Infectious Disease Alert Updates
By Carol A. Kemper, MD, FACP
Clinical Associate Professor of Medicine, Stanford University, Division of Infectious Diseases, Santa Clara Valley Medical Center
Dr. Kemper reports no financial relationships relevant to this field of study.
Masking Our Anxiety
SOURCE: Klompas M, Morris CA, Sinclair J, et al. Universal masking in hospitals in the Covid-19 era. N Engl J Med 2020. doi:10.1056/NEJMp2006372.
Sitting in the intensive care unit (ICU) last week across from one of our renal specialists, who was adjusting her mask and complaining that it sure was uncomfortable to wear all day, I inquired why she was wearing it, then. She seemed puzzled, and responded, “Because of coronavirus.” I had to tell her, she was not really protecting herself, she was protecting me. She said, “So, why am I wearing it, then?”
Experts are divided as to whether all healthcare workers (HCWs) — nay, everyone on the planet — should be wearing a mask. After a local academic center announced their universal mask policy last week, our facility felt arm-twisted into proceeding with similar guidance for our HCWs to mask in clinical areas. But when is it logical to initiate such a measure for HCWs? The pros and cons for this measure are as follows:
- Psychological benefit to the wearer. This is really the whole ball game. Right or wrong, people are psychologically more comfortable wearing a mask right now, allowing them to better focus on their jobs, even if they are physically more uncomfortable. Unfortunately, masks are a component of full personal protective equipment (PPE), including gowns, gloves, and face shields, and by themselves may provide minimal protection to the wearer.
- By wearing a mask, you are helping to protect those around you. Data suggest that a mask reduces the risk of potential transmission from an asymptomatic or minimally symptomatic HCW to fellow workers and patients, although it is unclear to what degree such individuals may contribute to overall transmission.
- Reduced stigmatization for those wearing a mask who come to work with minimal or ambiguous symptoms. At least they feel more comfortable donning a mask if everyone else is.
- Masks are a valuable resource. Until sufficient masks are available for every HCW, every day, they should be conserved for more necessary duties.
- Is it rational (or even ethical) for me to wear a mask every day to work when colleagues in New York are at risk for running out of PPE? I do not feel comfortable with this.
- Masks are uncomfortable. Data suggest mask wearers touch their face and mask more often than those without a mask. And, requiring employees to don a mask only in clinical areas guarantees they will be donning and doffing that mask all day, putting it down on a surface, or stuffing it in their pocket during lunch. Like clothing, I bet by the end of the shift, that mask will be covered with various bacteria, viruses, etc.
- If the goal is to reduce transmission to other employees, why is it recommended to remove the mask in nonclinical areas?
- On the other hand, if the goal is to reduce transmission to patients, then why are many hospital workers with limited or no contact with patients wearing a mask?
- Will it be practice or policy for HCWs to wear a mask in the healthcare environment? Is this one more thing a hospital is supposed to enforce? Just as there are some HCWs who desperately want to wear a mask, there are some who do not. Can you force them to wear a mask?
I do not see where personal comfort enters into this discussion. Good healthcare must be rational and based on sound principles, not fear. There must be some balance between the prevalence of disease in the population, the risk of transmission from asymptomatic individuals, and disease severity that leads to this decision. It feels like this decision is just masking our anxiety.
Is it Luck or Genetics?
SOURCE: Deng X, Gu W, Federman S, et al. A genomic survey of SARS-CoV-2 reveals multiple introductions into Northern California without a predominant lineage. https://doi.org/10.1101/2020.03.27.20044925.
On Feb. 26, 2020, our facility, located in Santa Clara County, CA, diagnosed the second case in the United States of community-acquired SARS-CoV-2 infection in a 68-year-old woman, admitted to the intensive care unit (ICU) five days earlier with progressive respiratory failure. This case prompted the Centers for Disease Control and Prevention (CDC) to expand testing to hospitalized patients with acute respiratory failure of uncertain cause (e.g., no known exposure by travel or close contact with another patient with confirmed SARS-CoV-2). The patient had been cared for in our ICU for five days, requiring bilevel positive airway pressure (BiPAP) with no precautions. A total of 82 staff were exposed to this patient, many of whom had high-risk exposure, including 32 nurses, 14 respiratory therapists, and eight physicians (including two intensivists, one pulmonologist, and several hospitalists). Only one of these individuals (1.2%), a nurse in the step-down ICU unit who cared for the patient on her first night of admission, subsequently developed symptoms on day 9 post-exposure, and tested positive for SARS-CoV-2. No one in her family developed symptoms or became positive. Two other staff who were exposed to the patient developed some symptoms (upper respiratory infection symptoms in one, and sore throat in the other) and both tested negative.
Since then, none of our healthcare staff have been diagnosed with SARS-CoV-2 infection related to a known workplace exposure, although sporadic exposures here and at other facilities have occurred (we are surprised at how many healthcare workers [HCWs] work in multiple facilities.) Stanford Occupational Health recently performed SARS-CoV-2 nasopharyngeal testing on 1,200 of their staff with their home-based assay, and 2.8% were positive, with most exposed at home within family clusters.
