A British man who became infected with coronavirus during a trip to Singapore appears to have infected at least seven other people in England, France and Spain, raising concerns that he could be what scientists call a “super spreader.”
The man, whose identity has not been released, appears to have passed the disease to at least seven others, possibly at a ski resort in Switzerland.
There are fears the man may have spread the virus to 189 passengers and crew on an easyJet flight from Geneva to London on Jan. 28.
The news of the Brighton, England, resident’s link to the illness in others comes a few days after health officials in China said a patient in Wuhan, China, appears to have infected 14 health care workers in a hospital there.
The rate at which a person infected with a virus spreads the disease varies depending on how contagious a disease is. Researchers believe that in the case of the coronavirus, a person with the disease will infect approximately 2.6 people.
So what explains one person infecting so many?
Here’s a look at super spreaders and what part they play in the spread of the coronavirus.
What is a super spreader?
For various reasons, certain people spread the disease at a much faster rate.
"Whether someone is a super spreader or not will depend on some combination of the pathogen and the patient’s biology and their environment or behavior at the given time,” McGraw said.
“And in a society with so much global connectivity, the ability to move pathogens rapidly across great distances, often before people are even aware they are sick, helps create environments ripe for super spreading.”
McGraw also cites the 20/80 rule that when applied to the transmission of infectious diseases says that a small group of people (20%) is usually responsible for causing over 80 percent of all cases of the disease.
Who are super spreaders?
According to McGraw, super spreaders can be those who appear sick or those who are sick but have no symptoms.
It’s a matter of a person’s makeup, his environment and his habits.
“Whether someone is a super spreader or not will depend on some combination of the pathogen and the patient’s biology and their environment or behavior at the given time,” McGraw said.
“Some infected individuals might shed more virus into the environment than others because of how their immune system works. Highly tolerant people do not feel sick and so may continue about their daily routines, inadvertently infecting more people.
"Alternatively, people with weaker immune systems that allow very high amounts of virus replication may be very good at transmitting even if they reduce their contact with others. Individuals who have more symptoms – for example, coughing or sneezing more – can also be better at spreading the virus to new human hosts,” McGraw explained.
Are super spreaders only seen in the coronavirus?
No, super spreaders have been identified in hundreds of outbreaks of diseases throughout history.
In 2015, a single patient spread the infection to 82 other people with Middle East Respiratory Syndrome, or MERS.
A famous super spreader?
Mary Mallon, an Irish immigrant who worked as a cook for several families in the New York area in the early 20th century, is probably the best-known super spreader.
Mallon, who did not exhibit symptoms of illness, was a carrier of typhoid fever. Through cooking for families who employed here, and for her own family and friends, Mallon passed typhoid fever along to 51 people, earning her the moniker Typhoid Mary.
Most recovered from the disease, but the virus killed at least three people.
Mallon refused to believe that she was responsible for spreading the disease. Eventually, she was arrested and then placed in quarantine where she stayed there for more than 20 years until her death.
What can be done to identify super spreaders?
Discovering who super spreaders are is difficult. If they are identified during an outbreak, it is only after research finds a link between the super spreader and those who have been sickened by the infection.
Werner Bischoff, an infectious disease expert at Wake Forest School of Medicine in Winston-Salem, North Carolina who has studied the spread of respiratory illnesses, says finding the traits of a super spreader is a difficult task.
Of a study he conducted into the spread of influenza, Bischoff told Wired, “We tried to find some risk factors that indicated that someone is a super-emitter. We couldn’t find anything."