A surge in Covid-19 cases in Australia’s second-biggest city could take weeks to subside despite a lockdown and orders to wear masks, Australia’s acting chief medical officer has said as the country braces for a second wave of infection.

Australia’s Acting Chief Medical Officer Paul Kelly said it would take “weeks” to slow the outbreak to levels seen as recently as June, when Victoria and the rest of Australia reported single or double-digit daily infections.

“We have learned over time that the time between introducing a measure and seeing its effect is at least two weeks and sometimes longer than that,” Kelly told Australian Broadcasting Corporation radio.