The duty of care is enshrined in statute; clearly.
The problem here is that the duty of care requires action only where there is a perceived threat which, until our government declares that this is the case, will negate the need for a duty of care. Until that changes we will see our borders remain open. Compounding this is the virtual certainty that we now have potentially thousands of people moving through our country who have had contact with those who may be hosts to this virus.