New Zealand is moving into the warmer months with low COVID-19 case numbers - but experts are warning a wave could disrupt our relaxing Kiwi summer.
New subvariants are driving an increase in cases overseas and an expert said it is "increasingly likely" the wave could travel to New Zealand this year.
When it comes to diseases, summer months are generally less transmissible as we open our windows and let in the fresh air.
Added pressure on the health care system also eases as we see fewer seasonal respiratory viruses, like the flu, circulating.
"Heading into summer works to our advantage but at the same time it is possible to get a wave," COVID-19 modeller Michael Plank said.
Another surge in COVID-19 cases in New Zealand depends to a large extent on what happens with new variants.
Prof Plank said while it is difficult to predict variants in advance, there is a combination of strains overseas that look like they are going to be capable of triggering a wave.
COVID-19 modeller David Welch said a "constellation" of variants in Europe are starting to drive an increase in cases.
"We would expect something similar to happen here," Dr Welch said.
Dr Welch said what is happening in Europe is different from what we have seen before.
Previously there have been standout variants, such as Delta and Omicron, which have caused waves worldwide. But now there are several variants with very similar mutations that seem to be on the rise.
This week, World Health Organization (WHO) officials said hundreds of new forms of Omicron are being tracked by scientists.
WHO data found cases in the EU were up eight percent at 1.5 million to the prior week, despite a dramatic fall in testing.
Waning immunity could also be playing a role in the uptick in cases overseas as time ticks over since many people's last COVID-19 vaccine and infection.
While waning immunity and the Northern Hemisphere entering winter will be playing a role in the rise in cases overseas, the swarm of new variants, most of which are mutations of Omicron lineages, have overseas officials worried.
One thing that remains to be seen is whether these new variants have the ability to escape immunity from previous variants.
Overseas scientists have said there are signs the emerging Omicron sub-variants could be evolving to dodge immunity - adding a lot of uncertainty to what we can expect in the coming months.
"It is looking increasingly likely that we will see a variant-driven wave here in New Zealand at some point this year," Prof Plank said.
Given the risk of a surge, it is crucial for people to stay up to date on their vaccines. Dr Welch said the best way to get immunity back up is to get the booster vaccines.
He thinks the Government should look at extending eligibility for the second booster to younger age groups.
Currently, the second booster is available to everyone over the age of 50 and health, aged care and disability workers aged 30 and over.
It is also available for people over 16 that have a medical condition that increases the risk of severe breakthrough COVID-19 illness or live with a disability with significant or complex health needs or multiple comorbidities.
The Ministry of Health is expecting the next round of advice on second boosters in the coming weeks.
