Saturday, 8 August 2015

Queensland influenza sees a shift in age...

Image adapted from Geoscience Australia,
The Australian Government.[3]

The media Down Under have been doing their thing this influenza season...

...lots of inflammatory (pun intended) headlines to make us all fear just about everything and everyone. Blah.

Nonetheless, it is flu season down here - and hopefully you gave vaccination a try this year, or you got your annual shot. Top marks if so! If you can safely and pretty painlessly dodge a preventable disease, save yourself some misery, avoid making your kids sick - who will require time off to be looked after, not make Aunty Robyn crook as a dog and not put Grandad's ailing ticker under extra stress...why wouldn't you? 

VDU Figure 1. Figure 2 from the State of
Queensland (Queensland Health) report
found here.[1]
Click on image to enlarge
Thanks to the excellent and publicly available wealth of data presented by the epidemiologists of the State of Queensland (Queensland Health), I talked about influenza in Queensland and the distribution of types (i.e. Flu A or B) and subtypes (e.g. H3N2 or H1N1) last year.[2]

In 2014, influenza A viruses were the big bad, but in 2015, as we can see in VDU Figure 1 (orange), influenza B viruses are ruling the mean streets.

VDU Figure 2. Appendix 1 from the State of
Queensland (Queensland Health) report
found here.[1]
Click on image to enlarge
From the look of VDU Figure 2, the influenza season remains in full swing (hint-get that vaccination if you haven't already). 

VDU Figure 2 also shows that things are not tracking all that unusually for a Queensland influenza season when you compare this year to curves from the past 5 years. So I'd suggest taking those media headlines with a box of tissues!

However, something stood out to me when looking at the latest report so I went back and cut-and-pasted the age and sex graphs from the past few consecutive weeks to make VDU Figure 3. Sure enough, there was a particular spike in the 5-9 and 10-19 year old age bands (yellow arrows in graph boxed in red). Even allowing for changed y-axis scale in the first 4 graphs (dates are listed in each graph's legend) these 2 bands seem to have risen just in the past reporting week. 

Still, the overall pattern of rising case numbers, a dip in the 20-29 year old age band, then a rise before a consistent drop off is retained. Is this the result of school kids returning from school holidays on the 23rd of July, sharing their viruses, incubating an infection and becoming ill? If so - will we see a rise in parent - age age bands in the report after next's? Let's watch and see!

VDU Figure 3. Figure 4s from previous weeks of State of Queensland (Queensland Health) report found here.[4]
Images excised from PDFs and pasted together using 

Adobe Photoshop CC 2015.0.0
Click on image to enlarge
References....