Cassie and Len Calabrese’s COVID-19 Corner: Issue #6

Sorting out asymptomatic/pauci-symptomatic transmission and the importance of masks in the office and in life

This week we would like to bring your attention to a couple of articles published on the asymptomatic SARS-CoV-2 infection. We think this is a really important concept and reinforces the high importance of continuing to wear masks and social distancing while in public. As society opens back up, some states are faring better than others. As you have all likely seen on the news, states such as Arizona, Texas, and Florida are not doing so hot in terms of their daily COVID-19 case counts. Friends of ours were looking for a respite from their home in Washington D.C. and drove to Florida to spend time around their in-law’s pool. They observed a noticeable lack of social distancing and masking, felt uncomfortable, and drove right back home. This is only a personal anecdote, but we believe there is a direct correlation with the lack of infection prevention practices in public and the rising number of cases in these areas.

Many states, including us in Ohio, were spared from a surge and none of our hospitals were overrun with COVID-19 cases. Social distancing and masking had a big role to play in that success, and now it is more important than ever to not let up these practices. We are learning that a high proportion of patients may have asymptomatic infections.

We encourage you to check out a review by Daniel Oran and Eric Topol was published in the Annals of Internal medicine last week that synthesized the available evidence on asymptomatic SARS-CoV-2 infection ( The authors inform us that asymptomatic cases may account for up to 40-45% of COVID-19 infections, and it is possible for these asymptomatic cases to transmit SARS-CoV-2 for an extended period of time. It is important to appreciate the difference between asymptomatic patients (who never develop symptoms) and pre- or pauci-symptomatic patients who will go on to develop symptoms of COVID-19, but were asymptomatic at the time of testing, in the studies they review in the article. Regardless of which category infected individuals reside, the take away here for all of us, is that when we are out in public (at the grocery store or in our offices) it is quite possible to come into contact with individuals who deem themselves completely healthy but are active spreaders of the virus. Thus this is why maintaining social distancing, and masking in public (especially when social distancing is not feasible) is of the utmost importance.

Another great piece published this week was a letter to the editor in the New England Journal of Medicine where the authors report on the natural history of asymptomatic SARS-CoV-2 infection on the Diamond Princess Cruise ship ( If you recall, the Diamond Princess returned to Japan for quarantine on February 2, 2020, after having transferred a passenger one week earlier who was ultimately diagnosed to have COVID-19. By March 16th, 712 (19.2%) of 3711 passengers and crew tested positive. At the time of testing, 331 (46.5%) were asymptomatic although later found that some had subclinical changes on lung imaging (see Annals article referenced above). In the NEJM letter, Sakurai, et al. further describe 96 of the persons who initially were asymptomatic at the time of the positive test. Eleven of these patients went on to develop symptoms of COVID-19 in a median of 4 days after first positive PCR, indicating they were “presymptomatic” at the time of testing. The risk of being presymptomatic rather than remaining asymptomatic increased with age. Among the totally asymptomatic cases, the median days of shedding were around nine! 

Moving forward we must champion the rationale and the use of masks and social distancing in our infusion clinics and in our offices. That means in the break rooms and beyond. Leading by example by wearing our own face masks, making efforts at social distancing, and practicing hand hygiene are all lessons for those around us. We believe rheumatologists should not only adhere to such guidelines but champion the adoption of these practices by their patients and their patients’ families. Finally the way we look at wearing masks, and the rationale we explain to our patients is that when we wear our masks it’s not about us. It’s not about being frightened or weak it’s about kindness and telling those around us “I care about you and your loved ones.”

Please give us a shout out with any questions!


Leonard H. Calabrese, DO, is the head of the RJ Fasenmyer Center for Clinical Immunology and Vice-Chair of the Department of Rheumatic and Immunologic Diseases at Cleveland Clinic  Dr. Calabrese has lectured nationally and internationally on the subjects of immunology, rheumatology, and viral diseases. He is the author of more than 400 published peer-reviewed articles, book chapters, and reviews. @LCalabreseDO

Cassandra Calabrese, DO, is a staff physician in the Department of Rheumatic and Immunologic Diseases and the Department of Infectious Diseases at Cleveland Clinic and directs the combined Rheumatology-Infectious Disease training program. She also directs the Clinic for immune-related adverse events form cancer immunotherapy within the department of Rheumatic and Immunologic Diseases. @CCalabreseDO

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