Coronavirus History

The coronavirus is a type of virus that typically causes the common cold. However there have been deadly outbreaks of similar viruses in the past. You may recall the 2002–04 SARS outbreak caused by the severe acute respiratory syndrome coronavirus (SARS-CoV) or the 2012 Middle East respiratory syndrome coronavirus outbreak caused by the Middle East respiratory syndrome-related coronavirus (MERS-CoV). This most recent outbreak is the result of a novel new coronavirus, Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This new virus is very similar to the original 2002-04 SARS-Cov virus. The new disease caused but SARS-CoV-2 is called COVID-19.

Should we be Alarmed?

We still aren’t sure just how contagious SARS-CoV-2 is, and since it is a new virus there is no prior immunity in the population. This means that everyone is susceptible to getting the virus and passing it along to others. As with the more well known seasonal influenza, the high-risk groups include older adults and people with underlying health conditions – who may be more likely to develop more severe cases of COVID-19.

If we are able to contain this outbreak, it is possible that we can prevent SARS-CoV-2 from taking root in the population, as other respiratory diseases such as seasonal influenza have.

Most cases of COVID-19 have been mild. Of what we know so far about global cases, an estimated 3.4% have died, but it is largely dependent on location. In the epicenter of the outbreak – Hubei Province, China the mortality rate is 4.2% but it is only 1.6% outside of China. These numbers are likely to change as the outbreak progresses.

As of March 6, 2020 more than 101,600 people have been reported infected worldwide, and 3,460 have died. As a comparison, the 2002-2004 SARS outbreak infected 8,000 people worldwide but killed 774 (nearly 10%). MERS-CoV is even more deadly with a mortality rate of nearly 30%.

Symptoms of COVID-19

The symptoms of COVID-19 are very similar to that of the flu, and may include any of the following:

  • Dry cough
  • Shortness of breath
  • Fever

Other respiratory illnesses, caused by the likes of rhinoviruses, enteroviruses and other viruses, don’t necessarily have fever, says Preeti Malani, an infectious disease specialist at the University of Michigan School of Medicine in Ann Arbor. Colds often include a runny nose, but that hasn’t been a symptom for COVID-19. Though many people infected with SARS-CoV-2 will probably experience mild symptoms, others can develop pneumonia.

How do people die from COVID-19?

Coronaviruses usually cause fairly mild illness, affecting just the upper airway. But the new virus, like those behind SARS and MERS, penetrates much deeper into the respiratory tract. SARS-CoV-2 leads to “a disease that causes more lung disease than sniffles,” says Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases in Bethesda, Md. And damage to the lungs can make these illnesses deadly.

Patients with the disease generally die from respiratory and multiorgan failure, partially caused by the virus but also their own immune responses. During infection, the virus that causes COVID-19 attacks cells within the respiratory tract, particularly the lungs. As these cells die, they fill the airway with fluids and debris while the virus continues to replicate — making it hard to breathe.

How long is the incubation period?

The disease’s incubation period is the amount of time from being exposed to the virus to showing symptoms. Officials estimate that’s about five days, but may be as short as two and as long as 14 days.

How long are people contagious?

The contagious period may begin before symptoms show and may last even after symptoms go away. Some published studies and some research that hasn’t yet gone through peer review suggest that period could be one to 29 days.

How does the disease spread?

Coronaviruses like SARS and MERS — and now SARS-CoV-2 — probably spread between people similar to other respiratory diseases, the U.S. Centers for Disease Control and Prevention says. Respiratory droplets from an infected person’s cough or sneeze can carry virus to another person standing almost six feet away.

Touching surfaces covered with droplets and then touching your face can also spread the virus. (Researchers aren’t sure how long the virus stays on surfaces. It’s likely a few hours but could possibly be days.) A report from the Chinese Center for Disease Control and Prevention also suggests that the virus might spread through feces as well.

Unlike SARS and MERS, there is also evidence that the new coronavirus can be spread by people with no or very mild symptoms. Asymptomatic transmission is common for contagious viruses such as influenza or measles.


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