Experts are assuring New Zealanders COVID-19 vaccines bought for the country will not be a health risk despite concerns the speed of vaccine development could compromise on safety.
Scientists around the world have rushed to find a vaccination since COVID-19 emerged less than a year ago.
Now as the worldwide death toll nears 1.5 million, trial results of various potential vaccines have been rolling in and showing promise.
Final results from Pfizer Inc's vaccine trial showed its shot had a 95 percent success rate and Moderna Inc's experimental vaccine is 94.5 percent effective in preventing COVID-19.
The results of the vaccines have so far exceeded expectations, but many people have expressed doubt about the safety of the jabs.
Professor Jamie Triccas, head of infectious diseases and immunology at the University of Sydney, is insisting the vaccines will be safe.
He's backed by Dr Nikki Turner, an associate professor in Auckland University's Department of General Practice and Primary Health Care and director of The Immunisation Advisory Centre.
The researchers said there are a variety of factors which have led to the vaccines being developed so fast and assure that it isn't compromising safety.
"'Fast-tracked' is not the right word because the science has not been fast-tracked," Turner told Newshub on Thursday.
"It's not that anyone is jumping and shortcutting safety mechanisms, well they aren't in New Zealand. The reasons why it's actually happened faster than anyone expected is because firstly, vaccine science has come a long way, in the last 15- 20 years the knowledge around vaccine science has just expanded exponentially."
Dr Turner said back when the virus emerged in January, China gave samples of the virus to scientists around the world so they could develop a vaccine early, and they already had an understanding of the coronavirus family of viruses, which gave them a "headstart".
The huge investment in finding a solution to the pandemic had also helped to speed up the process, the researchers said.
Normally scientists take years to secure funding and grants to develop and test vaccines, but due to the global and devastating impact of the pandemic, billions of dollars were quickly put towards it.
"In terms of the development of vaccines, there haven't been any shortcuts," Prof Triccas told news.com.au.
"The big difference between COVID and other vaccines developed in the past is that clearly, the impact has been so great and so widespread the investment has been unprecedented.
"Things have been able to be done in parallel without compromising safety that could never normally be done simply because of cost."
Dr Turner said that a lot of the COVID-19 vaccine development was also able to be completed parallel, rather than sequentially due to the priority placed on it.
"Stuff that normally takes years - you normally do the animal studies, you normally do the phase one, phase two, phase three [trials] and then you go for licensure - they all normally happen in a sequence after each other," she told Newshub.
"Well, what they've managed to do is run some of those in parallel, so that while you are doing animal studies and the phase one and two, you are already planning phase three. So as soon as you see that the vaccine may possibly be a potential vaccine you can hit the ground running with the next phase. It was planned way earlier than they've ever been planned before so that sped a lot of the vaccine processes up considerably."
Dr Turner said other "bottlenecks" which normally come with vaccination development have also seen less barriers including manufacturing.
"Once you've got a vaccine then you need the big manufacturing plants to make them and huge amounts of money goes into developing manufacturing plants," she said.
"But they took the risk and enormous amounts of money to build manufacturing plants which may not be used so that the manufacturing plants are then up and built and ready to go when the vaccines get through the studies."
Dr Turner assured that New Zealand will also have an advantage in ensuring the safety of vaccines due to our favourable position with the virus.
Currently, the country only has 60 cases of COVID-19, 55 of which were detected at the border.
"New Zealand is not going to license a vaccine until they are through phase three of the studies," she said.
"There are some countries in the world that have got really high rates of severe COVID disease and so they may get what they call interim licensure. They might run earlier based on interim results but New Zealand will not do that. We don't have huge rates of disease so we can afford to wait a few more months."
Prof Triccas told news.com.au that there was no reason not to trust the vaccine.
"There is a bit of hesitation because it's all happened so quickly – the pandemic hit us and nine months down the track we've got a vaccine, which seems pretty fast," he said.
"But what we've seen so far is that there's nothing to fear.
"The reality is that everyone will have to take it because unless we do, we'll never get it under control – it's a relentless pathogen and it just needs a very small foothold before it explodes like wildfire. You do not want to get infected by this virus and take risks."