Victoria’s health boss is still in the dark on the level of COVID-19 vaccination among construction workers as the sector prepares to reopen after a two-week shutdown.

Construction workers in Melbourne and other locked-down areas can return to worksites from Tuesday, as long as they follow strict safeguards and have had at least their first jab.

The industry-wide mandate, and other restrictions brought in to curb transmission, sparked a protest outside the CFMEU’s Melbourne headquarters on September 20, the day the state government announced the sector would down tools for a fortnight-long reset.

Chief health officer Brett Sutton said tens of thousands of construction workers had since come forward to meet the first-dose requirement, but could not say what proportion of the industry is now vaccinated.

“I haven’t asked the question,” he said on Monday.

Professor Sutton believed the building industry was ready for Tuesday’s restart, having learned a “hard lesson” and reflected on compliance issues with masks and tearooms.

“We can absolutely turn it around,” he said.

The return to work comes as Victoria reviews 14-day isolation requirements for close contacts in schools as some regional students headed back to classrooms on Monday.

Professor Sutton confirmed close contact isolation protocols for COVID-positive cases at schools were changing and would depend on the level of exposure and vaccination status among student and teachers.

“The [exposed] class will be the most at-risk contacts, obviously, but other classes won’t necessarily need to quarantine at home,” he said.

“We certainly won’t have the entire school quarantining for a full 14-day period.”

Victoria had another 1377 local cases – the fifth day in a row of four-figure infections – and four deaths on Monday, taking the toll for the current outbreak to 53.

Education Minister James Merlino said 33 VCE students from COVID-19 hotspots were among the new cases, after 8000 were tested in the lead up to Tuesday’s repeatedly rescheduled General Achievement Test.

The students are being contact-traced and will not be able to sit the GAT, but can take their exams at a later date.

The state government also announced repurposed dental vans would be rolled out to administer COVID-19 vaccinations, boosting rates in the state’s Aboriginal and Torres Strait Islander communities.

This week, the first dedicated van will head to locked-down greater Shepparton, which has the largest Indigenous population in Victoria outside of Melbourne.

Some 65 per cent of Aboriginal and Torres Strait Islanders in Victoria have received at least one dose.

That rate is higher than other states but lower than Victoria’s broader population, with 82.8 per cent of residents 16 and over having received their first shot and 52.5 per cent fully vaccinated.

When Victoria hits 70 per cent double-dose vaccination of its 16-plus population, the state’s sixth lockdown will end, with restrictions due to ease further at 80 per cent.

The indicative dates for reaching the 70 per cent (October 26) and 80 per cent (November 5) targets were “more or less the same” as initially forecast, Professor Sutton said.

Melbourne became the world’s most locked-down city on Monday, chalking up 246 days living under stay-at-home orders to surpass the record set by the Argentinian capital of Buenos Aires.

Professor Sutton said the pandemic had been an “awful crisis” but impacted Melbourne more than other Australian cities, citing the sluggish vaccination rollout as partly to blame.

“That is the vulnerability that means you have to have a lockdown to manage potentially catastrophic numbers and catastrophic numbers of deaths,” he said.

-AAP