It’s not just virus particles in the air during flu season — there are plenty of myths, half-truths and misleading messages wafting about too.
We spoke to the experts to find out what science has to say on some common flu conundrums.
The biggest misconception
According to influenza experts, the biggest myth about the flu is that it’s not serious.
People tend to treat influenza quite lightly, according to Alan Hampson, virologist and former director of the not-for-profit Influenza Specialist Group.
“They see it in the same context as the common cold when it is really very different,” he said.
Kanta Subbarao, an immunologist at Melbourne’s Doherty Institute and chief of the World Health Organisation Collaborating Centre for Influenza, agreed.
“Flu can cause significant disease not just in the elderly, but also in children under five,” she said.
“And it’s not just during pandemics — seasonal flu in and of itself can cause very significant harm.”
Why is flu linked to cold weather?
In temperate climates, seasonal flu occurs during the cooler weather of winter and early spring.
Why it strikes during this time no-one knows, but Jodie McVernon, epidemiologist at the Doherty Institute in Melbourne, said there were three main theories.
“One is to do with absolute humidity and how well the virus persists in the environment,” she said.
“Another is that flu circulates at a similar time to lots of other respiratory infections which might make us more prone.
“The last is that we spend more time inside in close proximity to others which promotes the spread of infection.
And no, you can’t get the flu just from being out in the cold.
In the tropics, where the virus can peak twice or persist all year, it’s even more complicated.
“The humidity theory doesn’t really wash when you think about a tropical double peak,” Professor McVernon said.
“It could be things like the school term starting which is a great amplifier for infections in the populations, but it’s not entirely clear.”
A peak in the wet season could also be due to people crowding indoors, similar to what happens during a temperate winter.
Can the flu vaccine give you the flu?
No, because the flu vaccine doesn’t contain the functioning virus.
Monash University epidemiologist Allen Cheng said the vaccine trained the immune system to respond to an infection by fooling your body into thinking you’ve been invaded with the flu.
“The vaccine can elicit a reaction that feels a bit like the flu, and occasionally people can get a fever, but it’s not a real flu infection,” he said.
According to Professor Cheng, the other reason people associate getting the vaccine with getting the flu is because of other viruses circulating around the time people get vaccinated.
RSV is a different virus, but can present flu-like symptoms.
“It’s just coincidence that when we’re vaccinating people against the flu, this other virus is circulating,” Professor Cheng said.
How do you know if you really have the flu?
The classic symptoms of a fever and a cough are the obvious signs you’ve got the flu, Professor McVernon said, but it’s different for everyone.
Professor Cheng says that if you really want to know if you’ve been struck by the flu, you can always be tested by your GP.
“Your doctor can tell you if you have the flu, but there’s not a huge reason to do it because by the time you get the results back you’re usually well,” he said.
“Sometimes it is important to be sure if it’s the flu, particularly if you come into hospital.”
Why do healthy young adults sometimes suffer severe flu?
You’re most at risk of a severe or fatal response to the flu if you’re over the age of 65 or have chronic health issues.
“Most young healthy people believe that flu is not a big problem for them, and I think largely they are right in believing they’re likely to have a milder illness from flu,” Professor Subbarao said.
However, sometimes healthy young adults can experience a severe flu response.
“That’s the classic pandemic signature,” Professor McVernon said.
This is probably because for a flu virus to become a pandemic, it must be a mix of strains no-one has come across before — so no-one is immune to it.
“What we saw with swine flu was that older people actually had some cross-protective immunity to the swine flu strain that re-emerged,” Professor McVernon said.
On the other hand, because young people hadn’t built up as much immune protection, more of them suffered a severe response.
“It’s what flu would be like if you’d lived in a bubble for 20 years of your life and then you got it for the first time as an adult — bad,” she said.
Can air travel increase your risk of getting the flu?
We all know that feeling of dread when you someone starts coughing on a plane — and for good reason.
Getting on a plane during flu season can increase your chances of infection, but not because of the recirculated air.
The risk of infection varies depending on where your seat on a plane is in relation to an infected person.
“Research shows that if you’re in the two seats in front or the two seats behind an infected person, that’s the zone of greatest risk,” Professor McVernon said.
How can I prevent getting and spreading the flu?
When it comes to prevention, basic hygiene messages are important, like those drilled into kids at school.
“During the swine flu pandemic my kids were coming home, telling me they were taught to sneeze into their elbows and not onto their hands, and to wash regularly their hands,” Professor McVernon said.
What about wearing a face mask?
They may be popular in Asia, but they probably don’t work that well in everyday life.
Face masks can stop people from touching their faces and from transferring the virus from a surface to their nose or mouth.
But realistically, the virus-containing particles you breathe out are so small, and the fit of a face mask so loose, that it won’t prevent the virus getting into the air.
And as for the old tissue-versus-hanky debate, Professor Cheng says a good way to stop infection spreading is to sneeze into a tissue and then get rid of it.
“I don’t have any philosophical objections to handkerchiefs, but they tend to get a bit mucky, and there’s a greater chance you’ll contaminate yourself and spread it to other people,” he said.
Can our pets catch the flu?
If birds, pigs, and horses carry the flu virus, why not our fluffy companions?
Don’t worry, our cats and dogs are quite safe — at least from human flu.
However, there is some evidence that dogs can be infected with equine influenza.
“The first reports came from Florida where racing greyhounds came down with the flu, and it turns out they were using the same track as race horses,” Professor Subbarao said.
“The virus then spread through some dog shelters in the US, because there’s a lot of susceptible dogs coming and going and being exposed to each other, but it’s not a problem for pets.”
Cats and dogs have different receptors on their cells which prevents human flu viruses from latching on. So don’t panic if your dog sneezes — just enjoy the cuteness.
Will eating garlic or drinking tea help?
Professor McVernon says that while garlic and onion can help to kill bacteria, we don’t know how they work against viruses, so there’s no harm in sticking some garlic and onions in your soup or stew.
“In general, being well hydrated and resting will help keep you healthy and strengthen your immune system,” she said.
Any claims that having chicken soup, eating raw garlic, or bingeing on lemon tea will get rid of the virus are dubious.
“There’s no evidence that I know of that they work,” Professor Cheng said.
“It’s important to differentiate between things that might actually treat the flu virus, so make the illness short and stop the virus shedding, and all of those ‘remedies’ that just treat the symptoms.
“All those things don’t actually treat the underlying disease, but if they make you feel better that’s great.”