An empty street is seen amid the COVID-19 pandemic in Melbourne, Australia, on May 28, 2021. Australia has seen the COVID-19 vaccine doses administered surpass 4 million, almost two months after the government's initial deadline for the target. (Photos: Xue Bai/Xinhua)

People wait outside a COVID-19 vaccination center in Melbourne, Australia, on May 28, 2021. Australia has seen the COVID-19 vaccine doses administered surpass 4 million, almost two months after the government's initial deadline for the target.

An empty street is seen amid the COVID-19 pandemic in Melbourne, Australia, on May 28, 2021. Australia has seen the COVID-19 vaccine doses administered surpass 4 million, almost two months after the government's initial deadline for the target.

People wait outside a COVID-19 vaccination center in Melbourne, Australia, on May 28, 2021. Australia has seen the COVID-19 vaccine doses administered surpass 4 million, almost two months after the government's initial deadline for the target.

A COVID-19 notice is seen in Melbourne, Australia, on May 28, 2021. Australia has seen the COVID-19 vaccine doses administered surpass 4 million, almost two months after the government's initial deadline for the target.