Coronavirus infection rates have dropped in Victoria, but Mildura is an exception.
About one per cent of residents in the rural city have the virus — the second-highest rate of active cases per capita behind Ballarat.
Loddon Mallee Health Network director Bruce Bolam said there were almost 3,000 active cases across the Bendigo, Mildura, Echuca and Swan Hill regions.
"We've been getting 300 to 400 cases per day, on average, over this and last week," he said.
"Mildura is accounting for … around 100 a day.
"People aren't following the numbers these days, but around half a percentage of those cases do often result in very severe disease and potentially hospitalisation."
Boosters 'absolutely critical'
Dr Bolam said the rates remained high in Mildura because the rise of Omicron during the holiday season coincided with a local spike in Delta infections.
"Third boosters are absolutely critical, both to slowing the rate of passing it on, and stopping the risk of more severe disease," he said.
"We have been playing catch-up with those boosters, and now primary school aged children are getting vaccinated in large numbers, but it is far from the case that everybody has had both their boosters or that their children have been vaccinated.
"That basically means there is a significant potential for transmission to occur in the community and that's what's driving those 100-odd cases each day."
Forty-five per cent of postcode 3500's population has had three doses of a vaccine.
Mildura South Primary School principal Marie Therese Milani says her school has had a "steady flow" of COVID cases, which have forced siblings and teachers to isolate for 7 days in addition to the positive cases.
But she said the requirement that students be tested twice a week was helping.
"I'm really grateful we have this resource for our families, because it gives families a message that we care," Ms Milani said.
"People are testing and sharing their results, and we're providing the safest, cleanest environment at school because we have the resources to do it."
