COVID-19: Delta variant to create 'rough trip' in coming months, may mutate to become more vaccine-resistant - expert

Epidemiologist Michael Baker warns we're in for a "rough trip" with the Delta variant of COVID-19, with the virus having "many opportunities" to change in the coming months. 

It could even mutate into a version that is more resistant to the current vaccines.

While New South Wales clocked up 919 new cases of COVID-19 on Wednesday and Australia talks up "living with the virus", New Zealand is stick with plan A - trying to eliminate it.

"It's too soon to throw in the towel," COVID-19 Response Minister Chris Hipkins said.

Prof Baker agrees.

"We should absolutely reject any idea we should let the virus wash over us without a very good fight," he told Newshub.

He pointed to China - which has crushed 30 outbreaks of Delta and returned to zero cases.

Prof Baker said in the long term, New Zealand could change its strategy and live with the infection - but not before the health system, vaccine rates and border controls are improved. 

"We may be able to tolerate endemic infection but I think we should be postponing that for as long as we can."

Dealing with Delta is complex. Academics have warned of COVID-19's ability to change into a more infectious dangerous version. 

The idea behind what's called "antigen shift" is the Delta variant could pick up RNA or genetic material from a currently circulating endemic virus, like the common cold.

In a report to the UK government, the Scientific Advisory Group for Emergencies academics stated: "The consequence could be a virus that causes disease at a level similar to COVID-19 when it first emerged but against which our current battery of spike glycoprotein-based vaccines would not work."

The report noted the likelihood of this as being a "realistic possibility" 

"One of the concerns is we could suddenly see the virus or a new variant with a high degree of resistance to our vaccines," Prof Baker said.

"I'm not a prophet of doom - I think humanity can conquer this virus but it's going to be a rough trip as we're seeing."

Prof Baker said it could be years before the virus hits what he calls "maximum fitness" when it's evolved as much as possible. 

However, he emphasised the prospect of antigen shift is not a reason not to be vaccinated. He said the vaccine remains the best tool we have - it's just that its effectiveness could decrease over time.