Alex Crozier: Put to the test: use of rapid testing technologies for covid-19
However, several days can elapse between requesting a test and getting and acting on a result, leaving a window in which infection may spread. A further problem is that people may transmit infection before recognising symptoms1—a key driver of spread.
In addition, some people who remain asymptomatic have a similar viral load to those who develop symptoms and may also contribute to spread, although the extent of this is unclear.
123 Given the importance of presymptomatic or paucisymptomatic transmission,1 measures that shorten the time between testing and results are essential for minimising onward transmission. It is difficult to achieve this with large scale PCR testing.