COVID-19 patients who receive cancer treatments that suppress the immune system can remain contagious and spread the coronavirus for two months or longer, according to a study published on Tuesday.
The U.S. Centers for Disease Control and Prevention (CDC) currently recommend that when patients have compromised their immune systems, healthcare professionals take extra precautions, such as wearing a respirator instead of a face mask, and isolate patients for up to 20 days after symptoms occur.
In the new study, researchers analyzed sputum and swab samples from 20 immunocompromised cancer patients infected with the new coronavirus. They found that three, including one that remained contagious for 61 days, were contagious for more than three weeks after their symptoms began.
Three patients had been treated with either a stem cell transplant or genetically engineered immune cells called CAR T cells in the previous six months. Two out of three people had developed severe COVID-19. None of them had antibodies to the virus.
In a letter published in the New England Journal of Medicine, the researchers said that current public health recommendations for COVID-19 patients with weakened immune systems are based on limited data and may need revision.
“We know from several studies that if you’re … healthy, you are no longer infectious after the first week of illness. But there is very little we know about immunocompromised patients,” said Mini Kamboj, one of the study’s authors from the Memorial Sloan Kettering Cancer Center. “Is that 20 days enough or do we need to exercise precautions for longer than that?”
While only a small fraction of cancer patients with COVID-19 are likely to remain contagious for a long time, “this is a residual risk we have to address,” said Kamboj. “We need to be open-minded about how (how much) longer immunocompromised patients may pose an infection risk for others.” -reuters-