By Liu Chen of RNZ
Health experts are urging New Zealanders to take advantage of the Covid-19 vaccination rollout, but reminding them that it takes a while for the vaccine to take effect.
An Air New Zealand crew member tested positive for Covid-19 days after receiving the vaccine, and the Ministry of Health says the person cannot have caught the virus from the vaccine - as it does not contain any live, dead or deactivated virus.
The first tranche of the vaccine rollout is underway, with thousands of front-line workers having received their first jab, but vaccinologist Helen Petousis-Harris said it did not offer instant protection.
"It does take time ... you're actually not going to see full protection until at least a week after your second dose," she said.
The second dose is given three weeks after the first dose, so it takes about a month for a person to have at least a 90 per cent protection, Petousis-Harris said.
"It's not an instant magic bullet and also when you've got lots of virus out there, there's also the chance that it will still slip through, but I think we're going to see this making a big difference, so most people who get the vaccine will be protected."
The crew member flew in from Japan on February 28 and tested negative for Covid-19. They received their first vaccine on March 3. Four days later they returned a positive Covid-19 result.
The Ministry of Health said the most likely scenario was that this person was exposed overseas and was either incubating or infectious with Covid-19 before being vaccinated. It said everyone who was at the vaccination site at the same time was being tested and isolated.
The Malaghan Institute's Vaccine Alliance Aotearoa clinical director, Dr Fran Priddy, said there was no evidence the vaccine affected people who had already contracted the virus, but if people did catch the virus after getting jabbed, their symptoms might be less severe.
"It does look like they tended to have less symptomatic disease, but still not a lot of information yet on that. That's just early data."
New Zealand's first Covid-19 vaccine is manufactured by Pfizer/BioNTech and Priddy said there was good safety data and strong scrutiny of the vaccine.
"New Zealanders should definitely take advantage of these products ... they're going to be the answer to winding down the epidemic worldwide and opening borders and getting back to some level of normalcy."
Microbiologist Dr Siouxsie Wiles said there were uncertainties around how effective the vaccines were against different variants and the number of doses required.
"I guess what's happening around the world is there are countries that have got high amounts of the new variants circulating who are also doing a lot of vaccination, and so hopefully we'll find out from those countries just how effective the new vaccines are."
She said while the vaccination was being rolled out, people should still keep up good hygiene practices, including mask-wearing.
Massey University research showed 36 per cent of New Zealanders were vaccine enthusiasts, 28 per cent were supporters, 24 per cent were hesitant and 12 per cent were sceptics.