It depends upon the background prevalence of the virus in the population. When it's very rare, then it probably doesn't make a lot of sense by the numbers. When things are much more common, or if you're still a bit uncertain, then it probably makes some sense. I think that change in the prevalence within the population was in part underlying the change in recommendations that came out from PHAC. We don't do it in the hospital on a daily basis, but as the prevalence changes then we start to do it.
I think we're still in a grey area about whether it's helpful or not, but I would be cautious in moving away from the current policies.