COVID-19 & SARS-CoV-2
First published Feb. 13, 2020.
Last updated July 2, 2020 @ 5 pm PT.
The novel coronavirus, SARS-CoV-2, is the cause of COVID-19, a severe acute respiratory disease first detected in Wuhan, China. The spread of COVID-19 is an emerging global health risk that has had a significant impact on the economy and daily lives of people across the globe.
Currently, there are no FDA-approved therapies or vaccines for SARS-CoV-2.
Signs & Symptoms
The Centers for Disease Control & Prevention (CDC) believes at this time that symptoms of COVID-19 may appear in as few as two days or as long as 14 after exposure. Individuals with symptoms including, fever, coughing, and shortness of breath should seek medical advice immediately.1,7 The clinical spectrum of COVID-19 ranges from mild, cold-like symptoms to severe pneumonia, respiratory failure, and in some cases, death.7
Spread of Infection
The WHO has designated the outbreak a global health emergency.3 As of July 2, 2020, there have been 10,940,071 confirmed COVID-19 cases (up 505,236 from June 30). Of the total cases, 5,592,541 individuals have recovered, and 519,575 have died (up 9,796 from June 30), of which 128,684 are from the U.S. (up 1,274 from June 30). The proportion of infected individuals with mild or no symptoms is missing from this data; accounting for this “hidden” data would mean the case fatality rate (CFR) of COVID-19 is lower than current estimates.4
spread of Infection: U.S. Status Report
COVID-19 cases have been reported in all 50 states, with more than 10,000 cases reported in each of 40 states. Local and state governments across the U.S. have implemented social distancing guidelines to prevent community spread. Guidelines included proclamations like WA State’s Stay Home, Stay Healthy order, which required every Washingtonian to stay home unless they need to pursue an essential activity. Since late April, states have started lifting stay-at-home restrictions, although many public health experts caution that this may result in new outbreaks.
Anatomy of SARS-CoV-2
From the beginning of the COVID-19 outbreak, the combination of many expedited studies has revealed an unprecedented amount of information for a new disease, including the causative virus (SARS-CoV-2), its genetic sequence, PCR assays, and serological analyses. Efforts are rapidly ongoing with the aim of quickly designing effective treatments, such as a vaccine or antiviral drug.
SARS-CoV-2 Mechanism of Action
Once in the body, SARS-CoV-2 recognizes and attaches to a transmembrane protein called ACE2 found mainly on cells that line our airways. The effectiveness of SARS-CoV-2 in triggering respiratory disease may be due to the evolved structure of the Spike (S) protein, which contains the receptor-binding domain for ACE2 and creates the virus’s recognizable ‘crown’ shape. After binding to an ACE2 homodimer, the virus enters the cell through a process called receptor-mediated endocytosis. Inside the cell, the virus releases its RNA and takes advantage of the host cell’s machinery, allowing it to reproduce, escape, and continue infecting human tissue.
Situation in Numbers:
How COVID-19 Compares to Other Outbreaks
As more cases emerge, medical professionals and researchers have been able to identify distinguishing traits of COVID-19. Here is a look at other notable viral diseases to show how COVID-19 compares.
- Coronavirus Disease 2019 (COVID-19) – Symptoms. Centers for Disease Control and Prevention. https://www.cdc.gov/coronavirus/2019-ncov/symptoms-testing/symptoms.html. Published April 27, 2020. Accessed April 28, 2020.
- World Health Organization (2020). Novel Coronavirus (2019-NCoV) Situation Reports. who.int/emergencies/diseases/novel-coronavirus-2019/situation-reports/
- Chen N, Zhou M, Dong X, et al. Epidemiological and clinical characteristics of 99 cases of 2019 novel coronavirus pneumonia in Wuhan, China: a descriptive study. The Lancet. 2020.
- “The Urgent Questions Scientists Are Asking About Coronavirus.” The New York Times, 10 Feb. 2020, https://www.nytimes.com/2020/02/10/opinion/coronavirus-china-research.html
- Branswell H. The Coronavirus Questions That Scientists Are Racing to Answer. Scientific American. https://www.scientificamerican.com/article/the-coronavirus-questions-that-scientists-are-racing-to-an swer/. Published January 28, 2020.
