Why are some more infectious than others? Researchers claim that there is such a thing as a "super-spreader" of the coronavirus. They point out the importance of detecting these super-spreaders to prevent situations wherein they immerse themselves in public. Contact tracing for these individuals should also be prioritized than those who are unlikely to spread the infection.
Jon Zelner, an epidemiologist at the University of Michigan, said that being able to differentiate between those who are more infectious and those less contagious could make a tremendous difference in the ease and speed with which an outbreak is contained. He further discussed the importance of contact tracing to those labeled as super-spreaders. On the other hand, those who are the opposite of a super-spreader should not be the focus in terms of contact tracing.
Martina Morris, former professor of statistics and sociology at the University of Washington, adds that there are two factors at play to determine these so-called super-spreaders. The first factor is a link between people, which allows the transmission of infection to take place, and the second factor is how infectious a person is. Admittedly still lacking in information about these factors, Morris pointed out that it can be easy to misattribute multiple infections to an individual when the spread has nothing to do with the person's infectiousness.
However, there still seem to be situations where an individual could spark a massive outbreak. This was evident in the case in South Korea, where a church-goer at the Shincheonji religious group spread coronavirus through the majority of its members.
Dr. Thomas Frieden, former director of the Centers for Disease Control and Prevention and chief executive at Resolve to Save Lives, says that much is still to be investigated about what being a "super-spreader" entails. He adds the possibility of super-spreaders being those with silent infections, oblivious to the fact that they have the virus in them. He further advises the public to avoid crowds and practice proper cough etiquette to prevent super-spreading events.
Super-spreaders Evident From Past Epidemics
The timeline of our civilization's medical history is filled with stories of super-spreading in outbreaks of tuberculosis, measles, parasitic diseases, and other illness. The Ebola outbreak in Africa between 2014 and 2016, for example, revealed that 61% of the infections traced back to just 3% of infected people.
Similarly, in the 2003 SARS outbreak, the first patient in Hong Kong appears to have infected at least 125 others. George Gao, a virologist at the Chinese Centers for Disease Control and Prevention in Beijing, also discussed in a recent paper that the MERS-CoV outbreak in South Korea was driven primarily by three infected individuals.
Zelner admits that although alluring, there are possible dangers in trying to search for viral super-spreaders. Samuel Roberts, a medical historian at Columbia, says that the most important thing for the public at this moment is to find out how to protect themselves. "Finding patient zero is not going to help. It only stokes fear of the other," he adds.
Coronavirus is Found to be Twice as Infectious
Researchers from Los Alamos National Laboratory looked at figures in Wuhan and discovered that the coronavirus passed from 1 person to another between an estimated 2.3 to 3.3 days. This was twice as quickly as previously feared. The study found that 82% of people would need to be immune to stop the spread of infection. Immunity could either be through receiving a vaccine or from recovering from already the disease.
Scientists discovered that the incubation period of the virus is 4.2 days, one day shorter than the previous estimates. The incubation period is described as the period starting from when a person is first exposed to the virus, to the time when they start showing symptoms.
Before January 18 this year, the time from when symptoms first showed in the people affected to the time they were hospitalized was 5.5 days in China. After January 18, the duration shortened significantly to 1.5 days. Scientists claimed this came at the same time as reports of potential human-to-human transmission and the country's boost in emergency response.
China closed off the city of Wuhan on January 23, when it became evident that the virus originated there. However, at 00:50 am on Wednesday, trains operations began running, and major highways also began opening up as China's lockdown on Wuhan was hoisted.
