The flu season in the UK

A mini-study employing ONS registered weekly death data

Surf the internet to find when the flu season starts and ends in the UK and you’ll come across quasi-helpful statements such as this one on metro…

And such as this one from Lloyd’s Pharmacy…

December to March it is then!

The month of December may start in week 49 or 50 and the month of March may end in week 12 or 13 so this gives us a numerical bracket with which to get the ball rolling. With the ball rolling we may derive the weekly mortality rate for respiratory causal death for the period 2010/w1 - 2019/w52 and plot this out as an error bar slide, this putting visual flesh on the verbal bones:

After some cogitation I decided to adopt a mortality rate of 2.5 respiratory deaths per 100k population as my threshold for the flu season, which in turn suggested a contiguous period stretching from week 49 to week 16. We may note the blips during week 13 and week 52, this likely being a wobble in the registration process rather than a reluctance to succumb.

With a rigid (but still somewhat artificial) definition locked into place we can now pull down weekly all cause mortality for England & Wales for the period 1970/w2 through to 2022/w13 and calculate the seasonal mean all cause mortality for all flu seasons from 1969/70 to 2021/22¹. Here’s what this little tray bake looks like…

Whilst this largely mirrors the weekly mortality presented in part 9 of my weekly deaths update series there are a couple of interesting features worthy of a munch. Firstly, we may note the 1975/76 season was rather harsh and some general practitioners may well remember this. 1989/90 would also have stood out after three particularly quiet seasons.

Secondly, we may note the upturn after the 2011/12 season that coincides with the introduction of the Health and Social Care Act (2012). This piece of legislation brought in the most wide-ranging reform of the NHS since its inception in 1948, this being a reform that is evidently destroying the health of the nation in the pursuit of efficiency and profit.

One interesting feature of this slide is the increased scatter from the 2011/12 season onward with seasons oscillating wildly between ‘good’ and ‘bad’. Another interesting feature is that the pandemic doesn’t stand out as we may expect: there is a high point for 2020/21 but this seems to continue an upward trend of a run of ‘bad’ seasons. If you didn’t know about the pandemic you certainly wouldn’t guess anything was amiss apart from the decline in healthcare provision following the 2012 Act. I shall conclude that the government is more dangerous than any virus.

1. Weeks 49 - 1 will be missing from the 1969/70 season and weeks 14 - 16 will be missing from the 2021/22 season but this isn’t going to make much of an impact.