The Immunisaton Advisory Centre is reassuring people there are no safety concerns with blood from donors who have been vaccinated against Covid-19.
It comes as the parents of a four-month-old baby are refusing to treat their child's severe heart disease because they don't want to use blood from people who have had the Covid-19 vaccine.
Immunisation Advisory Centre medical director and vaccinologist Nikki Turner told Checkpoint blood from a person vaccinated against Covid-19 was not contaminated in anyway.
Rather, it contains the body's immune response to the protein that is on the virus, which is similar to what a person infected with Covid-19 would have in their blood too, Dr Turner said.
"That's the same [for] any virus we're exposed to, Covid or any other virus. So from a science point of view, there are no concerns here.
"The code that you injected into the person that receives the vaccine is removed very quickly within a few days. So that's not there, it's the immune response that the body reacts to."
Listen to the full interview with vaccinologist Nikki Turner here
There was also no scientific evidence to suggest the blood of people vaccinated against Covid-19 posed a risk to children, she said.
"There's no science reason why there would be [a risk]. If you work through the explanation of how vaccines work, there's no scientific reason why there would be a risk."
Blood donations were carefully screened for safety and to ensure it was a match to the recipient, she said.
"We've got to watch out that there's no viruses you know, for example, HIV or Hepatitis virus.
"New Zealand has a safety process that we have set up and developed over years."
For people who may still have concerns about the safety of donated blood from people who have had the vaccine, Dr Turner advised them to talk to someone they trusted who was a professional in the field.
"The scientific community in general has been watching incredibly closely for the safety of these mRNA vaccines.
"I think people need to talk to someone they feel they can trust to talk through these issues ... talk to a health person with knowledge and with understanding, that can genuinely work through your concerns.
"There's a lot of myths and scary stuff out there for people and oh my goodness, I get it, and we can really easily go down these rabbit holes, but I think it requires [people] to work through [the science and concerns] step by step and to re-establish a bit of trust."
The legal aspects of the case
Te Whatu Ora is making an application under the Care of Children Act regarding the baby who is at the centre of the debate and needs open heart surgery.
It is asking that the baby be placed under the guardianship of the court.
Te Whatu Ora then wants the court to appoint the doctors as agents of the court for medical care, and the parents agents of the court for all other care.
Both the agency and the parents say the matter is urgent and are attempting to organise mediation before a hearing next week.
Liberty Law medical lawyer Rebecca Keenan, who is also a former nurse, told Checkpoint health officials could intervene if the condition of the baby deteriorates.
"The courts would much rather that the medical team and the child's parents come to an agreement over how they can move forward," Keenan said.
"But obviously the doctors are saying that in this case, for this young child ... his life is hanging by a thread and that we don't have the time anymore to try and get to an equal situation where we both agree on what can happen," she said.
"And in those situations the courts will generally preside on the side of the doctors because our law says that the best interests of the child is paramount."
Listen to the full interview with Liberty Law medical lawyer Rebecca Keenan
The period that the order would be in place for, if the court does side with the doctors, would be guided by what the health board had submitted in its application, Keenan said.
"Really it's guided by the doctors' specialist knowledge as to where it starts and finishes, but I would say it seems to be a question over that they don't want them to have blood by people who have potentially had the Covid vaccination, so that's fairly limited, so it may just be for the surgery itself and the post-operative immediate care."
The courts would still weigh up the parents' position, regardless of whether it was proven fact or not, similarly to considerations for religious beliefs, she said.
"A lot of people would say that for religious beliefs that there's no foundation for it, but this is the parents' firmly held belief that they are acting in the best interests of the child and the courts would just weigh that up.
"I suppose you could say that as a fact that would make the health board's case stronger because they would be saying to the judge, 'well, we're saying that though they have this fear, which is a legitimate fear for them, the science doesn't back up that fear and because of that we're saying the risks involved are so minor that you should be deciding the best interests of this child to have the blood that we're saying is safe for this child'."