At least 18 Covid cases have been linked to 'freedom' protests throughout Melbourne earlier this month.
Ten men and eight women have tested positive to the virus after marching through the streets with up to 20,000 other 'freedom fighters' on November 13 and 20.
Public health officials believe nine of the cases were already infectious when they attended the rally - exposing other attendees to the virus.
Seven others likely acquired their infections while marching, The Age reported.
One of the demonstrators was taken to hospital for Covid treatment, but does not require intensive care. It's understood that patient is not vaccinated.
Crowds gathered on Melbourne’s state parliament steps against Covid vaccine mandates and the Andrews government’s controversial pandemic bill on three consecutive weekends
Just one of the 18 protesters was fully vaccinated, while two had received their first dose.
There are now concerns Covid is spreading undetected throughout attendees at the protests - some of whom mightn't believe the virus exists or will refuse to be tested.
A spokesman for the Victorian Health Department urged anyone who attended the protests to be on alert for symptoms and to 'get tested if they develop even