Moderna said on Monday it believed its vaccine protected against a highly contagious strain from South Africa as well as a variant that has wreaked havoc across the UK.

But it said it would test whether a third “booster” shot would prove beneficial against the South African strain or future mutations.

Moderna CEO Stéphane Bancel said the company would continue to be proactive as the virus rapidly developed.

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“We are encouraged by these new data, which reinforce our confidence that the Moderna COVID-19 vaccine should be protective against these newly detected variants,” he said.

The Therapeutic Goods Administration (TGA) granted provisional approval for the Pfizer vaccine on Monday, and the federal government has also struck deals with AstraZeneca and Novavax.

But it has yet to agree a deal for the Moderna vaccine, which Health Department secretary Brendan Murphy described as “very similar” to the Pfizer jab.

Early signs suggested the Pfizer vaccine was effective against the UK strain, but other research raised questions over its effectiveness against the South African mutation.

Professor Murphy would not be drawn on negotiations with Moderna on Monday.

“We are continuing to evaluate and in discussions with all of the major companies. Those discussions are commercial in confidence. We are continuing discussions with all major vaccine companies,” he told reporters.

NCA NewsWire has reached out to Health Minister Greg Hunt for comment.

It comes as New Zealand Prime Minister Jacinda Ardern expressed her “disappointment” over Australia’s decision to suspend quarantine-free travel for New Zealanders for 72 hours after the strain jumped the country’s hotel quarantine system.

“I conveyed the confidence that we have in our systems,” she told reporters on Thursday.

“If we are to enter into a trans-Tasman bubble, we will need to be able to give people confidence that we won’t see closures at the borders that happen with very short notice over incidents that we believe can be very well managed domestically.”

But Ms Ardern would not be drawn on whether the decision was an over-reaction, saying it is ultimately a matter for Australia.

She confirmed New Zealand was continuing to pursue a trans-Tasman bubble but conceded a country-to-country arrangement looked “increasingly difficult”.

New Zealand authorities were scrambling to trace the contacts of a woman who tested positive after being released from quarantine in Auckland.

The 56-year old was the country’s first case of community transmission in over two months and was believed to have visited around 30 venues while carrying the virus.

New Zealand confirmed no new community transmission cases on Tuesday.

But with 13 people having tested positive to the strain in Australian hotel quarantine, acting chief medical officer Michael Kidd defended the temporary measure.

“They have then been out in the community for the past 10 days, visiting a number of venues interacting with other people in the community,” he told the ABC on Tuesday.

“(Suspending quarantine-free arrival) allows time for the New Zealand authorities to follow up with all the contacts of this individual to see if there has been more widespread community transmission of this particular variant.

“Then we can see if it’s safe to resume the green zone arrangements or not.”