Coronavirus and Super-Spreaders: What You Need to Know

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PUBLISHED Jan. 27, 2020

What you need to know about the coronavirus

The outbreak of a new coronavirus in China is continuing to spread.

The new virus, known as Novel Coronavirus (2019-nCoV), is concerning precisely because it’s new. “We are in the very early stages and some of the details and facts we would like to know are not quite available,” says Robert Kim-Farley, MD, professor-in-residence at the UCLA Fielding School of Public Health.

Also of concern is the emergence of potential super-spreaders—people who seem to be more infectious and cause more infections than experts would predict.

Here’s what you should know about the coronavirus, and the role super-spreaders can play in outbreaks.

What is a coronavirus?

Coronaviruses are a family of viruses that can cause various respiratory illnesses, including the common cold. According to a recent article in the Journal of the American Medical Association (JAMA), coronavirus accounts for 10 per cent to 30 per cent of all adult upper respiratory infections.

This group of viruses is actually found more often in animals, including pigs, chickens, ducks and wild birds, according to the Government of Ontario. “What usually happens is that the virus will infect an animal then evolve and infect humans, so there’s potential for human-to-human spread,” says Miriam A. Smith, MD, chief of infectious disease at Northwell Health’s Long Island Jewish Forest Hills in Queens, New York.

There are seven basic types of coronavirus that affect humans. Four usually cause mild illness. Three are more ominous and all jumped from animals, according to the Centers for Disease Control and Prevention (CDC) in the United States. One was severe acute respiratory syndrome (SARS), which originated in China. The other was Middle East respiratory syndrome (MERS), which appeared in Saudi Arabia in 2012. The third is the current outbreak.

Where did the current outbreak originate?

Epidemiologists have traced the current outbreak of illness to a busy seafood and poultry market in Wuhan, the capital of Hubei Province in Central China. According to the JAMA article, Chinese officials announced the outbreak on Dec. 31, 2019.

No one knows which animal might have been responsible for the outbreak, but interest is currently on snakes, says William Schaffner, MD, an infectious diseases specialist with Vanderbilt University Medical Center in Nashville, Tennessee. There’s also some speculation about bats, which is intriguing, says Dr. Schaffner, because both MERS and SARS were ultimately linked to bats.

So far, the outbreak is still centred in Wuhan City, but has moved to other parts of China, and continues to spread throughout the world.

What are the symptoms?

Coronaviruses affect the respiratory system, so symptoms can be similar to the cold or flu. This can include cough, fever, sore throat, runny nose, headache and overall feeling of being unwell, reports the Government of Canada. But symptoms do vary with the current virus mainly showing up as fever, cough, and shortness of breath, says Dr. Messonier.

MERS caused respiratory symptoms (50 per cent to 89 per cent of patients needed help breathing through mechanical ventilation) but also gastrointestinal problems and kidney failure, according to the JAMA article. Like the current coronavirus, SARS patients had fever, cough, and shortness of breath, but some also had watery diarrhea. Up to a third of SARS patients needed mechanical ventilation. Some people with the Wuhan coronavirus have had pneumonia (in which the virus affects the lungs), says. Dr. Messonier.

How serious is the current virus?

Here’s a bit of good news: So far, the new coronavirus does not appear to be as virulent as SARS or MERS, says Dr. Schaffner. The fatality rate for MERS was 36 per cent, and it was 10 per cent for SARS, the JAMA authors stated. The fatality rate for the Wuhan coronavirus stands at about four per cent, says Dr. Messonier, although that will likely change. In general, the deaths have been in people with pneumonia—often the elderly or people who had an underlying medical condition.

“The virus obviously has the potential to kill people,” says Dr. Kim-Farley, who was on loan to the World Health Organization because of previous service as an employee of the CDC for 18 years.

How is the new coronavirus spread?

Scientists are still figuring this out.”The assumption is that the outbreak was initially based on exposure to a live animal market,” says Dr. Smith. “Now the virus appears to be spreading from human to human, but we don’t yet know how or how easily,” she says.

