By Christian Hoffmann &
Bernd S. Kamps
Virology
Yan R, Zhang Y, Li Y, Xia L, Guo Y, Zhou Q. Structural basis for the recognition of SARS-CoV-2 by full-length human ACE2. Science. 2020 Mar 27;367(6485):1444-1448. PubMed: https://pubmed.gov/32132184. Full-text: https://doi.org/10.1126/science.abb2762
Using cryo–electron microscopy, it is shown how SARS-CoV-2 binds to human cells. The first step in viral entry is the binding of the viral trimeric spike protein to the human receptor angiotensin-converting enzyme 2 (ACE2). Authors present the structure of human ACE2 in complex with a membrane protein that it chaperones, B0AT1. The structures provide a basis for the development of therapeutics targeting this crucial interaction.
Lan J, Ge J, Yu J, et al. Structure of the SARS-CoV-2 spike receptor-binding domain bound to the ACE2 receptor. Nature. Published: 30 March 2020. Full-text: https://www.nature.com/articles/s41586-020-2180-5
To elucidate the SARS-CoV-2 RBD and ACE2 interaction at a higher resolution/atomic level, authors used X-ray crystallography. Binding mode was very similar to SARS-CoV, argueing for convergent evolution of both viruses. The epitopes of two SARS-CoV antibodies targeting the RBD were also analysed with the SARS-CoV-2 RBD, providing insights into the future identification of cross-reactive antibodies.
Shang J, Ye G, Shi K. Structural basis of receptor recognition by SARS-CoV-2. Nature 2020, March 30. https://doi.org/10.1038/s41586-020-2179-y
How well does SARS-CoV-2 recognize hACE2? Better than other coronaviruses. Compared to SARS-CoV and RaTG13 (isolated from bats), ACE2-binding affinity is higher. Functionally important epitopes in SARS-CoV-2 RBM are described that can potentially be targeted by neutralizing antibody drugs.
Epidemiology
Luo C, Yao L, Zhang L, et al. Possible Transmission of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in a Public Bath Center in Huai´an, Jiangsu Province, China. JAMA Netw Open. 2020 Mar 2;3(3):e204583. PubMed: https://pubmed.gov/32227177. Full-text: https://doi.org/10.1001/jamanetworkopen.2020.4583
A cluster-spreading event in Huai’an (China), in which a patient may have transmitted the virus to 8 other individuals via bathing in a public bath center (sauna, bath, 25 to 41 °C and humidity of approximately 60%). Transmissibility appears not to be reduced in warm and humid conditions.
Cereda D, Tirani M, Rovida F, et al. The early phase of the COVID-19 outbreak in Lombardy, Italy. Preprint. Full-text: https://arxiv.org/abs/2003.09320
Still looking for patient zero in Italy (not found). However, this important study of 6,000 laboratory-confirmed cases tracks how the outbreak unfolded in the region. By the time the first case was detected, the virus had already spread (since January) to most towns and cities in southern Lombardy.
Comorbidities
Bousquet J, Akdis C, Jutel M, et al. Intranasal corticosteroids in allergic rhinitis in COVID-19 infected patients: An ARIA-EAACI statement. Allergy. 2020 Mar 31. PubMed: https://pubmed.gov/32233040. Full-text: https://doi.org/10.1111/all.14302
A joint statement of the European Academy of Allergology and Clinical Immunology, following the results of the questionnaire. Bottom line: Stopping intranasal steroids is not advised, until we know better.
Clinical
Back A, Tulsky JA, Arnold RM. Communication Skills in the Age of COVID-19. Ann Intern Med 2020, April 2. DOI: https://doi.org/10.7326/M20-1376
Thoughts about how to communicate as a clinician in this crisis. Talking maps for communication tasks that none of us have faced before, including facilitating virtual goodbyes between family members and dying patients with restricted access. And explaining decisions on why a particular patient will not receive a scarce resource: “I can see how it feels unfair”. Phew. Could anyone ever have imagined that?
Procedures
Zhang Y, Zhang X, Liu L, Wang H, Zhao Q. Suggestions for infection prevention and control in digestive endoscopy during current 2019-nCoV pneumonia outbreak in Wuhan, Hubei province, China. Endoscopy. 2020 Apr;52(4):312-314. PubMed: https://pubmed.gov/32212122. Full-text: https://doi.org/10.1055/a-1128-4313
Brief workflow to prevent SARS-CoV-2 transmission in the endoscopy center.
Diagnostics
Qiu L, Liu X, Xiao M, et al. SARS-CoV-2 is not detectable in the vaginal fluid of women with severe COVID-19 infection. Clin Infect Dis 2020, April 2, ciaa375, full-text: https://doi.org/10.1093/cid/ciaa375
Is the virus everywhere? No. Not in the vaginal fluid (of 10 women with severe COVID-19).
Saito M, Adachi E, Yamayoshi S, et al. Gargle lavage as a safe and sensitive alternative to swab samples to diagnose COVID-19: a case report in Japan. Clinical Infectious Diseases 2020, April 2, ciaa377, https://doi.org/10.1093/cid/ciaa377
Case report of a patient who did not produce sputum. Gargle lavage testing was sensitive. If confirmed by larger studies, this can be done by patients themselves without putting healthcare professionals at increased risk.