How Coronavirus Compares to SARS and MERS

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Within the coronavirus family, COVID-19 appears to be more easily transmitted but less severe than SARS or MERS.

Like SARS and MERS, COVID-19 person to person transmission is not efficient, as this coronavirus infects the lower lungs making it less transmissible than the flu, which infects the upper airways and nose.” 

While COVID-19 lab-confirmed case numbers soared from about 50 in China to more than 17,000 in at least 23 countries in 3 weeks, the 9-month SARS outbreak only resulted in 8,098 confirmed cases.

Similarly, MERS had been circulating since 2012 with only about 2,500 known cases. However, the higher number of COVID-19 confirmed cases could be due to improved virus detection technologies over recent years.

Although most human Coronavirus infections are typically mild, mortality rates were 10% for SARS and 37% for MERS. In comparison, COVID-19 has a much lower estimated mortality rate of 2%, dropping from a high of 4.1 % in Wuhan to approximately 0.17% elsewhere in mainland China. The factors that cause some COVID-19 infections to be more severe than others still need to be determined.

 

How does Coronavirus compare to Ebola?

The Novel Coronavirus is different from the Ebola virus. Ebola virus is a bloodborne, highly infectious, enveloped filovirus. In contrast, SARS and MERS are from the same family of coronaviruses and have similar physical and biochemical properties and comparable transmission routes to COVID-19. In the absence of COVID-19 specific data, we rely on SARS, MERS, and other coronavirus surrogate data to extrapolate, assess, and manage risk.

Despite differences between the COVID-19 and Ebola, we can adopt many lessons learned from our recent experience with the 2013 to 2016 Ebola outbreak as it relates to risk assessment and risk communication. Table 1 compares what is currently known about the 2019 novel Coronavirus, SARS and Ebola virus.

 

Table 1. Comparing Ebola, SARS, and the novel Coronavirus (download a PDF of this table)

Factor

2019 Novel Coronavirus

SARS

Ebola virus

Etiology

RNA virus from Coronaviridae family

RNA virus from Coronaviridae family

RNA virus from Filoviridae family

Source

Zoonotic

Zoonotic

Zoonotic

Transmission

Direct contact with infected person respiratory droplets

Direct contact with infected person respiratory droplets

Direct contact with infected person blood or bodily fluids

Incubation period

2 to 14 days

2 to 14 days

2 to 21 days

Symptoms

Fever, cough,

shortness of breath or difficulty breathing, diarrhea

Fever, cough, headache, malaise,

shortness of breath, diarrhea

Fever, headache, vomiting, stomach and muscle pain, bleeding, diarrhea

Asymptomatic individuals infective

Yes

No

No

Secondary transmission (fomites)

Unknown

Yes

Yes

Airborne

Unknown

Yes

Yes

Detected in feces

Yes

Yes

Yes

Persistence in wastewater

Likely

Yes

Yes

Effective skin disinfectants

Handwashing with soap and water (min. 20 sec); alcohol-based sanitizer (min. 60%)

Handwashing with soap and water; alcohol based-sanitizer as per manufacturer’s instruction

 

Handwashing with soap and water; (min. 40 sec)  0.05% hypochlorite solution; alcohol-based sanitizer (min. 60%, min. 20 sec)

Effective surface or object disinfectants

Common detergents effective against coronaviruses

Common detergents are effective (e.g., 0.21% hypochlorite, 0.05% triclosan)

0.5% hypochlorite solution and 5% peracetic acid

Webcast: Updates on Novel Coronavirus (COVID-19) for Water Professionals

This webcast, organized by WEF's Disinfection and Public Health Committee (DPHC), is a collaboration between WEF and WRF, and will provide the most up-to-date information available on COVID-19 from some of the most reputable names in infectious disease control and emergency response. It will highlight virus ecology, transmission, control, epidemiology, government agency response, and specific impacts for the water community. Speakers will provide the audience with additional resources and published recommendations, as we continue to learn more about and respond to this ongoing outbreak.

View the Webcast Recording

Authors & Acknowledgements

This article was prepared by the WEF Disinfection and Public Health Committee’s (DPHC) Waterborne Infectious Disease Outbreak Control (WIDOC) Working Group.

  • Rasha Maal-Bared is the Senior Microbiologist at EPCOR Water Services Inc. (Edmonton, Canada) and the current chair of the Waterborne Infection Disease Outbreak Control Working Group.
  • Robert Bastian is a senior environmental scientist at the U.S. Environmental Protection Agency.
  • Kyle Bibby is an Associate Professor and the Wanzek Collegiate Chair in the Department of Civil and Environmental Engineering and Earth Sciences at the University of Notre Dame (Notre Dame, Ind.).
  • Kari Brisolara is the Associate Dean for Academic Affairs and an Associate Professor of Environmental and Occupational Health Sciences at the Louisiana State University Health Sciences Center (New Orleans, La.) and Vice Chair of the WEF Disinfection and Public Health Committee.
  • Lee Gary is an Adjunct Professor at Tulane University, an instructor with the Basic Academy at the FEMA/Emergency Management Institute (Emmitsburg, Md.) and the owner and CEO of Strategic Management Services (New Orleans).
  • Chuck Gerba is a professor of epidemiology and biostatistics in the Dept of Environmental Science at the University of Arizona and a supporting member of the WIDOC working group.
  • Lola Olabode is a Program Director at the Water Research Foundation and an expert in risk management during outbreaks (Washington, D.C.).
  • Naoko Munakata is a Supervising Engineer at the Los Angeles County Sanitation Districts.
  • Robert S. Reimers is a Professor Emeritus at Tulane University’s School of Public Health and Tropical Medicine, the Director of Asepticys Inc. (New Orleans, La.).
  • Albert Rubin is a professor emeritus at North Carolina State University in the Dept of Biological and Agricultural Engineering.
  • Scott Schaefer is the Wastewater Practice Leader with AE2S (Saint Joseph, Minn.) and the Chair of the WEF Disinfection and Public Health Committee.
  • Samendra Sherchan is an Assistant Professor at the Tulane School of Public Health and Tropical Medicine (New Orleans, La.).
  • Jay Swift is a Principal Engineer with Gray and Osborne (Seattle, Wash.).

The authors would like to thank Matthew Arduino (CDC, DDID), Christopher K. Brown (OSHA), Matthew Magnuson (U.S. EPA), Jonathan Yoder (CDC, DDID), and Jill Shugart (CDC, NIOSH) for their comments and feedback. (Note: The conclusions, findings, and opinions expressed by the authors contributing to this piece do not reflect the official position of OSHA, the Centers for Disease Control and Prevention, U.S. EPA, or the authors' affiliated institutions.)

More Resources on Coronavirus

Resources on Coronavirus

 

How Can I Stay Informed?

The organizations below are reputable and reliable sources that are frequently updated.

 World Health Organization (WHO)

Centers for Disease Control and Prevention

Occupational Safety and Health Administration

In an effort to increase transparency and communication, major publishers have created Coronavirus information centers, where relevant and current research is freely available. This includes Springer Nature, Elsevier and Wiley. Several major journals have done the same, including: The Lancet, New England Journal of Medicine and The British Medical Journal.