Hospitals and GP surgeries are still busy dealing with the flu: Why has the flu hit New Zealand so hard this year?

“Although the incidence is declining as we head into late August and early September, we remain vigilant,” said Dr Susan Jack, national clinical director at the New Zealand Ministry of Health’s Te Watuora branch.

While the data only shows activity in Auckland, Jack said it was a good measure of the level of illness in hospitals across the country.

Royal New Zealand College of General Practitioners medical director Dr Luke Bradford said GP clinics were still busy with flu cases.

“What’s interesting is that we’re still seeing a lot of respiratory symptoms across the country, and it’s particularly high in the South Island at the moment,” he said.

“We expect these illnesses to occur at this time of year, but this year it seems like there has been more flu than in past years.”

In mid-August, there were also six serious respiratory virus outbreaks across the country, five of which occurred in nursing homes.

The number of calls to Healthline nationwide regarding influenza-like illnesses, mainly involving infants and young children, continues to be above the 2015-19 average.

ESR virologist Dr Sue Huang said peak flu season was driven by the co-circulation of influenza A virus strains.

The two viruses are H3N2 and “swine flu” H1N1 – both of which are known to hit the elderly and children particularly hard.

“Both viruses were circulating at the same time, with their peaks just two weeks apart, which led to very high numbers of flu cases in hospitals.”

Bradford said most cases seen by GPs also had influenza A, “because it makes them feel quite unwell so they are more likely to go to the doctor”.

At the end of January, influenza A coincided with Six residents died in the outbreak Photo of Whitianga Nursing Home.

Mr Huang said doctors were finding little evidence of influenza B, which returned to New Zealand last year as H1N1 after years of absence.

“The only thing we don’t know at this point is whether we’re going to see an outbreak of influenza B before the end of the season.”

Otherwise, influenza rates are expected to continue to decline into the spring.

Based on past post-peak patterns, Bradford expects flu levels to fall over the next four weeks, “so we should see flu levels coming down by October”.

Flu isn’t the only virus keeping clinics busy, with COVID-19 and respiratory syncytial virus (RSV) also circulating widely during the winter.

As of Sunday, New Zealand’s Ministry of Health reported just over 100 cases of Covid-19 in hospitals, still about a quarter of the number of recorded cases. The last peak at the end of May.

The latest ESR surveillance shows that while there was an increase in the number of SARS cases among Auckland children in mid-August, overall levels remain low.

Jack said health authorities continue to encourage people to stay healthy and avoid going to the hospital by getting vaccinated and following other public health advice.

“Flu vaccination is an effective way to protect against all currently circulating influenza viruses,” she said. “Flu vaccination is currently free for people over 65, pregnant women and many other people.”

“Annual influenza vaccination is recommended for all children over 6 months of age.

“It’s not too late to get a flu shot.”

Before the COVID-19 pandemic, influenza was New Zealand’s deadliest infectious disease, killing about 500 New Zealanders each year.

Health experts say the coronavirus could again kill more people than the flu by 2024, although the death toll is likely to be slightly lower than the more than 1,300 reported last year.

Jamie Morton is a science and environment reporter. He joins The Herald Founded in 2011, he writes about conservation, climate change, natural disasters, and new technologies.