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How Does COVID-19 Compare to Other Viruses?

There are many differences—and some similarities—between the coronavirus that causes COVID-19 and other viruses that lead to infectious diseases like SARS and the flu.

Since the early days of the global pandemic, public health officials, scientists, and infectious disease experts have been racing to understand the coronavirus that causes COVID-19. Research, statistics, and time have revealed a great deal about the new coronavirus disease and its prevention, symptoms, and treatments, but there’s still a lot we don’t know.


While there are many unanswered questions, there is one thing we can be sure of: COVID-19 is unlike any pandemic disease we have seen. So, how does SARS-CoV-2, the coronavirus that causes COVID-19, compare to other viruses? Let’s take a look.

How Is COVID-19 Different From SARS?

It’s important to note that while COVID-19 may be new, coronaviruses are not. Coronaviruses are a large family of viruses that can cause the common cold and other illnesses. This is also not the first time a coronavirus has caused a major disease outbreak.

Severe acute respiratory syndrome (SARS) spread around the globe from 2002 to 2003. There are many similarities between COVID-19 and SARS. Both are caused by coronaviruses that can lead to severe respiratory illness. Even the names of the viruses that cause the two diseases—SARS-CoV (the SARS virus) and SARS-CoV-2 (the COVID-19 virus)—sound similar. However, there are some key differences between the two coronavirus diseases.

A notable difference between the two diseases is that COVID-19 has infected many more people than SARS. During the 2002–2003 SARS outbreak, there were 8,439 confirmed cases.1 As of August 2020, the number of COVID-19 cases worldwide had climbed well over 23.5 million.2

One theory why the new coronavirus is more widespread than SARS is that people with COVID-19 can infect others up to three days before symptoms start,3 whereas people with SARS are only contagious when they have symptoms.4 This can make it difficult for public health workers to trace the virus and prevent community spread of COVID-19.

COVID-19 and the Flu

Isn’t COVID-19 just another flu? The experts say no. For starters, the two respiratory illnesses are caused by completely different types of viruses. The flu is caused by influenza viruses, not a coronavirus. While the flu and COVID-19 may have similar symptoms—such as fever, cough, chills, and fatigue—COVID-19 differs from the flu in some very important ways:5

  • A person with COVID-19 may also have other signs, like loss of taste or smell.
  • It can take two to 14 days for a person with COVID-19 to show symptoms (or they may never show symptoms at all). A person with the flu will typically show symptoms one to four days after infection.
  • People with COVID-19 can be contagious for a lot longer (two days before symptoms and up to 10 days after infection) than someone with the flu (one day before symptoms and typically three to four days into the illness).
  • COVID-19 is more likely than the flu to spread quickly, easily, and continuously through superspreader events.
  • There is no vaccine for COVID-19.

The new coronavirus disease also has a higher death rate than the flu. As of August, the COVID-19 mortality rate in the U.S. was just over 3%, which equates to over 179,000 deaths since January.6 The death rate from the seasonal flu is much lower at an estimated .1%7—or 12,000 to 61,000 deaths annually.8

While the seasonal flu is a public health concern that affects millions each year, COVID-19 is clearly more dangerous and a major threat to the health of the U.S. population.

Interested in Public Health Career? Earn a Master’s Degree Online

Do you want to help in the fight against COVID-19 and tackle other pressing issues affecting population and community health? Consider advancing your college education with a public health degree. By earning an Master of Public Health (MPH) degree online, you can learn to address pressing global public health challenges ranging from virus outbreaks to the opioid crisis.

A master’s in public health can position you for many rewarding career opportunities and boost your salary potential. With your master’s degree, you could pursue a job as a public health analyst, epidemiologist, community health worker, or other public health professional in a nonprofit or government agency.

If you’re passionate about teaching people how to be healthy, an online MS in Health Education and Promotion degree might also be a great choice for you. As a health educator, you could design and lead health education programs that have a community or even global impact on the health of others.

Walden University is an accredited institution that offers Master of Public Health and MS in Health Education and Promotion degree programs online. Expand your career options and earn your degree in a convenient, flexible online learning format that fits your busy life.

Walden University is accredited by The Higher Learning Commission,