“It’s early days, but the assumption is that transmissibility is going to be somewhere between SARS and MERS,” says Wes Van Voorhis, MD, PhD, director of the Center for Emerging and Re-emerging Infectious Diseases (CERID) at the University of Washington. Although both of these coronaviruses had high mortality rates, SARS was easily transmittable while MERS did not spread as easily, says Dr. Schaffner.

In general, coronaviruses are spread from person to person through respiratory droplets—either through the air or if you touch a surface that has the virus on it, says Dr. Messonier. “Right now, we don’t know if this is how the Wuhan virus is spreading. We also don’t know if you have to be in close, face-to-face contact for it to spread, or if more casual contact is enough,” says Dr. Schaffner.

What is a “super-spreader”?

This term refers to a person (or animal) who can spread the virus more efficiently to other people. “Their cough and sneeze seem to be more effective,” says Dr. Kim-Farley.

The super-spreader label was first coined in 2005 by doctors investigating a SARS outbreak: They used it to describe certain people with the virus who infected an unexpectedly high number of others, forcing epidemiologists to redo their models of expected transmission. Researchers have also found super-spreaders in outbreaks of the MERS, Ebola, and Marburg viruses, among others.

Doctors may have identified a potential super-spreader in the current outbreak: A patient in Wuhan infected 15 healthcare workers in a hospital—which would certainly count as a super-spreader, says Dr. Schaffner. Still, super-spreaders are relatively rare in outbreaks, he adds.

“The assumption is that super-spreaders are a little different immunologically, especially that their innate immunity that helps control the virus,” says Dr. Van Voorhis, who is also director of the Biomedical Interventions Group, part of the Megacenter for Pandemic Diseases Preparedness and Global Health Security, which will be working on vaccines, treatments, and ways to diagnose the new virus. “Super-spreaders have higher virus levels, presumably shedding more virus.”

Bear in mind, though, that the supposed super-spreader in China was ill and in contact with healthcare workers before the virus had been recognized, says Dr. Kim-Farley. “The guard was down, so to speak,” he says.

Can doctors diagnose the virus?

Within two weeks of announcing the outbreak, scientists in China had identified the culprit as a coronavirus and posted the genetic sequence online. Thanks to that quick work, Ontario’s Ministry of Health can now investigate, complete lab tests and do case and contact management to prevent and control further spread of the infection.

Are there treatments or vaccines?

Right now there’s no specific treatment for the new coronavirus, although researchers are racing to develop one. In the meantime, patients are getting supportive care, such as making sure they’re getting enough oxygen and staying hydrated, says Dr. Kim-Farley,

To prevent the spread of the virus, hospitals are relying on isolation and quarantine. Isolation is when a patient with symptoms is put in a negative-pressure room in the hospital (the air pulls in when the door opens instead of out). Those who have been in contact with the virus and are at risk are kept in quarantine, likely staying at home and being monitored by a public health department.

Efforts are also underway to develop a vaccine, according to the National Foundation for Infectious Diseases (NFID).

What are health experts doing?

The World Health Organization convened an emergency meeting on January 22 but decided it was too early to declare a “Public Health Emergency of International Concern,” though members will continue to meet and re-evaluate the situation.

As of January 27, Ontario’s Ministry of Health is meeting with hospitals, paramedics and local public health units near Pearson International Airport to provide further information on federal border screening measures.

What are hospitals doing?

Many, if not most or all hospitals in Canada, have already implemented emergency preparedness measures.

What can you do to protect yourself and those around you?

Based on the information we have now, you should take the same precautions you would take to avoid getting a cold, the flu, or any other infectious diseases year-round. The experts view the virus as a respiratory infection, so follow smart anti-infection practices that you would year-round: “Cover your cough and wash your hands regularly,” says Dr. Messonier.

If you do feel sick, avoid contact with other people and immediately call your doctor.

Watch out for these strange symptoms that can signal a serious disease.