I'll defer to the experts on that.

But the guidance has been very consistent and nearly unanimous from those experts this whole pandemic: masks and social distancing work. Anecdotally, I haven't had even a cold in the last nearly 18 months, so my own personal experience suggests that masks and distancing are effective at keeping people from getting sick.

Given that the delta variant appears to be even more contagious, I don't know why the guidance would change now if it turns out steps are needed to reduce the strain on the health care system.