By Gabriella Howell

Currently, the SARS-CoV-2 virus is causing immense changes to everyday life around the world. With many countries locked down and numerous air travel bans in place, many people are having to adjust temporarily to a new way of life. It is crucial at the moment to understand the virus so that we can most effectively treat it. Many similarities can be drawn between SARS-CoV-2 and SARS-CoV, seeing as they are both coronaviruses. However, it is the differences that highlight how we can best adjust SARS-CoV treatment and prevention strategies for dealing with the current SARS-CoV-2 pandemic.

Similarities Between SARS and COVID-19

The novel coronavirus (SARS-CoV-2) is in numerous ways similar to SARS-CoV, the virus responsible for the 2003 SARS outbreak. Both viruses have caused major disruption to people’s daily lives. SARS-CoV-2 is currently causing unprecedented changes to many countries, involving educational effects such as school closures and economic effects such as falls in the stock market, similar to the effects of SARS in certain countries. However, SARS only minorly impacted the UK, with just 4 cases, in extreme contrast with COVID-19 cases in the UK currently reaching over 125,800 [1,22]. Both viruses have similar genomes, with the genome of SARS-CoV-2 having an 86% similarity to that of SARS-CoV [2].

Also, they both have the same probable origin: Bats [3]. This has been determined by isolating coronaviruses in bats, and finding that they share a high degree of homology to both viruses [4]. Similarly, both viruses have the same route of transmission, respiratory droplets [5]. However, for both, there have also been reported other forms of transmission, such as blood, and viral shedding via faeces [6]. With both viruses, patients, particularly those with severe diseases, may progress to acute respiratory distress syndrome, where the lungs struggle to provide the internal organs with sufficient oxygen [7]. This typically happens 8-20 days after the onset of symptoms [8]. Symptoms for both diseases include fever, headache, diarrhoea, a dry cough, hypoxia (a deficiency in the amount of oxygen reaching the tissues), and myalgia (muscle pain) [9][10]. Examples of underlying diseases linked to increased vulnerability include cardiovascular disease, diabetes, and hypertension [11]. The severity of both diseases is associated with comorbidity and increased age [12].

Difference Between SARS and COVID-19

Despite these similarities, numerous differences are crucial for effective containment and treatment of COVID-19. Firstly, SARS-CoV-2 has a primary reproduction number of 2-2.5 [13].  In contrast, SARS-CoV has a primary reproduction number of 2-5 [14]. Both viruses having a basic reproduction number more than zero explains why they have developed into pandemics. Furthermore, SARS has an 11% fatality rate, which is higher than that of COVID-19, which is currently estimated to be 3.4% [15][16]. However, the fatality rate varies across the globe, with a 5.16% rate in the United Kingdom, which is significantly less than that of Italy, which is 10.56% [17]. Although it is difficult to be sure at this stage the overall effects of SARS-CoV-2, we can already tell it has a higher trajectory. There were 8098 cases with 774 deaths from SARS overall over 8 months [18]. This is substantially less than COVID-19, with 2,501,156 cases and 171,810 deaths at the time of writing [19]. This suggests SARS-CoV-2 will have an overall much greater impact, especially considering the spread outside of China, the country of origin for both viruses. Only 26 countries had confirmed cases of SARS by the end of the pandemic, primarily in Asia but also including Canada and the United Kingdom [20]. At the time of writing, 185 countries have confirmed COVID-19 cases, with Italy currently having the highest death toll (over 24,000) [21].


Biography: Gabriella Howell is a fifteen year old student from Brighton, England. She enjoys skiing and playing piano. She is currently about to start studying Chemistry, Maths, Biology, and Latin for A-Levels and would like to go on to study Medicine at university.


