Australian children aged six months to five years old could soon be rolling up their sleeves for a COVID-19 jab.
On Tuesday, Australia's national medical regulator, the Therapeutic Goods Administration (TGA), announced Moderna's COVID-19 vaccine could safely be given to young children in doses one-quarter the size of that approved for adults.
It's the first time in Australia a COVID-19 vaccine has been provisionally approved for this age group.
But federal health minister Mark Butler stressed the TGA's decision was "just the first step in a process".
So does this mean I get my child vaccinated now?
Not quite.
While the TGA has given Moderna's paediatric vaccine the green light, the nation's top vaccine advisory body — the Australian Technical Advisory Group on Immunisation, or ATAGI — still needs to provide recommendations on its use to the government.
Chris Moy, vice-president of the Australian Medical Association, told the ABC: "We still have to wait for ATAGI … to determine whether it's best used for all children in that age group, or whether it's a situation where it would be targeted."
ATAGI will consider the scientific data provided by Moderna to the TGA, along with international evidence and local epidemiological data.
How soon could it be available?
ATAGI is expected to provide its advice to the government "in the coming weeks", but Mr Butler said even if ATAGI recommended the jab, vaccine supplies were currently "very limited".
"As you can imagine, there is fierce competition by countries in North America, Europe and other parts of the world," he said.
"My department is in active negotiations right now with Moderna for Australia to secure as many doses as we possibly can."
Mr Butler warned parents not to try to book their children in for the vaccine just yet.
"I want to stress in spite of this good news … there is no action yet that can be taken by parents."
How many jabs will kids get, and how far apart?
The TGA recommends the vaccine be given as two doses, 28 days apart.
For young children who are immunocompromised, it recommends a third dose at least 28 days after the second.
Moderna's paediatric vaccine is made in the same way as the vaccine for adults; however, it contains a lower concentration of the active ingredient.
How do we know the vaccine is safe?
The TGA said it made its decision by carefully considering data from a trial in the US and Canada — called the KidCOVE clinical trial — which included over 6,000 participants aged six months up to six years old.
"The study demonstrated that the immune response to the vaccine in children was similar to that seen in young adults (18-25 years) with a favourable safety profile," it said.
Common side effects included things like fatigue, pain at the injection site, irritability and crying. Reactions were generally mild to moderate and disappeared after a couple of days.
Importantly, no children in the trial developed heart issues like myocarditis (seen in rare instances in older age groups), and there were no other serious adverse events reported.
Infectious disease physician Robert Booy said real-world evidence also showed the vaccine had a good safety profile.
"The new vaccine has already been used in hundreds of thousands of children in the United States, and the safety reports from there are reassuring," said Professor Booy of the University of Sydney.
If the vaccine is approved by ATAGI, it will be closely monitored by health authorities, and Moderna will be required to continue providing safety and efficacy data to the TGA (from ongoing trials and the vaccine's real-world rollout).
What's the benefit of vaccinating young kids?
The clinical trial showed the vaccine prevented symptomatic COVID-19 infection at a rate of 51 per cent in children between six months and two years, and 37 per cent in children two to five years old.
"As we have seen with children in older age groups, the TGA expects that vaccines for younger children will provide protection from the most severe outcomes of COVID-19, such as hospitalisation and death," the TGA said.
While COVID-19 is much less risky for kids than it is for adults, high levels of infection in the community are leading to significant disruptions to kids' schooling, childcare and other activities, paediatrician Daryl Cheng said.
"The expansion of COVID-19 vaccines to young children will be a welcome relief for many concerned parents and families," said Dr Cheng of the Murdoch Children's Research Institute.
He said although children were less likely to experience complications from COVID-19, severe disease could sometimes happen, including in previously healthy children.
"Children are also at risk of a rare but potentially severe COVID-19 complication known as multi-system inflammatory syndrome," he said.
"We know that vaccination helps to protect children from this life-threatening condition."
Professor Booy said COVID-19 vaccination was particularly important for children with disabilities and chronic medical conditions.
"These are the groups that benefit most from being vaccinated," he said.
Professor Booy added that vaccinating young children had the added benefit of helping to protect those around them.
"Very young children can transmit infections they catch at day care to their parents, to teachers, and to vulnerable grandparents."
What if my child has already had COVID-19?
COVID-19 vaccines are still recommended for people who have had COVID-19, because vaccination helps to boost protection levels overall.
This combination of natural and vaccine-induced immunity is known as "hybrid immunity".
According to the World Health Organization, the protection afforded by hybrid immunity is stronger than that provided by either vaccination or infection alone (though it's unclear if this protection persists with newer COVID variants).
ATAGI currently recommends a three-month interval between infection and subsequent vaccination. This is to optimise protection against severe disease.
