By itself, the test-and-trace approach can reduce the virus' reproduction rate, or R number, by 26 percent, they reported in The Lancet Infectious Diseases, using mathematical models to examine data from previously published studies. The reproduction rate measures the number of people in a population, on average, infected by each person carrying the virus. "Our results show that test and trace can help reduce the R number but needs to be carried out effectively and quickly to do so," he said in a statement. - Herd immunity not close -In the United States and the UK, delays can be even longer. "Test and trace alone won't be enough to control transmission in most communities, and other measures alongside will be needed to bring the R number below 1," said Grassly.

Source: Bangkok Post August 18, 2020 22:52 UTC