US coronavirus cases have crossed the 20 million mark as officials seek to speed up vaccinations and a more infectious variant surfaces in Colorado, California and Florida.
South Australia will impose a hard border closure with NSW in response to the spread of COVID-19 cases in Sydney, with officials also keeping their "fingers and toes crossed" in relation to Victoria as cases emerge in Melbourne.
Britain has become the first country to approve a coronavirus vaccine developed by Oxford University and AstraZeneca, hoping rapid action will help it stem a surge of infections driven by a highly contagious variant of the virus.
New Year's Eve restrictions across greater Sydney have been tightened after NSW reported 18 cases of community transmission of coronavirus and a second cluster in the city's inner west.