Sydney coronavirus outbreak sparked by selfish elderly couple who refused to isolate surges to four including a musician who s performed gigs all over the city - with 250,000 residents urged to get tested even if they have a bit of a cough
Four mystery coronavirus cases have emerged in Sydney s Northern Beaches
Close contacts must self-isolate and cannot mingle for Christmas or NYE
There are no known links to other confirmed Covid cases yet, NSW Health said
Three cases were identified in one day prompting border and travel questions
Premiers remain cautiously optimistic they can keep borders open in future
But QLD and WA could close borders again to protect residents from outbreaks