"As experts in children's health you will have your own views about what needs to happen," said McGregor, who heads the school of social sciences and public policy at Auckland University of Technology.
"But it is clear that complacency and even hostility to immunisation fuelled by social media needs to be strongly countered by medical scientific evidence and persuasive advocacy from people like you."
That led to what role children and young people have in making decisions about their healthcare, she said.
"Take an anti-vaxxer family. How do tamariki, young children, and rangitahi, older youngsters, ensure their best interests are taken into account and their views respected, in line with the Convention on the Rights of the Child. New Zealand, like many other countries, has ratified the children's rights convention.
"Questions such as: is the family sovereign in its opposition to immunisation? And when does the child or the young person have the right to autonomous decision-making? [These questions] are complex, especially as public policy moves towards increased children's autonomy."
McGregor, who wasn't available for interview, also urged the paediatricians to speak out on broader social issues that impact children's health, such as by advocating for stronger regulation around sugary drinks and fast food and liquor outlets.
"Please speak up," McGregor said. "I think you have a social licence to do so."
Consent is required by law for vaccination of children and adults in New Zealand. Young people over the age of 16 can consent to have themselves vaccinated.
In the United States this year Ethan Lindenberger, 18, gained social and mainstream media attention after outlining how he chose to get a range of vaccinations, after his own research and despite his mother's belief in vaccine conspiracies. He has spoken about his concern for his younger siblings who remain unvaccinated.
"For certain individuals and organisations that spread this misinformation, they instil fear into the public for their own gain selfishly, and do so knowing that their information is incorrect," Lindenberger said in a recent appearance before lawmakers.
"For my mother, her love, affection and care as a parent was used to push an agenda to create a false distress, and these sources which spread misinformation should be the primary concern of the American people."
In New Zealand, a Family Court judge recently ruled a 5-year-old girl should be vaccinated against Hepatitis B. Her father wanted the vaccination, and her mother opposed it.
DHB Vaccination Rates
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A Herald analysis of immunisation data from every neighbourhood in New Zealand has found just 77 per cent of 6-month-olds are now getting their vaccines on time, down 4.5 percentage points since rates peaked in 2016. Coverage of at least 90 per cent is needed for herd immunity.
Around a quarter of the total decrease can be accounted for by parents who declined vaccines, meaning the rest were going un-immunised for other reasons such as access to healthcare.
Vaccination - the facts
• Vaccines are extremely safe, with side-effects very rare and normally nothing more than a sore arm. Licensing of a vaccine needs exhaustive evaluation and testing and every batch is controlled separately.
• Vaccine-preventable diseases are serious and can cause complications including pneumonia, blindness, infection and death. This suffering can be prevented with vaccines.
Source: World Health Organisation (WHO)