The Australian Flunami rolls on

Flu. What the heck are you doing? Since November 2018 – traditionally a time of influenza decline as the winter season wanes to a baseline level – you’ve been causing above-any-average numbers of illnesses. And you’re still doing it. Why is it that the Flunami rolls on??

This made-up word doesn’t innately imply a more clinically severe (more deaths and intensive care admissions) flu season. The definition Im using is that there has been an earlier and larger tide of confirmed cases identified in 2018/19 than in this same time period for over two decades (1995).

Vote early, close your eyes and hold your breath

It’s voting time in Australia today. Millions of people across the nation will be sharing each other’s space in queues – some long and lengthy. They’ll be sharing each other’s surfaces too – handrails, handed over “how to vote” cards and ballot papers, pencils and cardboard voting booths.

This all raises the question of how well does paper, wood and cardboard pass along viral contaminants? Not as well as steel, marble, Formica and other hard non-porous surfaces thankfully. But if that vollie just wiped his nose then grabbed that page to hand you – maybe think twice before taking it!

Voting time is a kind of mass gathering; albeit a rolling one. Guess what else there’s a heap of today? Influenza viruses. Australia has been neckdeep in flu cases since the unprecedented unseasonal uptick that started around November last year.

Instead of that small flu season fading away so we could enjoy the festive season, it did the opposite. Flu cases ticked up and have stayed up, peaking – so far – in April at numbers 5.7 times higher than the highest April on record. I’ve talked a bit about why it’s probably not increased travel or more testing. Flu does circulate all year and it also manages quite happily in the tropics, so it’s probably more unexpected that this hasn’t happened more often, than that it finally has.

What records are these you speak of?

I speak of laboratory-confirmed influenza records. That’s the only true indicator of what’s happening. Why? Because you can have an influenza-like illness (ILI) but not be infected by the flu virus. You can have a common cold and be infected by the flu virus. Because viruses, just like their human hosts, cause things that can be placed across a spectrum of outcomes. That’s biology folks.

Most, if not all, virus infections in humans can result in a range of outcomes to our health. They cause disease across s spectrum and that spectrum is defined by whether we have any, how much and what kind of immunity, our health, our age, how much virus we got exposed to and through what portal, any genetic issues that may prevent us from mounting an appropriate immune response and the nature of the virus.

I had a look at the latest national notifiable disease surveillance system (NNDSS- someone really wanted our initials to spell out “NNDSS”) data for flu this morning. Influenza is a notifiable disease in Australia. It has been since 2001.

We’ve added 874 new lab-confirmed cases since I completed Australia’s largest flu thread on Twitter just yesterday 😉.

May has now recorded 2.2 times more flu cases than any previous May on record.

We’re past halfway in May, and new Flu cases are being added at a rapid rate. Whether this will continue into the traditional Flu season months of July-September, or this is it happening now but shifted forward a few months, is unclear and only time will tell.
Source: NNDSS. Tabulated by myself.

Flu as a notifiable disease

Flu being “notifiable” means it must be a confirmed case to make the NNDSS list. This differs from other surveillance that relies on symptoms. Flutracking.net, for example, is some great citizen science that mostly records ILIs.

But ILIs can be caused by a lot of other very different viruses (see below), so lab confirmation is essential to ensure a case is due to the flu virus – if that’s what you want to know about.

Some of those viruses are active at the same time as flu viruses as you can see in the testing result below.

Respiratory virus testing results by a private pathology lab, from all Australian jurisdictions.  The data comprises results of direct detection of respiratory viruses using PCR and does not include serological results.
Data source: Sullivan Nicolaides Pathology

Another way testing numbers may further underestimate the season’s size can be when testing isn’t requested. This could occur when primary carers decide it’s most likely flu causing your ILI and not send away a sample to test. They can make this estimate because the lab testing done so far has told them what’s circulating. Not testing saves some dollars.

Flu testing: all about trends, not absolutes

Another facet to all of this testing talk is that we don’t all get tested. Any estimate of flu activity – or of any respiratory virus’s activity based on lab testing results – is almost guaranteed to be an underestimate. Sometimes that could be a huge underestimate.

From a public health perspective though, the main point is to ensure that we all know what’s going around and what’s causing beds in hospitals to fill up and patients to die. And perhaps what is causing any underlying patterns to those disease cases, clusters, outbreaks, epidemics and deaths. Oh, and that it can still be treated by what drugs we have, or is still prevented by the vaccines we offer. For most viruses, we have few of either. For flu, we have both and that’s a reason why flu gets a lot of attention…because we can do something about it.

Deaths are under and over estimated-I dunno!

Because flu can kill indirectly, we are very likely to underestimate deaths due to flu infection. That’s largely why we tend to see big round numbers bandied about in the media. They are the nearest guesses.

There have officially been 63 flu deaths listed to date for 2019. But not every confirmed flu case gets followed up to see whether they died. And whether a death is tested for flu is up to those who manage that death.

Given that the damage and the stress of flu infections can trigger heart attacks, brain inflammation and stroke – among other things – and in addition to the direct viral effects, you can see how we might miss a lot of deaths.

What to do to keep yourself safe?

So, while the Flunami will inevitably keep spreading and occasionally killing, remember your options at this juncture:

  • Move to a desert island, population 1 (should have been there months ago – if you go with others you’ll have to wait a few weeks to make sure you are all purged of whatever viral baggage you brought with you)
  • Get vaccinated – that will likely protect you from a serious illness
  • Wash your hands often and well after you go out to mingle with the infected masses, touching all those festy shared surfaces
  • Avoid crowds (hah!)
  • Stay at home when sick so as not to infect your officemates, classmates or very young or old relatives. Don’t visit a hospital or aged care facility to see a patient or resident if you are sick! Just don’t.
  • Sneeze into your elbow and throw tissues into a bin (wash your hands again)

And that’s about it. 2019. It’s all #Flunami all the time. It’s not been a severe risign tide of flu cases, but they gave occurred early and in very large numbers.

It remains to be seen how much of this is due to more testing, and how much due to it being a truly big flu season. This will take research and publication to answer. So get onto it researchers!

References

  • The term “flunami” has been shamelessly rushed into use for this blog following its creation by Amy Coopes. All riches from the use of this term should be directed to her.

Thread on the impending flunami 👇 https://t.co/IrOGNyjQ93— Amy Coopes (@coopesdetat) May 17, 2019

The origin of Flunami (asfarasIamconcernedandIwilllooknofurther)

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