Respiratory Virus and Measles Information


What Happens if You Continue to Test Positive for COVID-19?

Health Risks You Should Know

You have likely heard about people who have long-term symptoms of COVID-19, or long COVID. Eight in 10 of these patients were never hospitalized with COVID-19, but many have reported neurological and psychological symptoms like "brain fog." 

Another group of people is facing a different long-term battle: They continue to test positive for COVID-19 well past the date of infection. Northwestern Medicine scientists have taken a closer look at patients who met three criteria:

  • Were hospitalized with COVID-19
  • Had neurological symptoms of COVID-19
  • Continue to test positive for COVID-19 more than 14 days after their initial positive test

The study, published in GeroScience, examined how often people met all three criteria, risks they face and the significance of a persistent positive COVID-19 test.

The Northwestern Medicine Neuro COVID-19 research team discovered that, compared to those who did not continue to test positive for COVID-19, patients who continued to test positive more than 14 days after their initial positive test were:

  • More likely to experience delirium, or confused thinking and decreased awareness
  • More likely to have longer hospital stays
  • Less likely to be discharged home
  • More likely to die within six months of getting sick with COVID-19

Positive COVID-19 Test: A Sign of Viral Shedding

Viral shedding is the release of a virus as it multiplies inside your body. If you are shedding virus, it means you can pass it on and infect other people. Testing positive for COVID-19 is an indication of viral shedding.

The study included all patients who required hospitalization for COVID-19 throughout the Northwestern Medicine health system between March and August 2020. Of the 2,518 patients hospitalized during that time, 959 underwent repeat COVID-19 testing at least 14 days from initial testing; 405 of those patients (42%) were found to have persistent viral shedding.

In the persistent shedding group:

  • 54% of patients were men
  • 56% experienced in-hospital delirium, the most common neurologic complication of COVID-19 for people in the hospital
  • Patients were less likely to be discharged to home from the hospital
  • 15% of patients died within six months
  • The most common other medical conditions the patients had were diabetes, chronic kidney disease, hypertension and higher-than-normal body mass index

"This study is one of the first to inform the care of patients who continue to test positive for COVID-19," says Ayush Batra, MD, a Northwestern Medicine neurocritical care specialist who treats patients with COVID-19 and co-authored the study. Dr. Batra notes the team was intrigued to see the strong association between persistent viral shedding and the risk of death. The risk applies regardless of age, how severely their respiratory system was impacted and whether the patients had any delirium. "This suggests that the presence of positive PCR tests has important clinical implications for patients."

"The patients in our study were much more likely to have been delirious while they were hospitalized, even after adjusting for other factors that put patients at risk for delirium," says Eric Liotta, MD, who is also a Northwestern Medicine neurocritical care specialist who treats patients with COVID-19 and a co-author of the study. Dr. Liotta suggests that patients with persistent viral shedding may need more follow-up care to monitor for development of complications following COVID-19.

The strong link between prolonged viral shedding and experiencing delirium also suggests studies are needed to investigate if prolonged viral shedding is related to neurological symptoms in people with long COVID-19. The Northwestern Medicine Neuro COVID-19 Clinic continues to treat many patients who have chronic neurological symptoms of COVID-19, such as brain fog, fatigue, and loss of taste and smell.