COVID-19 vaccines are now approved for children aged from six months up to five years of age, and are already being rolled out to about 70,000 at-risk youngsters.
But what about babies even younger than that? Will there be a vaccine for them? And what role does the vaccination of pregnant people play in the process?
Let's take a closer look at the issues.
What's the risk of severe illness in babies with COVID-19?
Children of all ages can get COVID-19 and experience its complications.
However, as noted by an infectious diseases physician at Monash and Melbourne universities, Michelle Giles, young infants aren't at risk of the severe disease that has been seen with older Australians.
Research published this week in the Medical Journal of Australia looked at children under 16 years of age with COVID-19 between June 1 and October 31, 2021, and found most infections in children were either asymptomatic or associated with mild disease.
The paper found the likelihood of admission to hospital with the Delta variant for medical reasons declined for younger children.
However, that doesn't mean that babies are completely immune from infection.
A study published in July in the New England Journal of Medicine — and funded by the US Centers for Disease Control and Prevention — looked at 537 cases among babies under six months who had been admitted to hospital with COVID-19, and found more than 20 per cent had been placed in intensive care, with 12 per cent needing mechanical ventilation.
Professor Giles notes that study was done in the US, across the Delta and Omicron waves, and looked at children who were already in hospital — as opposed to ones who may have caught COVID-19 and not needed serious medical intervention.
"Some young infants can get very sick from COVID — but that is much more the exception," Professor Giles said.
"By far and away, the majority of infants do not get severe disease from COVID."
How do other vaccines for pregnant people protect babies?
The benefits of maternal vaccination to the infant they are carrying have been known for a long time.
As far back as the 1870s, babies born to mothers who had received the smallpox vaccination were found unlikely to have smallpox early in life.
"When we give a vaccine to the mother, her immune system responds to that vaccine by making antibodies," Professor Giles explained.
"And these antibodies are able to cross the placenta so that the baby has them in its system when its born, so it can be protected straightaway if it gets exposed to that virus."
It's typically a two-for-one deal, with vaccines benefiting both the pregnant person and their unborn baby.
Take the flu vaccine for example. It stops pregnant women from getting severe illness that might require admission to hospital, while offering babies protection.
What about any protection COVID-19 vaccines for pregnant women can offer their babies?
It's a new and evolving area, but some research has suggested that giving vaccines to pregnant people can reduce the risk of hospital admissions and severe illness from COVID-19 for infants under six months.
Remember that study in the New England Journal of Medicine we spoke about earlier?
It found maternal vaccination with two doses of an mRNA vaccine was associated with reduced risk of hospitalisation — including critical illness — among infants younger than six months of age.
That research also found effectiveness was higher when the vaccination occurred after 20 weeks of pregnancy.
"It is promising that it might afford some protection to young infants that can't yet be vaccinated," Professor Giles said.
"And it wouldn't be surprising if this was the case because, as mentioned, we know that this happens with other vaccines that we give pregnant women where they protect the child in the first six months of life."
Should pregnant women delay vaccines to try to increase protection for their babies?
The simple answer is no, they shouldn't.
Professor Giles says it is important women don't delay vaccination, because they themselves need to be protected.
"The risk with delaying vaccination is that while they remain unvaccinated, they're at a higher risk of severe disease, and that is not good for their pregnancy or for their baby," she said.
Will there be a COVID-19 vaccine for babies?
Not in the foreseeable future, if ever.
There aren't any clinical trials running yet for babies under six months of age.
Australia is one of the first countries to roll out the vaccine for children aged six months to five years and, even then, the vaccines are not yet being given to all children, with the vaccine advisory body ATAGI noting there was a low likelihood of severe illness from COVID-19.
So, for the time being, there is one main way to protect babies, according to Professor Giles.
"If we want to give any protection to infants under six months of age from COVID-19, at this stage, there are no vaccines available. So the only way of protecting them is through maternal antibodies," she said.
