The Victorian government wants all Year 12 students to be vaccinated against coronavirus before exams in October, but hasn't explained how this will be achieved.
Education Minister James Merlino says the government has made it a "priority" to have all Year 12 students vaccinated before they start exams on October 4 - less than six weeks away.
He said there would be "very strong communication" to students, staff and the wider community to make it happen.
However, the timing is tight, with second Pfizer doses currently being administered up to six weeks after the first. The recommended gap between AstraZeneca doses is 12 weeks.
Mr Merlino would not say whether students would be able to get their second Pfizer dose in three weeks, or if they would be prioritised at the state's vaccination hubs.
"I'm not making any announcements today," he told reporters on Wednesday.
"This is about sending a very strong message to year 12 students, particularly in their final months, giving them confidence and clarity that they can really tackle the last few months of study and give it their best shot."
Mr Merlino also said the state remained hopeful children aged 12 and up could get their first dose of a vaccine by the end of the year, subject to health advice.
It comes as Victoria recorded 45 new locally acquired COVID-19 cases, and the state government's vaccination website crashed as thousands of young people try to secure a booking.
Of the latest cases, 36 are linked to known outbreaks, the source of the remaining nine are under investigation and 28 people were out in the community while infectious.
The total number of active cases in the state is 538.
Health Minister Martin Foley said authorities still had "a lot of work to do" to bring the outbreak under control.
More than 830,000 vaccination bookings over the next four weeks opened from 7am on Wednesday for Victorians aged between 16 and 39, including 450,000 first-dose Pfizer appointments.
Within minutes of bookings opening, the website buckled due to high traffic.
Many people reported receiving a "500 internal server error" after waiting for up to an hour in the queue to schedule an appointment. Others made it through the queue, only to be told they were ineligible for the Pfizer vaccine.
The health department's COVID-19 response deputy secretary Naomi Bromley said the site received 50,000 hits per minute on Wednesday morning, while 1.3 million people had tried to call the coronavirus vaccination booking line.
She pleaded for people to be patient and kind to staff, with more appointments to be made available in coming days.
Opposition health spokeswoman Georgie Crozier said Victorians should be able to book with confidence.
"The state government has had months to get this right and again we see a booking site crash and Victorians left confused," she told reporters.
She also attacked the government's light-on-detail announcement for year 12 students.
"How is this going to be delivered to the tens of thousands of year 12 students? They've been through so much, they've been through lockdowns constantly," Ms Crozier said.
It's not just the state's vaccine booking system facing pressure, with hundreds of staff being furloughed due to coronavirus exposure, the state is importing 350 doctors and nurses from overseas.
The medical professionals are expected to be working across 30 health services by October.
Australian Associated Press
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