An infectious disease specialist believes a COVID-19 vaccine is between 12 and 18 months away even if everything goes to plan.
Otago University Dean Professor David Murdoch says while that may seem a long time, some vaccines have taken up to 15 years to get to market.
He says it's "extraordinary" that clinical trials have already started.
"The fact clinical trials are starting is amazing when you think that four months ago we didn’t even know this virus existed."
Earlier this month, the World Health Organisation revealed its three leading candidates in the race to find a vaccine; the Beijing Institute of Biotechnology in partnership with Hong Kong's CanSino Biological Inc and US biotechnology companies Inovio Pharmaceuticals and Moderna.
There are 67 other vaccine candidates still in the preclinical stages of development at institutes such as Osaka University in Japan, Australia's University of Queensland, and the University of Oxford and Imperial College London.
According to Prof Murdoch, the preclinical stage seeks to determine how the vaccine is going to work and whether it's going to be harmful.
Live cells will be grown labs with possible animal studies looking at whether it will produce an immune response, he said.
He said developing a vaccine is not the end of the process.
"Each country or region will have its own challenges and work is required to determine the suitability of the vaccine for the population, along with funding and logistics considerations."
Prof Murdoch said recent events such as the West African Ebola outbreak have pushed technology, adding he hoped to see a quick process for a vaccine.
"I'm optimistic. There are a lot of clever people working on this."