Public health expert: Fast tests key to halting second wave

Scotland’s contact tracing system will be useless unless test results come back more quickly, according to a public health expert.

Professor Devi Sridhar, who advises the Scottish Government on its response to the crisis, said some people aren’t told they have the virus until two days after they are tested.

That means contact tracers tasked with alerting close contacts that they must isolate are on the back foot.

The academic, who is professor and chair of global public health at the University of Edinburgh, said: “The concern is on speed of testing and getting results to people. We need to get that down to less than a day. If it’s longer than 48 hours, it becomes almost worthless to do contact tracing because you can’t catch people fast enough.

“The system relies on being able to catch 60% to 80% of the contacts people have been exposed to.

“It has to happen within three days for it to be successful. If it takes too long you tip into community transmission.”

Professor Sridhar said winter will be the big test for the strategy.

She said: “Hopefully we can get the testing and tracing in place as the lockdown measures ease, have the summer to build it up and hopefully be in a good place by autumn, as we go into winter which will be the next real test of the system.

“We would be remarkably lucky not to have a second wave.”