Children who received expired Pfizer COVID-19 vaccine still protected - medical advisor

A vaccine expert says 56 children who received an expired dose of the Covid-19 vaccine are still likely to have high protection against the virus.

Taranaki District Health Board announced yesterday the expired paediatric doses were administered between 28 March and 6 April.

"The administering of an expired vaccine happened following a misinterpretation of the Ministry of Health's extended expiry date on some paediatric vaccines on March 9, which extended the Pfizer Paediatric expiry dates from six to nine months. The extension related to frozen stock, not refrigerated stock, which remained at 10 weeks," the DHB said in a statement.

All affected whānau were being offered a free appointment with their GP or medical provider to seek further advice and make an individualised plan for the next steps for their child.

Immunisation Advisory Centre medical advisor Peter McIntyre said the doses were thought to still be highly effective because they had been expired between one and 11 days.

"With the adult vaccine, there has been some more work on that and it's been decided that up to two weeks [after the expiry date] is OK. It's just that the paediatric vaccine has a slightly different preservative and there isn't exact data on it," he said.

"I think the chances are very, very strong that there would still be a good immune response and they'll still be protected even though it might be a little bit lower."

McIntyre believed it was good news for parents and it was now up to families to decide whether they believed their child needed an additional dose or not.

Every child's circumstances were different, though an extra dose would most likely be beneficial for those with an underlying health condition, he said.

"If I had a child who was at particularly high risk of having troubles with Covid, let's say they had severe heart or lung problems, then I would probably err on the side of caution by saying it would be best to have the additional dose just in case."

Another factor for whānau to weigh up is an increased risk of side effects from an additional dose, he said.

"If you give an extra dose, there will be an increased chance of side effects."

"Side effects aren't a big problem, but on balance, I would say that the risk of greater side effects is more of an issue for an otherwise well child, than the small chance that the vaccine may not work as well as we'd like it to," he added.

Taranaki DHB also said it has received clinical advice on the issue and the 36 children who received a dose within 48 hours of its expiry, do not need an additional vaccine.

RNZ