Patients with COVID-19 who are profoundly immunocompromised after undergoing hematopoietic stem-cell transplant or chimeric antigen receptor (CAR) T-cell (CAR-T) therapy may shed viable severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) for as long as 2 months, according to an editorial published in The New England Journal of Medicine.

According to the editorial, although more is known about how long immunocompetent patients shed SARS-CoV-2, there is a lack of data on how long immunocompromised patients are contagious. To find out more, they used cell cultures to detect viable virus in serially collected respiratory samples taken from 20 immunocompromised patients diagnosed with COVID-19.

Of the 20 patients, 15 were receiving active treatment or chemotherapy; 18 had received hematopoietic stem-cell transplant or CAR-T therapy; 11 had severe COVID-19.

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Seventy-eight samples were collected from the 20 patients. Viral RNA was detected up to 78 days after the onset of symptoms. Viable virus was detected in 71% of nasopharyngeal samples from the first day of laboratory testing.

The 3 patients with viable virus for more than 20 days had undergone allogenic transplant or CAR-T therapy within the previous 6 months. These patients remained seronegative for antibodies to viral nucleoprotein.

Based on these results, “the current guidelines for COVID-19 isolation precautions may need to be revised for immunocompromised patients,” the writers concluded.


Aydillo T, Gonzalez-Reiche AS, Aslam S, et al. Shedding of viable SARS-CoV-2 after immunosuppressive therapy for cancer. N Engl J Med. Published online December 1, 2020. doi:10.1056/NEJMc2031670.