The Center of Disease Control (CDC) has modified Covid-19 quarantine recommendations on December 2^nd, 2020. The updated recommendations can be summarized as follows :

• CDC and other scientists have explored changing the current recommendation to quarantine for 14 days after last exposure
• CDC now recommends two additional options for how long quarantine should last. Based on local availability of viral testing, for people without symptoms quarantine can end:
  • On day 10 without testing
  • On day 7 after receiving a negative test result

For the full text of the CDC guidelines, please click on the link highlighted above.

Just about all of us will be happy about that news. HOWEVER, little has been known about how long immunocompromised patients can be contagious. That question is finally being reported on in a letter to the editor of the New England Journal of Medicine titled ‘Shedding of Viable SARS-CoV-2 after Immunosuppressive Therapy for Cancer’ signed by a combined team of researchers at Memorial Sloan Kettering Cancer Center and The Icahn School of Medicine at Mount Sinai (both institutions are located in New York City).

This team analyzed the respiratory samples of 20 immunocompromised patients, diagnosed and hospitalized with Covid-19 in the March-April 2020 timeframe for a prolonged period. ‘These patients included 18 recipients of hematopoietic stem-cell transplants or chimeric antigen receptor (CAR) T-cell therapy and 2 patients with lymphoma.’ Seven of the 20 patients were multiple myeloma patients and ‘15 were receiving active treatment or chemotherapy.’

And now for the conclusions:

• Patients with profound immunosuppression after undergoing hematopoietic stem-cell transplantation or receiving cellular therapies may shed viable SARS-CoV-2 for at least 2 months
• The current guidelines for Covid-19 isolation precautions may need to be revised for immunocompromised patients

And there you have it. Those revised CDC quarantining guidelines do not quite apply to the lot of us, MM (or other hematological malignancies) patients. If we, patients, are exposed and it turns out from testing that we have been infected, then we better not quarantine for short periods of time as we will continue to be infectious for two months, and put those around us at risk.