Learning from the Ongoing Experience of COVID-19

March 31, 2020

March 31 Update: From the Chair

Dear Members of the Pathology and Laboratory Medicine Community,

As we are entering a new phase of the COVID-19 pandemic, there is no doubt that we are living through a historic event. Our colleagues Drs. Joseph St Geme and Louis Bell over at CHOP sent out an important report to all of their physicians last week.

With their permission, I want to share it with you as well, in the hopes that it will provide you with a much-needed sense of perspective. All standard disclaimers apply, of course, and it is always best practice not to extrapolate too much out of limited data.

By distributing this widely, I also want to echo President Amy Gutmann's words in thanking the Penn Medicine team. She describes the gratitude and awe that has filled all of us as we witness your "courage, commitment, and compassion—in addition to an inspiring range of professional expertise—that are being displayed every hour of every day ... You are personally sacrificing to serve patients and to staunch this pandemic. Your brave actions, exercised under exceptional circumstances, fill me with pride and profound respect for your professionalism." 

On a lighter note, I was able to create my first batch of sourdough pancakes, based on a dried starter I revived over the past few days. It feels like being back in the research lab! (And the pancakes were good, but not great. Further iteration required.) I think it is interesting that many of us have started making things since the onset of physical distancing. I know people who have taken up cooking, baking, knitting, learning new musical instruments.

My current hypothesis is that when our social interactions are limited, we feel a need to get in touch in other ways. Perhaps some of us express this as a need to get in touch with our inner wellspring of creativity. This leads me to suggest that, if you are feeling stressed or anxious, perhaps you should think about trying something new, some kind of creative act of making. It might help!

Please continue to take care of yourselves and each other. The better we take care of ourselves, the more we can help our patients.

David Roth
Chair, Pathology & Laboratory Medicine

Report from Joseph St. Geme, MD, Physician-in-Chief and Chair of the Department of Pediatrics at Children's Hospital of Philadelphia (CHOP), and Louis Bell, MD, Chief of the Division of General Pediatrics and Associate Chair for Clinical Activities, CHOP.

Virtually all of us are 'location critical' related to our professional responsibilities at CHOP. The current situation challenges the delicate balance that we maintain in our roles as healthcare professionals and our lives outside the hospital. On the one hand we are called to meet the healthcare needs of children and families, and on the other hand we face the anxiety associated with COVID-19 spreading in our community and potentially to us and our families. In considering this difficult balance, I want to share some information that Lou Bell has assembled, information that is generally reassuring about our risk of acquiring infection from patients and families but that also highlights the need for more knowledge and the importance of rigorous hygiene.

1) The CHOP experience. Our first inpatient at CHOP with COVID-19 infection was a 21-month old with fever, mild intermittent cough, and GI symptoms, who was hospitalized, discharged with CHOP home care, and then re-hospitalized, and who exposed 80 healthcare providers before he was diagnosed with COVID-19.  None of the 80 providers were wearing appropriate personal protective equipment (PPE) at the time of exposure and NONE were infected. This case suggests that limited interaction with an infected patient (even when the interaction is repeated) is associated with a low likelihood of contracting infection.

2) The data on asymptomatic shedding of SARS-CoV-2 are unclear. A modeling study estimated that asymptomatic COVID-19 patients are much less contagious than symptomatic patients, consistent with general infectious disease transmission principles that asymptomatic infected patients typically have a lower burden of virus compared to symptomatic patients (reference #1). The existing evidence from China supports the conclusion that shedding of virus is greatest when individuals are symptomatic.  

3) The incidence of asymptomatic colonization appears to be low, even in high-prevalence areas. For example, studies of foreign nationals evacuated from Wuhan, China, at a time of high COVID-19 prevalence found that the prevalence of asymptomatic colonization with SARS-CoV-2 was 1-2% (references #2,3).  Similarly, in Iceland, 5,000 asymptomatic people were tested, and 48 were positive (less than 1%).   

4)  In a report of a patient with respiratory failure due to undiagnosed COVID-19, 35 clinicians wearing surgical masks were exposed to aerosol-generating procedures (non-invasive ventilation, difficult intubation that required a video laryngoscope plus bougie, extubation), and none of these clinicians acquired COVID-19 (reference #4). This case suggests that standard droplet precautions are generally adequate for protection.

5) Data suggest that fomites may be an important route of spread, underscoring the importance of cleaning the environment and hand-washing. Along these lines, the cruise ship investigation was especially informative. Specifically, SARS-CoV-2 RNA was identified on a variety of surfaces in cabins of both symptomatic and asymptomatic infected passengers up to 17 days after cabins were vacated on the Diamond Princess, but before disinfection procedures had been conducted (Takuya Yamagishi, National Institute of Infectious Diseases, personal communication, 2020). Although these data cannot be used to determine whether transmission occurred from contaminated surfaces, further study of fomite transmission of SARS-CoV-2 aboard cruise ships is warranted. (reference #5)

The story of COVID-19 continues to evolve, and we are learning more each day about the risks of infection and how the SARS-CoV-2 virus is spread.  As an institution, we are dedicated to providing a safe environment for healthcare providers to meet the needs of patients and families. After careful consideration by a very thoughtful working group, we will implement a universal masking policy beginning on Monday, March 30. When you see asymptomatic patients, a surgical mask should provide excellent protection against acquiring COVID-19. Environmental cleaning and consistent hand hygiene will remain critical. For symptomatic patients, the PPE requirements and process of care are clear.

We will all need to continue to care for our patients over the long term, and I believe that we can do it safely if we continue to learn from the ongoing experience with COVID-19, communicate with each other, and be careful. 


1. Li R, Pei S, Chen B, et al. Substantial undocumented infection facilitates the rapid dissemination of novel coronavirus (SARS-CoV2). Science. 2020.

2. Ng OT, Marimuthu K, Chia PY, et al. SARS-CoV-2 Infection among Travelers Returning from Wuhan, China. N Engl J Med. 2020.

3. Hoehl S, Berger A, Kortenbusch M, et al. Evidence of SARS-CoV-2 Infection in Returning Travelers from Wuhan, China. N Engl J Med. 2020.

4. Ng K, Poon BH, Kiat Puar TH, et al. COVID-19 and the Risk to Health Care Workers: A Case Report. Ann Intern Med. 2020.