Coronavirus: 'Extraordinary number' of potential vaccines, but they're still at least a year away - expert

There are "an extraordinary number of vaccines" to combat coronavirus already being evaluated, an infectious disease expert says - but he warns we're still 12 to 18 months away from seeing any of them in New Zealand.

Professor David Murdoch from the University of Otago says while it's "fantastic" that we've made such quick progress, there's "a lot of work to do" in the fight against COVID-19 before a vaccine is ready for widespread use.

Coronavirus has spread rapidly across the world since the first case late last year, infecting 330,000 people and causing the deaths of more than 14,000.

From midnight on Tuesday, New Zealand will escalate its COVID-19 alert level 4 and join other countries in lockdown, in an effort to prevent an exponential increase in cases.

Prof Murdoch says upgrading our alert level to 4 is the best approach for now, but lauds the swift action of scientists and pharmaceutical companies in developing new vaccines.

"From what we hear - and it's fantastic to hear - we've got an extraordinary number of vaccines, or at least candidates for vaccines, already out there starting their evaluation process," he told The AM Show.

"That's amazing, given that we didn't know this virus existed four months ago."

However, Prof Murdoch warns it will still take 12 to 18 months to get a vaccine in wide circulation - and that's "if things go well".

"If we've got an effective vaccine, if it's a safe one, if we've done all the clinical trials - and then ramping up production and all the regulatory issues - [12 to 18 months] is the timeframe," he said.

"So we've got to do a lot of work before then to get on top of it, but certainly the vaccine is likely to be important."

For now, self-isolation and physical-distancing is New Zealand's best tool in the fight against coronavirus, Prof Murdoch says.

"All of these measures we've been hearing ad nauseam - and we don't apologise for that - this is the time [to put them to use]. We've really only got one shot at this."