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SARS V.S. COVID-19: What's the difference?

The COVID-19 pandemic has been affecting us greatly by dominating the news and restricting our activities as we are under lockdown. Many of you might be familiar with the term SARS, which stands for Severe Acute Respiratory Syndrome. SARS was a coronavirus outbreak in 2003, the first pandemic in the 21st century. The virus that initiated SARS is the virus SARS-CoV, while the virus that causes COVID-19 is SARS-CoV2. It goes without saying that there are also other types of human coronaviruses. Although the names of these two viruses are extremely similar, there are multiple differences between the two of them.

An illustration of the SARS-CoV-2 virus (Centers for Disease Control and Prevention).

What is coronavirus?

Coronavirus can be categorized into branches, as it is a unique but diverse family of viruses. The host range of coronavirus includes a variety of species, but the greatest diversity is often seen in bats. Human coronavirus symptoms include mild respiratory illnesses, also known as a common cold. When an animal coronavirus develops the ability to transmit a disease to humans, a new type of coronavirus can emerge. This transmission is called zoonotic transmission, the travel of germs from an animal to humans like us.

Coronaviruses that are transmitted to human hosts can cause severe illnesses as well as deaths. This is subject to several factors but most importantly our lack of immunity to the new virus. Listed below are examples of different coronaviruses:

  1. SARS-CoV, the virus that caused SARS which was first discovered in 2003 in Foshan, China.

  2. MERS-CoV, the virus which caused Middle East Respiratory Syndrome, first discovered in 2012 in Saudi Arabia.

  3. SARS-CoV-2, the virus that caused COVID-19, first discovered in 2019 in Wuhan, China.

What is SARS?

SARS is a respiratory illness caused by SARS-CoV. The acronym stands for Severe Acute Respiratory Syndrome. The outbreak of SARS initiated in late 2002, ending in around mid-2003. In total, over 8,000 cases were reported and 774 people died from the global outbreak. Similar to COVID-19, the origin of the SARS- CoV is suspected to be bats and it is believed that the intermediate animal host was the civet cat before it was passed onto humans.

The symptoms of SARS

  • Fever

  • Cough

  • Fatigue or malaise

  • Body aches and pains

  • Respiratory symptoms such as:

  • Shortness of breath

  • Serious cases can lead to pneumonia or respiratory distress

Image is courtesy of Fusion Animation.

Similarities Between SARS and COVID-19

They both:

  • Are respiratory illnesses caused by coronaviruses

  • Originated from bats and transmitted to humans via an intermediate animal host

  • Spread by respiratory droplets produced when a person with the virus is in contact with contaminated objects or surfaces

  • Have similar stability in the air and on various surfaces

  • Can lead to potentially serious illnesses and sometimes requiring oxygen or mechanical ventilation

  • Have similar at-risk groups such as older adults or those with underlying health conditions

Differences in Symptoms


  • Common Symptoms: Fever, cough, fatigue, and shortness of breath

  • Less Common Symptoms: Runny nose, headache, muscle aches and pains, sore throat, nausea, diarrhea, chills, loss of taste, and loss of smell


  • Common Symptoms: Fever, cough, malaise, body aches and pains, headache and shortness of breath

  • Less Common Symptoms: Diarrhea and chills

Differences in Transmission

For SARS, most human-to-human infections occurred in healthcare settings where they lacked the infection control procedures. As a result, the outbreak ended once when infection control practices were implemented. The only occurrences since then were through the laboratory accidents and it has not spread throughout the community.

COVID-19 in comparison to SARS is much easier to be transmitted. It appears to spread person-to-person via droplets that are expelled when a person coughs or sneezes and then are inhaled by a nearby person. Transmission is also possible before a person is symptomatic.

Differences in Diagnostics, Vaccines, and Therapeutics

In both viruses, no diagnostics, vaccines nor therapeutics were available at the first stage of its outbreaks. Due to the lack of technology back in 2003, the SARS epidemic experienced setbacks in developing a diagnostic test. Three were invented, one was unreliable while the rest can only be used late in the course of containing the virus.

The development of COVID-19 technology was much faster. In fact, the FDA has approved 235 tests under Emergency Use Authorizations. Vaccines are currently being provided after trials of tests to test the viability.

Differences in Pandemic Duration

The SARS pandemic in comparison to the COVID-19 pandemic was short-lived. From November 2002, the first reported case till the end of the crisis in July 2003, it took only eight months to contain the virus while the COVID-19 pandemic has continued for more than 14 months, researches have also stated that COVID-19 may be around for years.

Although both viruses have their similarities, they also have notable differences, and it is important to stay informed of the distinctions between these diseases. However, hopefully, both of these pandemics will have been things of the past, and we'll be able to learn from our experiences. But for now, we must all follow restrictions, wear our masks, and social distance!


Caldaria, A., Conforti, C., Di Meo, N., Dianzani, C., Jafferany, M., Lotti, T., Zalaudek, I., & Giuffrida, R. (2020). COVID-19 and SARS: Differences and similarities. Dermatologic therapy, 33(4), e13395. https://doi.org/10.1111/dth.13395.

Yuen, K. S., Ye, Z. W., Fung, S. Y., Chan, C. P., & Jin, D. Y. (2020). SARS-CoV-2 and COVID-19: The most important research questions. Cell & bioscience, 10, 40. https://doi.org/10.1186/s13578-020-00404-4.

Chen, X., Yang, Y., Huang, M., Liu, L., Zhang, X., Xu, J., Geng, S., Han, B., Xiao, J., & Wan, Y. (2020). Differences between COVID-19 and suspected then confirmed SARS-CoV-2-negative pneumonia: A retrospective study from a single center. Journal of medical virology, 92(9), 1572–1579. https://doi.org/10.1002/jmv.25810.

Article author: Christine Sun

Article editor: Valerie Shirobokov, Sherilyn Wen