COVID cases will likely drop during school holidays before next wave hits during winter - modellers

Easter weekend and the school holidays are well underway and after nearly two years of no travel, airports were abuzz over the weekend.

But instead of causing a surge in COVID cases, the holidays could help bring case numbers down.

Auckland University COVID modeller Dion O'Neale says closing schools has helped to keep the numbers down and the holidays could see a further drop in case numbers.

"Because you've closed schools - you get lots of spread of respiratory disease in schools and kids bring that home to their families, so we'd expect that to have just stopped and we'd actually expect over the next couple of weeks to see slightly lower case numbers," said Dr O'Neale.

The borders have reopened along with two long weekends in a row and the school holidays. It will be a busy time for New Zealand with 93,000 passengers expected to have gone through Auckland Airport this Easter weekend.

Epidemiologist Michael Baker says it's great that people are getting out and about, but it's essential they take precautions.

"We're still seeing this long tail of people dying from this infection, seven-day rolling average of 14 a day, and that's going to add up unfortunately to a lot of deaths in the next month or two," said Prof Baker.

"We can prevent some of those deaths occurring now."

Official figures say 800,000 New Zealanders have had the Omicron variant of COVID-19, but modellers say it could be as many as two million or more.

"The true number of infections is probably going to be maybe two or three times that. We'd expect at the end of this first wave that about half of the population would be infected," said Dr O'Neale.

He said without a prevalence survey, they're forced to make assumptions.

"That's a little bit concerning because if we don't know how many infections there have been then we don't know how to model for reinfections and the waning immunity coming from those infections, so it makes it really hard to do modelling for a second wave and subsequent waves," said Dr O'Neale.

The next wave of cases is expected to hit during winter and Prof Baker says we need to get vaccinations up to date before the wave hits.

"Only a bit over 20 percent of school age children are fully vaccinated, and a third of adults who are eligible for boosters haven't received them yet," he said.