The return of flu season, which went missing for a couple of locked-down years, was predicted to hit hard – and it did, kids especially.

And while the number of influenza notifications continues to sit above the five-year average, cases peaked in early June and have since dropped away at a fast rate.

The first peak did, anyway.

Infectious disease experts caution against celebrating flu season being on the way out before spring – because there could be a second peak. But you wouldn’t put money on it.

Professor Robert Booy, from the University of Sydney, told Australian Doctor, a subscriber-only news and clinical advice publication for health workers: “There is a small possible – but not probable – risk of a further surge of influenza B, but so far, it’s not there.”

The numbers tell the story

Within a couple of weeks – from the second half of June to the first half of July – the number of influenza notifications dropped by more than half (down 55 per cent).

The federal Department of Health and Ageing’s seventh influenza surveillance report for the year, covering the fortnight ending on July 3, recorded 37,000 cases.

The eighth surveillance report, covering the fortnight up to and including July 17, recorded 16,7000 cases. .

In total, there have been 204,911 notifications for the year up to July 17  – and there have been 118 influenza-associated deaths reported to the National Notifiable Diseases Surveillance System.

The highest notifications have been for children under the age 10, followed by those aged 10-19.

Professor Booy told Australian Doctor that the pool of influenza-susceptible young children with no prior exposure to the flu was now “running out”.

He said the “chains of transmission are getting shorter and blocked because children are now either immune from infection or vaccination”.

Older people kept wearing masks

It was assumed that older people would be routine victims of the season but Dr Booy said elderly patients were “playing hide and seek” with the virus.

He said that although it’s not mandatory to wear masks and observe social distancing, a lot of older people “still take a lot of precautions”.

He said: “Normally, they would have fed into the surge in flu over winter, [but] they’ve done less of that and stayed at home, socialised less, worn masks and continued to observe social distancing.”

Australian Doctor advised that other potential explanations for the drop in influenza notifications could be high rates of both COVID-19 and respiratory syncytial virus in the community.