Having two doses of the Pfizer-BioNTech COVID-19 vaccine might soon not count as being 'fully vaccinated', says the Ministry of Health.
The vaccine, one of the first based on groundbreaking mRNA technology to be rolled out globally, has proved its efficacy over the past 12 months, with vaccinated people far less likely to be infected, hospitalised or die than the unvaccinated.
But there is evidence their effectiveness does trail off a bit six months after the second dose, leading to many countries starting rounds of 'booster' shots.
While the World Health Organization has urged rich countries to hold off while poorer countries get first and second jabs rolled out, that hasn't stopped the likes of the US, France and Israel starting booster campaigns. New Zealand, which now has one of the better vaccination rates amongst those aged 12-plus in the world, will follow suit at the end of November.
Earlier this week the UK said it would soon redefine 'fully vaccinated' as having had three shots - not two, as originally designed.
"It's very clear that getting three jabs, getting your booster, will become an important fact and it will make life easier for you in all sorts of ways," Prime Minister Boris Johnson said. "We will have to adjust our concept of what constitutes a full vaccination to take account of that, and I think that is increasingly obvious."
The current vaccine formulation was designed to fight the original strain of COVID-19. Delta has a much greater ability to infect people who've been immunised, but the vaccine is still very good at preventing serious illness. The booster shots are of the same formula - one that will work better against variants is currently in testing.
The vaccine passes the Government released this week are valid for six months from the date they were requested. Newshub asked the Ministry of Health if it had plans to change the definition of 'fully vaccinated'.
"The Ministry of Health is in the early stage of reviewing the definition of “fully vaccinated”, in light of vaccination booster doses being available from the end of this month," a spokesperson said.
Experts have long said depending on how the SARS-CoV-2 virus evolves, we could be faced with needing regular booster shots - like we do for the fast-evolving influenza virus.
But there are promising signs the third shot gives long-lasting protection that's even stronger than the first two combined. Data from Israel, which was the first nation to roll out the Pfizer vaccine, suggests it gives longer-lasting protection than the first two as well.