MEASURES designed to stop the spread of the coronavirus in Australia seem to also be suppressing flu in the country.
Australia's flu season normally peaks during its winter months, from June to August. But cases often start to build around January, as travellers from the northern hemisphere bring the virus into the country.
This year, Australia had 6962 laboratory-confirmed cases of flu in January and 7161 in February. However, detected cases have since nosedived, with 5884 recorded in March and only 229 in April, compared with 18,705 in April 2019. This is despite more flu testing being conducted this year.
Australia's FluTracking surveillance system, which surveys about 70,000 people each week and records their flu-like symptoms, shows that in the week ending 26 April, only 0.2 per cent of Australians had symptoms. This figure was 1.4 per cent at the same time last year.
The sharp fall in cases is probably due to Australia's decision to control the spread of covid-19 by banning non-essential gatherings of more than 500 people from 16 March and then to shut its borders on 20 March, says Robert Booy at the University of Sydney. “We're not importing any flu and anything that stops close contact with others is going to make it harder for the influenza virus to transmit,” he says.
On 23 March, non-essential businesses such as pubs, gyms, restaurants and cinemas were forced to close.
Additionally, in mid-March, states and territories began encouraging remote learning where possible. This is probably another reason why flu cases are down, says Kirsty Short at the University of Queensland.
These measures also meant Australia reported 20 or fewer new covid-19 cases each day in the week up to 1 May. If the measures are kept in place, flu cases should continue to be suppressed too, says Booy. “That could mean we see fewer deaths from respiratory infections overall this year,” he says. Covid-19 deaths in Australia have been relatively low at 95 up to 4 May. Between 1500 and 3000 Australians die of flu in a normal year.
But even if the restrictions are eased, we could still see a reduction in flu cases due to behavioural changes, says Short. “People are washing their hands more and instead of having the attitude that they can still go to work if they're sick, they now know to stay home if they have respiratory symptoms,” she says.
More people than usual have been vaccinated against flu this year, which may bring cases down as well, says Short. But they may rise again when students return to school, she says. Some studies suggest school-aged children transmit the coronavirus less. “But we know that children are a hotbed of influenza infection,” says Short. “It will be interesting to see what happens.”