Victoria is still having a notable number of fresh community cases, and NSW is likely to have a second wave now it is opening up, so it seems reasonable to me for other states to wait at least one 14 day infection period, and maybe two periods or 28 days. That would take us to the end of June.
There has been mention of July 10 as a possible date for the Qld border to reopen, but that would depend on if NSW and Victoria had their community transmission suppressed.
Victorian Premier Dan Andrews seems very cautious about risking a second wave by reopening too early.
NSW is going early, putting a higher priority on economic activity despite the public health risks, so let's see how that goes. Once NSW is suppressed, it may be safer for other states to open up.



in Victoria.



Bookmarks