A 71-year-old cancer patient who tested positive for the novel coronavirus but never showed symptoms remained infectious for 70 days, according to a case study. It started when she went to the emergency room for low back and lower extremity pain and underwent surgery, which then landed her at a rehabilitation facility, according to the study, which was published in the journal Cell.
The woman, who was not identified in the report, has a 10-year history of chronic lymphocytic leukemia, acquired hypogammaglobulinemia, anemia and chronic leukocytosis. After arriving at the emergency room in February she underwent surgery for a spinal fracture and stenosis that was related to her cancer. She was transferred to a rehab center, but went back to the hospital for anemia. Once cleared, it was determined that she could not return to the rehab center due to an outbreak of COVID-19.
“A chest CT performed on February 28, 2020, was unremarkable,” the case report said. “The patient had no respiratory or systemic symptoms during this time. Because she was residing in the rehabilitation facility around the time of the COVID-19 outbreak, she was tested and found positive for SARS-CoV-2 on March 2, 2020.”
She was then isolated and staff wore personal protective equipment while caring for her. For the next 15 weeks she was tested 14 times for COVID-19, with each test returning a positive result. In fact, samples detected infectious virus on Day 49, and again on Day 70, which actually marked the highest viral load.
It wasn’t until mid-June, some 105 days after her initial positive test, that she tested negative on four consecutive swabs. Interestingly, she had received convalescent plasma on Day 71 and again on Day 82, but the virus persisted. They did note that initial viral loads decreased, but subsequently increased again.
“The patient remained asymptomatic throughout the course of infection despite the isolation of infectious SARS-CoV-2 49 and 70 days past the initial diagnosis, much longer than shedding of infectious virus up to Day 20 as reported previously,” the study authors noted. “The information available to date on SARS-CoV-2 infection in immunocompromised patients, including those with cancers such as CLL, is limited, and mostly focuses on disease severity and outcome.”
The study authors say their data suggest long-term shedding of infectious virus may be a concern in certain immunocompromised patients, which could change testing and disease mitigation strategies among this population.
“Many current infection control guidelines assume that persistently PCR positive patients are shedding residual RNA and not infectious virus, with immunocompromised patients thought to remain infectious for no longer than 20 days after symptom onset,” the authors wrote. “Here, we show that certain patients may shed infectious, replication-competent virus for much longer durations than previously recognized.”
One potential reason, they note, is that immunocompromised patients may have a wide variety of conditions or undergo treatments that alter the immune system, creating opportunities for prolonged viral replication.