Are we in for another Covid summer?

As case numbers steadily tick up from the relatively steady plateau of the last few months, is New Zealand in for a Covid summer?

This summer, New Zealand's in a markedly different place to what it was a year ago when it comes to Covid-19. 

Last December, Auckland was just coming out of lockdown, with widespread health measures still in place. 

"Two shots for summer" was the government's slogan du jour as it tried to drive up vaccination rates.

The hope was that summer would act as a circuit-breaker, stopping the nascent Delta variant in its tracks. A season of outdoor recreation in the ventilating breeze was a well-timed chance to gain a foothold in New Zealand's long and slow battle with the virus.

But this year, as we come into summer, case numbers are ticking up again after a relatively stable plateau. 

This time around, a complex mix of subvariants and the abandonment of most health restrictions seem to have left Ministry of Health deputy-director Dr Andrew Old somewhat uncertain as to how the summer months will play out.

"As much as we all wish it were the case, we are not out of the Covid woods yet," he said.

Newsroom's Marc Daalder has been following the government's response to the pandemic closely since the beginning. 

He says there's no reason to think we'll be getting out of the woods anytime soon.

"Everything we know about Covid so far and viruses in general tells us that yes it will continue to mutate and evolve, but there's no particular reason that it would evolve to become less severe than it currently is," he says. 

"It may, but it's not guaranteed to."

And with relatively high uptake of a vaccine that is effective at reducing severity, but not so effective at stopping spread, the stage is set for another wave.

It could be considered good timing, however, as more outdoor recreation and less winter flu do their part to cut down on spread and reduce the chance of a health system overload - crucial at a moment when the sector is still crying out for solutions to its widespread staffing shortages.

However, the Kiwi tradition of moving about the country over the Christmas period could also mean spread between provinces kicks into another gear.

Meanwhile, a varied mix of different versions of the virus hitting the population at the same time adds another layer of complexity.

University of Auckland computational biologist David Welch said while reduced restrictions likely played a bigger role in the cresting wave, new variants that have been recorded in New Zealand have had impacts around the world.

"In the background, we've started to see more and more new variants arriving, and those have been having an impact around the world," he says. 

"They're starting to reach quite significant levels in New Zealand, and maybe causing another uptick in cases."

While in the past, one new variant with a clear advantage has arrived and established itself as the main form of Covid-19 going around, the variant soup is made of a much more gradually changing set of viruses, slowly changing via antigenic drift - the gradual accumulation of small changes to a virus that transform it over time.

Rather than a step-by-step voyage through the Greek alphabet, it seems the new changing face of Covid is a more complex array of letters arranged to signal a slow and incremental change to the original virus.

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