After initially preying on the old and vulnerable, there is increasing fear Covid is morphing into a disease which hunts the young.
High immunisation in the older population makes young people the softest target for the Delta variant.
Attention is turning to vaccinating teenagers, as an outbreak in Canberran schools, and the death of a 15-year old with Covid in Sydney brings the danger into sharp focus.
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And with children aged nine or younger accounting for nearly a quarter of Victoria's active infections, director of the National Centre for Immunisation Research and Surveillance Kristine Macartney warned Delta had "changed our thinking" on vaccinations in children.
"Adults are increasingly protected and children are vulnerable. Delta being so transmissible is largely why we are now turning our focus and seeing children and teens implicated in the pandemic much more," she says.
What's available and when?
The Pfizer jab was approved for children aged 12 to 15 this month, but not all have been immediately added to the rollout.
Immunocompromised children in that age bracket, those with an underlying health condition, and Aboriginal and Torres Strait Islander children began receiving Pfizer last week. By Sunday, 3163 had received a first dose.
The government's Operation Covid Shield plan also flags in-school vaccination by December, but that's not confirmed.
Health Minister Greg Hunt also said there was a "good chance" the Moderna jab, approved for Australian adults last week, would get the green light in the 12 to 18 bracket within a month.
Are there ethical concerns?
Authorities weigh the threat of Covid against complications from the vaccine. That's why AstraZeneca was still recommended for over-60s, even when younger people were told to avoid it if possible.
But vaccinating children, who face a much smaller chance of dying from Covid, to protect the broader community poses an ethical dilemma.
Professor Macartney conceded that was a real concern. But she said Delta's increased transmissibility posed a growing threat to children, with more infections inevitably leading to more deaths.
"It's been a game-changer. When we were facing the original variants, whether we would need to vaccinate children was a bit more uncertain," she said.
"It's really important that we take into account how adolescents might feel about being involved in transmission of the virus as well."
What's happening elsewhere?
Israel has been vaccinating young teenagers since June, after one of the world's most efficient vaccination rollouts. But Delta quickly spread through schools in the country, where children aged 12 to 15 accounted for a third of all cases.
Teenagers in France, Ireland, and the US have already begun receiving the jab. But in the UK, 12- to 15-year-olds were only eligible if they had underlying medical conditions or lived with an immunocompromised person.
Should teachers be forced to get the jab?
Vaccines will become mandatory for aged care workers in September, and there's talk of expanding the list of professions required to get the jab.
While the Delta strain has increased transmission among children, adults remain the most likely spreaders in school settings.
The ACT Australian Education Union said it was too soon to be talking about mandatory vaccinations while many teachers were not even eligible for their first dose.
"The vast majority of school-based staff are very keen to get vaccinated to protect themselves, their loved ones and their students," the AEU's Peter Judge says.
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