An-Najah News - In the journal, Emerging Infectious Diseases, funded by the U.S. National Institutes of Health and the National Natural Science Foundation of China a team of scientists from the United States, France, China and Hong Kong were able to calculate what's called the serial interval of the virus. To measure serial intervals, scientists looked at the time it takes for symptoms to appear in two people with the virus: the person who infects another, and the infected second person.

Researchers found that the average serial interval for the novel coronavirus in China was approximately four days. This is also among the first studies to estimate the rate of asymptomatic transmission.

The speed of an epidemic depends on two things -- how many people each case infects and how long it takes for infection between people to spread. The first quantity is called the reproduction number; the second is the serial interval. The short serial interval of COVID-19 means emerging outbreaks will grow quickly and could be difficult to stop, the researchers said.
This provides evidence that extensive control measures including isolation, quarantine, school closures, travel restrictions and cancellation of mass gatherings may be warranted," "Asymptomatic transmission definitely makes containment more difficult."

The research pointed out with hundreds of new cases emerging around the world every day, the data may offer a different picture over time. Infection case reports are based on people's memories of where they went and whom they had contact with. If health officials move quickly to isolate patients, that may also skew the data.