Comorbidities May Result in Longer Duration of Positive COVID-19 PCR Tests


A recent study conducted by investigators from the Boston Medical Center has discovered that individuals with certain comorbid conditions who had an infection with COVID-19 may continue to receive positive polymerase chain reaction (PCR) test results for the SARS-CoV-2 virus for a longer period of time compared to those without them.

Results from the study were published in the journal Open Forum Infectious Diseases.

This study of SARS-CoV-2 PCR retesting in both immunocompromised and non-immunocompromised patients is the largest of its kind to date.

"There are limited data on how long immunocompromised individuals continue to test positive for COVID-19 after initial infection," Rachel Epstein, a corresponding author on the study said. "This study challenges whether the current recommendations to consider retesting severely immunocompromised individuals and use negative SARS-CoV-2 PCR test results to end isolation is necessary."

For the study, the team of investigators analyzed data from 3,758 individuals who were retested using the SARS-CoV-2 PCR test following an initial positive result. The investigators separated the participants into groups by age and immunocompromised severity. The 3 groups were sever, moderate and not immunocompromised.

Results from the study showed that median length of time for severely immunocompromised patients to receive a negative SARS-CoV-2 PCR test result was 22 days. For the moderate and non-immunocompromised groups, the median time was 20 and 16 days, respectively.

Additionally, those with 3 or more comorbid conditions took longer for a negative SARS-CoV-2 PCR test result.

"Retesting individuals to end isolation precautions can delay care, and may not be necessary even for most severely immunocompromised people,” Epstein said. “Particularly as most transmission studies demonstrate that it is highly unlikely for someone to transmit infection more than 20 days into their illness.”