- Zhao Y, Zhao Z, Wang Y, Zhou Y, Ma Y, Zuo W. Single-cell RNA expression profiling of ACE2, the putative receptor of Wuhan 2019-nCov. BioRxiv (preprint). 2020. doi:10.1101/2020.01.26.919985
- Centers for Disease Control and Prevention. https://www.cdc.gov/coronavirus/2019-ncov/about/transmission.html. Published January 10, 2020. Accessed March 13, 2020.
- Zhao S, Lin Q, Ran J, et al. Preliminary estimation of the basic reproduction number of novel coronavirus (2019-nCoV) in China, from 2019 to 2020: A data-driven analysis in the early phase of the International Journal of Infectious Diseases. 2020. doi:10.1101/2020.01.23.916395
- @DrewQJoseph AJ, Joseph A, Joseph A, et al. First case of coronavirus spread by a person showing no STAT.
- “Cumulative Number of Reported Probable Cases of Severe Acute Respiratory Syndrome (SARS).” World Health Organization, World Health Organization, 23 July 2015, who.int/csr/sars/country/en/.
- “Middle East respiratory syndrome.” World Health Organization, World Health Organization, emro.who.int/health-topics/mers-cov/mers-outbreaks.html.
- Factsheet about Middle East respiratory syndrome coronavirus (MERS-CoV). European Centre for Disease Prevention and Control.
https://www.ecdc.europa.eu/en/middle-east-respiratory-syndrome-coronavirus/factsheet. Published February 10, 2020. Accessed February 11, 2020.
- Types of Influenza Viruses. Centers for Disease Control and Prevention. https://www.cdc.gov/flu/about/viruses/types.htm. Published November 18, Accessed February 11, 2020.
- “Weekly U.S. Influenza Surveillance Report.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 7 Feb. 2020, www.cdc.gov/flu/weekly/index.htm
- Biggerstaff M, Cauchemez S, Reed C, Gambhir M, Finelli L. Estimates of the reproduction number for seasonal, pandemic, and zoonotic influenza: a systematic review of the literature. BMC Infectious Diseases. 2014;14(1). doi:10.1186/1471-2334-14-480
- Transmission of Avian Influenza A Viruses Between Animals and People. Centers for Disease Control and Prevention. https://www.cdc.gov/flu/avianflu/virus-transmission.htm. Published February 10, 2015. Accessed February 11, 2020.
- Biggerstaff M, Cauchemez S, Reed C, Gambhir M, Finelli L. Estimates of the reproduction number for seasonal, pandemic, and zoonotic influenza: a systematic review of the literature. BMC Infect Dis. 2014;14(1):480. doi:10.1186/1471-2334-14-480
- Fraser C, Cummings DAT, Klinkenberg D, Burke DS, Ferguson NM. Influenza Transmission in Households During the 1918 Pandemic. Am J Epidemiol. 2011;174(5):505-514. doi:10.1093/aje/kwr122
- Morens DM, Fauci AS. The 1918 influenza pandemic: insights for the 21st century. J Infect Dis. 2007;195(7):1018-1028. doi:10.1086/511989
- Lessler J, Reich NG, Brookmeyer R, Perl TM, Nelson KE, Cummings DAT. Incubation periods of acute respiratory viral infections: a systematic review. Lancet Infect Dis. 2009;9(5):291-300. doi:10.1016/S1473-3099(09)70069-6
- Taubenberger JK, Baltimore D, Doherty PC, et al. Reconstruction of the 1918 Influenza Virus: Unexpected Rewards from the Past. mBio. 2012;3(5). doi:10.1128/mBio.00201-12
- 1918 Pandemic (H1N1 virus). https://www.cdc.gov/flu/pandemic-resources/1918-pandemic-h1n1.html. Published March 20, 2019. Accessed March 16, 2020.
- History of 1918 flu pandemic. https://www.cdc.gov/flu/pandemic-resources/1918-commemoration/1918-pandemic-history.htm. Published March 21, 2018. Accessed March 16, 2020.
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