A team of researchers and doctors has now reported the case of one woman with leukemia who had no symptoms of COVID-19 but 70 days after her first positive test, she was still shedding infectious SARS-CoV-2 particles.
This result is much longer than previous reports of hospitalised adults found shedding infectious SARS-CoV-2 virus up to 20 days after their COVID-19 diagnosis, plus other accounts of people shedding genetic material from the virus up to 63 days after their symptoms first appeared.
The new report should alert doctors and public health experts alike to the fact that people without symptoms and with weakened immune systems, such as cancer patients, can seemingly shed the SARS-CoV-2 virus for a really long time. In this case, even months.
"Although it is difficult to extrapolate from a single patient, our data suggest that long-term shedding of infectious virus may be a concern in certain immunocompromised patients," the research team wrote in their paper describing the case.
An estimated 3 million people in the US have some kind of condition that compromises or weakens their immune system, making them vulnerable to infections. Cancer patients on chemotherapy and transplant recipients who take immunosuppressant drugs are some examples.
"As this virus continues to spread, more people with a range of immunosuppressing disorders will become infected, and it's important to understand how SARS-CoV-2 behaves in these populations," said virologist and co-author Vincent Munster from the US National Institute of Allergy and Infectious Diseases.