How have we been so lucky in our area with such minimal HCW exposure? Our local experience seems different from that described in Washington state or New York — or Italy — where reports of HCW infection seem more frequent. Washington experienced the first large community outbreak of infection, extending from their first identified case on Jan. 19 in a patient from Wuhan, China. This outbreak had serious consequences for HCWs at a local nursing facility. Since then, the vast majority of cases in Washington state have shared a strain of SARS-CoV-2 now recognized as the WA1 lineage, consistent with persistent community transmission of this dominant viral strain.
Perhaps the answer is there is more than one strain of SARS-CoV-2 in circulation in different areas, and some are more transmissible than others. Deng and colleagues analyzed nasal swab specimens from 29 patients diagnosed with SARS-CoV-2 infection throughout Northern California between Feb. 3 and March 15, 2020. The 29 individuals came from nine different counties, including San Francisco, San Mateo, Santa Clara, Sonoma, and Solana counties. Nine samples came from passengers and crew aboard two Princess cruises in February and March. Fourteen of the samples came from people without a source of transmission by travel history or an identified confirmed contact. Three samples came from Solano County, including the first case of community transmission with respiratory failure of uncertain cause and two HCWs; a husband and wife in San Mateo with infection; another case from San Mateo in a recent traveler from Switzerland; a cluster of five cases in Santa Clara County thought to be related to workplace exposure over a two-week period; one case in Sonoma; and several others. Metagenomics sequencing with spiked primer enrichment was used to enrich and assemble viral genomes directly from the clinical specimens, and these were compared phylogenetically with 342 SARS-CoV-2 genomes logged into the GISAID as of March 17.
Interestingly, the nine sequenced genomes from crew members and passengers aboard the two Princess cruise ships clustered within the WA1 lineage. Virus from the infected passengers on the second cruise shared two mutations with virus obtained from a passenger on the first cruise, suggesting that virus was passed from passengers to crew, and then on to passengers on the second cruise. Their WA1 virus appeared to originate in Washington state.
The three Solano cases had their own distinct cluster, separate from the WA1 lineage, confirming transmission of infection from the patient to the two HCWs. The husband and wife in San Mateo County shared their own virus, which was distinct from other recognized clusters. Several other cases and their contacts were more closely related to non-WA1 ancestral SARS-CoV-2 lineages observed in China. In contrast, the strain from the single San Mateo County traveler from Switzerland fell into sequences commonly seen in Europe. Interestingly, three further viral genomes from Northern California patients also fell within a viral lineage observed in Europe, including an individual recently returned from a trip to New York.
The Santa Clara County cluster was surprising. Three of the employees in the building each had a distinct strain of virus; one of these shared their virus with two household contacts, and these three made their own cluster distinct from any of the other strains observed in the database. This indicates that three genetically distinct SARS-CoV-2 viruses were introduced into the same building within a two- to three-week period. Virus from a patient in Solano County fell within this distinct cluster of three cases, although no recognizable link could be established between these individuals.
In contrast to the dominant WA1 virus circulating in Washington state, this phylogenetic data beautifully demonstrates that at least eight different lineages of SARS-CoV-2 were identified in individuals diagnosed during a six-week period in February and March in Northern California. This strongly suggests the separate introduction of multiple different strains throughout the Bay Area and Northern California counties. In contrast, the dominant strain in Washington is the WA1 strain with sustained community transmission, and obviously has involved HCWs. This must be a more transmissible strain. The WA1 strain has become distinctly recognizable by its three key single nucleotide variants, and is now being observed in other states, such as Utah, Illinois, and Minnesota. It would be of interest to re-examine a larger number of samples from individuals in Northern California to see if some of these observed strains were epidemiological dead-ends.
Neurologic Infection from SARS-CoV-2
SOURCE: Poyiadji N, Shahin G, Nourjaim D, et al. COVID-19-associated acute hemorrhagic necrotizing encephalopathy: CT and MRI features. Radiology 2020. doi: 10.1148/radiol.2020201187.
Cases of suspected neurologic involvement from SARS-CoV-2 have been few. Many clinicians involved in the treatment of the earliest cases of SARS-CoV-2 have described unremarkable spinal taps and negative central nervous system imaging, even in patients with altered mental status.
One case stands out: A 55-year-old airline attendant was admitted to the hospital in Detroit with three days of fever, cough, and altered mental status. An initial CXR was unremarkable, and all relevant bacterial and viral studies were negative. During the initial course of hospitalization, a nasopharyngeal swab for SARS-CoV-2 was positive. A traumatic lumbar puncture was difficult to interpret, but viral studies for varicella zoster virus, herpes simplex virus, and West Nile virus were negative. Magnetic resonance imaging showed dramatic changes with T2 Flair hyperintensity within the medial temporal lobes and thalami with evidence of focal areas of hemorrhage and rim enhancement. It is believed this is the first case of acute necrotizing hemorrhagic encephalopathy from SARS-CoV-2 infection. I understand she eventually developed evidence of progressive respiratory involvement and radiographic abnormalities.
Masking Our Anxiety; Is it Luck or Genetics? Neurologic Infection from SARS-CoV-2
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