Yep. It’s a time of year in many parts of the world when viruses that love a warm human airway, kick it up a notch – influenza, respiratory syncytial virus (RSV), human metapneumovirus (HMPV), and to a lesser extent, adenoviruses and human rhinoviruses (HRVs) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). So when I hear “I’ve got a cough/headache, COVID-19 must be around” or “repeat the RAT in a bit”, I get unreasonably grumpy. There are many other viruses out there that can make you feel crook.

What respiratory virus might it be?

Right now, RSV is on the rise in Australia.

On the rise? So that’s probably what I have?

It might be, but it’s not that simple.

Laboratory testing doesn’t detect every instance of infection in our community because only some sick people get tested, not all of them. And if it’s something mild or not very noticeable, most people don’t get tested. So lab data are the tip of the iceberg.

But they are still very useful. The upward, downward or steady trends tell us something that can be extrapolated to the entire community, though.

So a rising trend means more infections, which in turn means more cases of serious illness, as well as moderate, mild, and asymptomatic illness. RSV mainly affects the very young, the old, and those with relevant underlying conditions. Like all respiratory viruses, really. These stages of life are where we have either a “young” learning immune system or an older “fading” forgetful one.

I’ve written about RSV before. Since 2021, we’ve seen an explosion of testing data. That’s not some post-SARS-CoV-2 (the cause of coronavirus disease 2019; COVID-19) thing or due to a new variant; it’s just that we started telling laboratories to submit their data so it could be nationally reported, and RSV became a notifiable pathogen.

So, since then, we can see the peaks and epidemic troughs of the endemic respiratory virus.

So, is there another virus it could be?

Hell yes! A rhinovirus is your likeliest bet right now and for most of the non-influenza epidemic period. Let’s look at data from the New South Wales Department of Health, which, unlike some other Australian jurisdictions, actually cares about communicating with you about what’s happening. And as the most populated jurisdiction, there are lots of infected people to report on, so it’s pretty solid data.

Yes, trends differ in some other regions – notably far off Western Australia and the much less-populated Northern Territory, but the NSW data give us the trends we (should) crave.

What we can see from the image above is that both adenoviruses and HMPV are on the rise, as well as RSV.

From the next two graphs, you can see that SARS-CoV-2 is low and steady, but influenza is, at last, also starting its seasonal epidemic rise.

So the odds are in favour of your illness being due to a rhinovirus. Sometimes a rhinovirus is combined with another virus (a dual, triple, or even quadruple infection).

Influenza will probably surpass the others in the coming weeks, and then it’s really any of the others, since they are all detected in similar proportions of samples. But that’s just based on population numbers. YOU could be one of the minority who have a parainfluenza virus 3, or maybe even a parechovirus.

At least we can say you almost definitely do not have avian influenza A/H5N1 (unless you’re on the coast of Western Australia having recently been blown north!).

What you have is best identified by laboratory testing.

Does it matter what I’ve got?

That’s a complicated question. For most of us – no. Personally, I’d love to have my own PCR cycler! If you’re not badly sick, rest up, stay away from work and others, drink enough water and watch The Burroughs.

If you’re in a group at risk of bad outcomes from respiratory virus infections, you should consider getting tested via your local GP (call ahead if you are symptomatic, though). For viruses with specific treatments, outcomes are best when drugs are given as early as possible.

All these viruses can masquerade as one another in the early stages of an infection – headache, cough, sore throat, fever, or “feeling hot”, moodiness, runny nose – so lab testing is the only way to know. There are no treatments for rhinoviruses, HMPV, adenoviruses, enteroviruses, or PIVs, but thankfully, they usually don’t cause very severe outcomes. But that changes with your risk. And sometimes with bad luck and viral dose.

Is there anything I can do during the winter season?

• You can wear a good, tight-fitting N95 or P2 mask (called a ‘respirator’) with bands that go around the back of your head.
• You can make sure you’re up to date with any vaccines you’re eligible for.
• You can stay clear of crowded indoor places.

At home, though, especially if you have kids, you will find it very, very tough to dodge infections because most of us don’t run our house like a quarantine facility, so bugs are going to spread.

Links

1. Respiratory syncytial virus (RSV) in Australia – worth not(ify)ing
   https://virologydownunder.com/respiratory-syncytial-virus-rsv-in-australia-worth-notifying/
2. During the first 4 weeks of life “common cold” viruses occur frequently and can make your little one sick….
   https://virologydownunder.com/during-the-first-4-weeks-of-life-common-cold-viruses-occur-frequently-and-can-make-your-little-one-sick/
3. NSW Health’s respiratory surveillance summary
   https://www.health.nsw.gov.au/Infectious/covid-19/Pages/reports.aspx