New Zealand officials are keeping a close eye on the Pfizer Covid-19 vaccine rollout in the UK before a vaccinations campaign is launched here.
Britain began mass vaccinating its population on Tuesday, starting with the elderly and frontline workers.
However, two people reported adverse reactions on the first day of the rollout and the local regulator is now advising those with a history of significant allergies not to get the vaccine.
During a media briefing, the government's Vaccine Strategy Taskforce chair Ian Town said Britain's deployment of the vaccine was being watched closely.
"Any reaction like that is concerning. The key thing is to monitor this over time to try and understand what the cause might have been and to ensure that when we look carefully at that data in the early part of next year we take those things into account," he said.
Town said reactions from a vaccine were rare.
Director-General of Health Dr Ashley Bloomfield noted New Zealand was in a more favourable position than other countries.
"We've got the advantage of not having to use the vaccine right now because we have no big outbreak, so we can watch and see what happens with the deployment of this Pfizer vaccine in realtime in the UK and look at the safety monitoring data," he said.
Bloomfield assured a vaccine would not be deployed in New Zealand unless officials were confident it was safe and effective.
"It is one of the reasons that on the advice of the taskforce, MBIE has bought more than one vaccine for New Zealand, partly that is to address the potential risk that one of them may not come through to production," he said.
He did not rule out the country deploying multiple vaccines.
"There will be subsequent decisions to be made about the use of a vaccine dependent on the assessment that is made by Medsafe and also making sure we have the vaccines that are most appropriate for different population groups.
"It may well be that we deploy more than one vaccine here in New Zealand, that is not uncommon," he said.
On those who are vaccinated overseas, Town said the jury was still out on whether they would be able to skip managed isolation when entering the country.
"What we need to know is the effect of the vaccine in the medium to long term and how long those effects will last.
"Now the phase three studies that are underway at the moment are examining that very carefully, so as we think about border management in the middle and second half of next year, those are things we will need to review," he said.
Bloomfield said border controls and the current elimination strategy would continue to serve New Zealanders going into 2021.
The government is expected to provide more details of what a vaccine rollout could look like here by the end of the year.