Scientists have criticised a National Party tweet that erroneously claimed "excess vaccine stock are not boosters".
Yet despite dozens of people on social media pointing out the mistake - including one of the country's top vaccination experts - the party is yet to remove or correct it.
National was responding to another Twitter user who accused the party of posting a "FALSE meme… adding to people's fears & anxiety yesterday claiming the govt hasn't ordered enough vaccines for the booster for all NZ".
"The Government has not ordered any booster vaccines," National tweeted back. The other user tweeted a screenshot of a tweet by RNZ which said the Government "has purchased enough of the Pfizer vaccine to give booster shots if the science recommends them".
"Excess vaccine stock are not boosters," National tweeted back. "Boosters are intended to prevent a drop off in efficacy by covering subsequent strains. The US intends to make boosters available in September."
Helen Petousis-Harris, vaccine safety and effectiveness researcher at the University of Auckland and former chair of the World Health Organization Global Advisory Committee on Vaccine Safety, said this was "not quite true".
"Boosters are given to stimulate immune memory. A reformulation targeting different variants is only one type of potential booster," she said in a tweet. "An alternative vaccine type or the same vaccine are the most common ways to boost."
Alison Campbell, honorary fellow and biological sciences lecturer at the University of Waikato said boosters were a "nudge to remind the immune system about what it's already learned".
"It's an additional dose of an existing vaccine. The pertussis booster I had a couple of years ago would be an example, as is a third dose of the existing Pfizer vaccine. Something that's been reworked to cover additional variants is not."
Newshub has contacted the National Party for a response. At the time of writing on Wednesday morning, the tweet hadn't been removed or corrected. Several Twitter users accused the party of spreading "misinformation".
New Zealand ordered 10 million doses of the Pfizer/BioNTech vaccine - while this is enough for everyone in the country to get two doses, not everyone will be eligible and some will refuse it, likely leaving enough to start giving boosters to those who were vaccinated early in the rollout. COVID-19 Reponse Minister Chris Hipkins in July said "of course we will be ordering more".
New Zealand also has more than 10 million doses of the Novavax vaccine on order, which is expected to be available later this year. There is evidence mixing and matching different types of COVID-19 vaccine can be effective at boosting immunity.
Two doses of the original Pfizer vaccine doesn't work as well against the Delta variant as it does with the original strains of COVID-19, but three doses does appear to help, according to early Israeli results.
Israel has already started giving third doses of the existing Pfizer vaccine - the same as the one being used here in New Zealand - and the US is planning to in September. Any trials begun on boosters covering variants would be far from complete, said Dr Campbell.
"Pfizer/BioNTech may have begun trials on the latter but that won't be out of the randomised controlled trial phase by September."
National's tweet came just a day after the Prime Minister's Office started advertising a new role - a senior analyst to help curb the spread of COVID-19 "disinformation".
"Sorry, but is this actually a piss take?" tweeted National MP and former leader Simon Bridges.