“Infectious disease researchers at The University of Texas at Austin studying the novel coronavirus were able to identify how quickly the virus can spread, a factor that may help public health officials in their efforts at containment. They found that time between cases in a chain of transmission is less than a week and that more than 10% of patients are infected by somebody who has the virus but does not yet have symptoms.” [1] Or may not ever develop symptoms!
Professor Meyers and her team studied a total of 450 infection reports from 93 Chinese cities and “found more than one in 10 infections were from people who had contracted the virus but were not feeling sick.” [2]
The speed of an epidemic depends on two things:
- how many people each case infects (the reproduction number, R0)
- how long it takes for infection between people to spread (the serial interval). A short serial interval is harder to control.
“This provides evidence that extensive control measures including isolation, quarantine, school closures, travel restrictions and cancellation of mass gatherings may be warranted,” Meyers said. “Asymptomatic transmission definitely makes containment more difficult.”
The research was funded by the U.S. National Institutes of Health and the National Natural Science Foundation of China.
On April 2, 2020 – The CDC report on a study out of 243 cases in Singapore showing coronavirus transmission can occur 1 to 3 days before symptoms show. [3, 4]