The 4-month-old is critically ill with a severe case of pulmonary valve stenosis, a heart valve disorder. The boy's mother says she wants her son's operation to take place without delay, but she has demanded that "safe blood" be used, with her lawyer saying that the family was concerned about blood containing traces of vaccines using new mRNA technology.

The New Zealand health service has denied the family's request to use blood from unvaccinated volunteers and says that the vaccines pose no risk to donor supplies. On Tuesday, the High Court in Auckland will decide whether to grant the health service, Te Whatu Ora, temporary guardianship of the baby so it can remove the child from the family and perform the surgery.

Paul White, the agency's lawyer, described the baby as "getting sicker with every heartbeat."

The high-profile legal dispute has gripped public attention and exposed the depths of Covid vaccine skepticism in some communities in New Zealand, a country that, for a time, led the world in suppressing the coronavirus.

The case, and the family's flawed scientific arguments, highlight the continuing dangers of online misinformation and conspiracist narratives, experts say. The dispute has "become a cause célèbre in the most toxic way," prompting a spike in hate speech on fringe platforms where conspiracy theories run rife, said Sanjana Hattotuwa, a researcher at the Disinformation Project, a New Zealand monitoring group,