COVID-19 Literature Situation Report February 3, 2020

• H Zhang, et al propose a potential digestive system route of transmission, based on gene expression data related to angiotensin converting enzyme II (ACE2) in human tissues from lung, esophagus, stomach, ileum, and colon. Among ACE2-expressing cells in the tissue types assessed, ACE2 expression was found to be highest in the ileum and colon.

• ACE2 appears to be important in cellular mechanisms of infection by 2019-nCoV and other coronaviruses (e.g., SARS). Patients with 2019-nCov can have GI symptoms. Fecal transmission of SARS CoV was a neglected risk during the SARS epidemic.

• Epidemiologic support for the potential role in transmission is not provided.

Zhang H, et al. (Jan 31, 2020). The digestive system is a potential route of 2019-nCov infection: a bioinformatics analysis based on single-cell transcriptomes. Pre-Print. https://www.biorxiv.org/content/10.1101/2020.01.30.927806v1

• SW Park, et al. assess preliminary basic reproductive number (R0) estimates in several reported modeling approaches. They identify improved information on generation interval (time from when an individual is infected to when they infect another individual) as a key parameter to improve R0 estimates.
• The pooled estimate of R0 constructed using their defined approach is 3.1, with a 95% confidence interval of 2.1-5.7. This wide confidence interval likely reflect uncertainties in the currently available epidemic information.

Park SW, et al. (Feb 2, 2020). Reconciling early-outbreak preliminary estimates of the baseline reproductive number and its uncertainty: a new framework and applications to the novel coronavirus (2019-nCoV) outbreak. Pre-Print. https://www.medrxiv.org/content/10.1101/2020.01.30.20019877v2

• M Hoffman, et al. found that 2019-nCoV uses the same receptor, ACE2, used by SARS viruses to invade host cells; and that another cellular protease may be part of the process, presenting another potential target for therapy. They also consider how similarities with SARS may translate to 2019-nCoV transmission and pathogenicity.
• Sera from a convalescent SARS patient partially inhibited 2019-nCov entry into target cells in vitro.
• Extrapulmonary SARS-CoV spread in ACE2-expressing tissues was observed, and should be assessed for 2019-nCoV. The role of an additional protein (TMPRSS2) in 2019n-CoV entry may affect these comparisons.

Hoffman M, et al. (31 Jan, 2020). The novel coronavirus 2019 (2019-nCoV) uses the SARS-1 coronavirus receptor ACE2 and the cellular protease TMPRSS2 for entry into target cells. Pre-Print.
https://www.biorxiv.org/content/10.1101/2020.01.31.929042v1

• This article provides additional information on a father-son pair from Vietnam, reported earlier

• The father was a 65 year-old with a history of hypertension, type 2 diabetes, coronary heart disease, and lung cancer. 

• • He became ill with fever on 17 January, 2020, and was admitted to hospital through the ED on 22 January. His condition was improving on and after 26 January.

• • He tested positive (RT-PCR) for 2019-nCoV from a throat swab.

• • Chest x-ray showed left lung upper lobe infiltrate, which progressed for a few days and started to resolve in hospital

• • He was treated empirically with antivirals and broad-spectrum antibiotics (unspecified); and on supplemental oxygen due to increasing hypoxia and dyspnea.

• The son was an otherwise-healthy 27 year old with dry cough, fever, loose stools, and vomiting before admission, starting on 20 January (estimated incubation period, 3 days). 

• • He presented at the hospital on the same day as his father (22 Jan) and had normal chest x-ray and labs. He was listed as stable from 23 January on.

• • He also tested positive (RT-PCR) for 2019-nCoV from a throat swab.

Phan LT, et al. (2020). Importation and Human-to-Human Transmission of a Novel Coronavirus in Vietnam. NEJM. DOI: 10.1056/NEJMc2001272