'Pandemic within the pandemic': Long COVID affects a third of COVID-19 survivors, study says

In May, the World Health Organization declared the COVID-19 public health emergency over. But thousands of patients diagnosed with long COVID still suffer lingering neurological, pulmonary and cardiac effects, according to a study by the Northwestern Medicine Comprehensive COVID-19 Center published in the American Journal of Medicine.

The third-leading neurological disorder in the United States, long COVID is characterized by shortness of breath, palpitations, brain fog, fatigue and other symptoms.

Described as "the pandemic within the pandemic," long COVID affects about one-third of COVID-19 survivors and continues despite vaccinations and boosters.

From May 2020 to February 2022, researchers at the Comprehensive COVID-19 Center, or CCC, evaluated 1,802 patients (350 post-hospitalization and 1,452 non-hospitalized). Patients typically sought treatment from neurology (49%), pulmonology (25%) and cardiology (12%) specialists. Long haulers also received treatment from otolaryngology, gastroenterology, infectious diseases, endocrinology, nephrology, hematology, dermatology, psychiatry and rheumatology specialists.

One of the first centers in the U.S. to treat long COVID patients, CCC clinicians continue to see about 100 patients monthly.

"We know COVID is a respiratory disease, but long COVID affects predominantly the nervous system," Dr. Igor Koralnik, chief of neuroinfectious diseases and global neurology at Northwestern Medicine, said during a news conference Thursday.

Koralnik and his colleagues hypothesize that long COVID is a new autoimmune syndrome possibly caused by the persistence of the virus that "confuses the immune system into thinking something is abnormal in the body and needs to be attacked," he said.

Eighty-five percent of patients reported decreased quality of life, 51% had cognitive impairment, 45% had altered lung function, 83% had abnormal CT chest scans, and 12% had an elevated heart rate.

While widespread vaccinations have reduced the rate of acute COVID infection, little is known about the outcomes of patients seeking care at post-COVID centers, and treatments vary among institutions, said Dr. Marc Sala, who codirects the CCC with Koralnik.

"This study will help us understand what the biological causes of those symptoms are and how to structure clinics to care for them," said Sala, a pulmonary and critical care specialist at Northwestern Medicine. He encourages clinics to take a multidisciplinary approach to treating long COVID patients.

"There is not a one-size-fits-all long COVID," said Sala, adding that the effects of long COVID differ depending on the severity of a patient's COVID-19 illness.

"Some patients who had severe COVID-19 may have sustained permanent organ damage, while persistent symptoms in those with mild initial disease may be caused by different mechanisms," requiring a precise, individualized approach to long COVID care, Koralnik said.

For more information on long COVID, see To schedule a CCC appointment, call (312) 926-9900.

Dr. Marc Sala examines a long COVID patient at the Northwestern Medicine Comprehensive COVID-19 Center. Courtesy of Northwestern Medicine
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