Australian measles vaccine advice reviewed as research suggests earlier jabs

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3 days ago

Some Australian babies could face an increased risk of measles infection because of current vaccination guidelines, according to new research which suggests babies as young as four months may need to be vaccinated.
The research lands as Australia's official vaccine advisory body, the Australian Technical Advisory Group on Immunisations (ATAGI), reviews existing measles vaccine recommendations.
Every region of the world is experiencing a major escalation in measles infections, which has prompted ATAGI to launch the review of Australia's two-dose schedule.
In Australia, a first dose is recommended at 12 months of age and a second at 18 months.
An early, additional dose can be given at six months in specific situations, such as when a child is travelling to a country where measles is endemic.
But new research suggests that might even be too late.
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The Murdoch Children's Research Institute (MCRI) has called for authorities to urgently consider whether the first measles vaccine should be recommended at four months of age.
Historically, children in their first year of life were thought to be protected from measles by maternal antibodies. These are transferred from mother to child through the placenta during pregnancy and provide temporary protection against the virus.
But data has emerged showing these antibodies wane before children become eligible for vaccination, which creates a gap in immunity.
MCRI researchers recently published a paper in the Journal of Infectious Diseases, which analysed data from more than 8,000 babies under nine months of age from over 30 low and middle-income countries including China, India, Turkey and South Africa.
They found 81 per cent of babies had measles antibodies at birth, but 70 per cent had zero remaining antibodies by the time they were just four months old.
Only about 18 per cent of the babies had antibodies at seven months.
"In most countries, the number of children who have lost their immunity by three months is very substantial," said Professor Kim Mulholland, who specialises in paediatric immunology and was involved in the research.
Previous research showed some babies in Belgium had an absence of measles antibodies as early as two months old, while antibody protection in Dutch babies lasted for about 3.3 to 5.3 months.
A four-month dose is already recommended in New Zealand as a prevention tool during outbreaks.
Measles is a highly contagious airborne virus and lower vaccination rates combined with increased global travel has led to a surge in cases globally.
This year, 77 cases have been recorded in Australia so far, compared to the 57 recorded for the whole of 2024.
This upward trend comes as vaccination rates among Australian children reach "critical levels" and, in some cases, have dropped below the threshold needed for herd immunity.
A spokesperson for the Department of Health and Aged Care said ATAGI was "closely monitoring" the situation and international evidence to inform any updates to vaccine recommendations.
The ATAGI review would "ensure that timing and number of doses continues to provide the most effective protection for infants", they said.
Professor Mulholland said Australia's immunisation coverage was still stronger than a lot of other countries and an earlier dose would be most critical in countries like Vietnam, where there were currently high infection numbers among young children.
Infections are more deadly in children under the age of one and there is also the risk of a phenomenon called immune amnesia — where the immune system forgets how to fight infections it has acquired before.
Immune amnesia is not a risk for people protected by the measles vaccine.
Willingness to get an extra, earlier vaccine could be low among some groups given the rise of vaccine hesitancy, fuelled by fears about safety and efficacy.
There are also some trade-offs to administering an earlier vaccine.
Some reports suggest an early dose could be associated with a more rapid decline in antibody levels — so by the time a child is four or five years old they might have lower protection than if they waited longer to receive their first dose.
"But measles in a child who has had a vaccine and then has declining antibodies is not as serious at that age, [however] they might circulate it and give it to younger infants who are higher risk," Professor Mulholland said.
Archana Koirala, a paediatrician and infectious diseases specialist at the University of Sydney who was not involved in the research, agreed an earlier vaccine had a role to play during outbreaks.
She said that was made more relevant due to young adults today having lower levels of antibodies than those in past decades.
Research on blood donors published last year found older Australians had much higher levels of measles antibodies than younger adults, because they had grown up during a time when more measles was circulating.
"Pregnant women [are now] starting with a low antibody titre [volume], thus less transfer to their infant resulting in faster decay of immunity in infants," Dr Koirala said.
Dr Koirala said the arguments for a four-month vaccine had merit, but there were already a lot of kids not keeping up with the recommended vaccinations.
"A lot of people aren't aware that if you're going anywhere overseas you should get your baby vaccinated [against measles] from six months," she said.
Measles importation after international travel is the most common cause for infections in Australia.
Professor Mulholland said Australia needed to make bigger efforts to improve immunisation globally, especially after the US withdrew funding of critical vaccine supply in developing nations.
"Measles elimination is possible but it has to be global … Australia is not a country that's been particularly generous when it comes to foreign aid — it's probably time to change that position."