Professor Peter Collignon

I think we need to be more honest about it because if we oversell these vaccines and how much they'll protect you, we run the risk that people won't get the vaccines that we absolutely should be promoting for 100% of people.

Well, the main way flu spreads or any respiratory virus is we breathe it in or we take it in through our nose or through our mouth that gets into our respiratory tract, but also it can come in through the eyes.

Because your eyes are connected to your nose, if people cough or splutter, some of that can get into your eyes.

and goes down to your nose where it then multiplies.

And also your hands can be a factor because people, when they cough and splutter, touch surfaces.

And if you then touch that surface and touch your eyes or touch your nose, well, that's another way of getting the virus where it needs to get, which is inside your respiratory tract.

Well, the short answer is you can't with any accuracy.

I mean, in general, what we're taught at medical school, and probably is true, is influenza makes you sicker than the common cold virus.

But there's so much overlap.

If you're sick, you can't really tell.

I remember many years ago, I was really sick, even before PCR tests, which we do now, when I worked at Westmead.

And I got a test done because I was just so terrible and ended up being a rhinovirus, the common cold virus, even though I felt I was the worst I'd been in my life.

Flu or influenza is particularly bad in winter and we for four to six weeks have a lot of people who come into hospital because they're so sick, mainly people with underlying disease or older.

But if you look at some data from the US, the common cold virus, rhinovirus, puts more people into hospital than influenza.

The difference is it's spread over the whole year rather than a short peak in winter.

So the short answer is you can't tell yourself.

You can do a test.

Now we have PCR tests and it can tell you up to 12 different viruses that you might have.

But for most people, it doesn't really make a lot of difference in how you manage.

There are some anti-flu drugs, but if you've already got immunity and reasonably well, instead of being sick for six days, you're sick for five and a half.