatigue and cognitive impairment. Without a positive COVID-19 test, many were denied appointments at post-COVID clinics in the United States, but the Northwestern Medicine Neuro COVID-19 Clinic was an exception, evaluating new patients without a confirmed COVID-19 diagnosis.  

According to new research published in Neurology® Neuroimmunology & Neuroinflammation, an official journal of the American Academy of Neurology, Northwestern Medicine researchers show 41% of long-haulers who initially tested negative for COVID-19 had antibody or T cell responses indicating they were exposed to the virus. This new research performed with very sensitive immunologic assays suggests post-COVID clinics shouldn’t require a positive COVID-19 test in order to provide care to long-haulers.

“It’s estimated that nearly 10 million Americans experienced neurologic manifestations of long COVID without an official COVID-19 diagnosis due to limited access to COVID testing in the first year of the pandemic or testing outside the window of detection,” said Igor Koralnik, MD, chief of neuroinfectious diseases and global neurology at Northwestern Medicine, who oversees the Neuro COVID-19 Clinic and is co-director of the Northwestern Medicine Comprehensive COVID-19 Center. “Millions of people in the United States have been rejected by the medical establishment and stigmatized because they didn’t carry a definite diagnosis of COVID-19 when they presented with their long COVID symptoms. We hope those people feel vindicated by our study.”