References:

  1. "SARS (Severe Acute Respiratory Syndrome)". 2020. Nhs.Uk. Accessed March 27. https://www.nhs.uk/conditions/sars/.
  2. Wilder-Smith, Annelies, Calvin J Chiew, and Vernon J Lee. 2020. "Can We Contain The COVID-19 Outbreak With The Same Measures As For SARS?". The Lancet Infectious Diseases, 1. doi:10.1016/s1473-3099(20)30129-8.
  3. Ibid.
  4. Ibid.
  5. Li, R W K, K W C Leung, F C S Sun, and L P Samaranayake. 2004. "Severe Acute Respiratory Syndrome (SARS) And The GDP. Part I: Epidemiology, Virology, Pathology And General Health Issues". British Dental Journal 197 (2): 77-80. doi:10.1038/sj.bdj.4811469.
  6. Ibid.
  7. Wilder-Smith, Annelies, Calvin J Chiew, and Vernon J Lee. 2020. "Can We Contain The COVID-19 Outbreak With The Same Measures As For SARS?". The Lancet Infectious Diseases, 1. doi:10.1016/s1473-3099(20)30129-8.
  8. Ibid.
  9. Sampathkumar, Priya, Zelalem Temesgen, Thomas F. Smith, and Rodney L. Thompson. 2003. "SARS: Epidemiology, Clinical Presentation, Management, And Infection Control Measures". Mayo Clinic Proceedings 78 (7): 882-890. doi:10.4065/78.7.882.
  10. Sun, Pengfei, Xiaosheng Lu, Chao Xu, Wenjuan Sun, and Bo Pan. 2020. "Understanding Of COVID‐19 Based On Current Evidence". Journal Of Medical Virology, 2. doi:10.1002/jmv.25722.
  11. Ibid.
  12. Urso, Domenico Lorenzo. 2020. "Coronavirus Disease 2019 (COVID-19): A Brief Report". Clinical Management Issues 14 (1). doi:10.7175/cmi.v14i1.1467.
  13. "Coronavirus Disease 2019 (COVID-19) Situation Report – 46". 2020. Who.Int. https://www.who.int/docs/default-source/coronaviruse/situation-reports/20200306-sitrep-46-covid-19.pdf?sfvrsn=96b04adf_2.
  14. Wallinga, J. 2004. "Different Epidemic Curves For Severe Acute Respiratory Syndrome Reveal Similar Impacts Of Control Measures". American Journal Of Epidemiology 160 (6): 509-516. doi:10.1093/aje/kwh255.
  15. "Severe Acute Respiratory Syndrome (SARS)". 2003. Eurosurveillance 8 (5): 121-121. doi:10.2807/esm.08.05.00413-en.
  16. "Coronavirus Disease 2019 (COVID-19) Situation Report – 46". 2020. Who.Int. https://www.who.int/docs/default-source/coronaviruse/situation-reports/20200306-sitrep-46-covid-19.pdf?sfvrsn=96b04adf_2.
  17. Zhi. 2020. "[The Epidemiological Characteristics Of An Outbreak Of 2019 Novel Coronavirus Diseases (COVID-19) In China]. - Pubmed - NCBI". Ncbi.Nlm.Nih.Gov. https://www.ncbi.nlm.nih.gov/pubmed/32064853.
  18. Wilder-Smith, Annelies, Calvin J Chiew, and Vernon J Lee. 2020. "Can We Contain The COVID-19 Outbreak With The Same Measures As For SARS?". The Lancet Infectious Diseases, 1. doi:10.1016/s1473-3099(20)30129-8.
  19. Zhi. 2020. "[The Epidemiological Characteristics Of An Outbreak Of 2019 Novel Coronavirus Diseases (COVID-19) In China]. - Pubmed - NCBI". Ncbi.Nlm.Nih.Gov. https://www.ncbi.nlm.nih.gov/pubmed/32064853.
  20. "Severe Acute Respiratory Syndrome (SARS)". 2003. Eurosurveillance 8 (5): 121-121. doi:10.2807/esm.08.05.00413-en.
  21. "Coronavirus: Which Countries Have Confirmed Cases?". 2020. Aljazeera.Com. https://www.aljazeera.com/news/2020/01/countries-confirmed-cases-coronavirus-200125070959786.html.
  22. https://coronavirus.jhu.edu/map.html