Thread by @SGriffin_Lab

We often hear "live with it, just like the flu"...

My response is, and always has been, DO NOT play virus top trumps - it's daft.
As @covidinquiryuk continues, one thing I hope we can take forward, it's how to do things better, rather than how it's "normally done"... brief🧵

https://twitter.com/Rajeev_The_King/status/1669018716124618752

Influenza A virus has been the top of the list for potential pandemics since time immemorial, not JUST because of the 1918/19 pandemic and its aftermath, but because of all the other pandemics of the 20th and 21st centuries that are less familiar to many:
science.org/doi/10.1126/sc…

What followed each pandemic was the dominance of that particular virus for many years after, causing seasonal flu. Note, seasonality is complicated, it doesn't really occur in tropical regions and is not just driven by our behaviour...

annualreviews.org/doi/10.1146/an…

This pattern is what many people expect for the future of SARS2, for which we have, or at least had, an unparalleled amount and granularity of data around its evolution since crossing into humans. Strikingly tho, SARS2 changes MUCH quicker than flu does

https://twitter.com/trvrb/status/1554890581196693504?s=20

The situation with flu is, to my mind, a bit like the excess deaths thing, ie set to the back of our minds cos a) usually its the same each year & b) our individual risk of becoming severely unwell is low...
I'm not a psychologist, but we respond to change rather than magnitude.

This is fine if public health is there to provide the safety net. The question is, what do we want that net to achieve.
Living standards and medicine have reduced the baseline of excess deaths gradually over past decades...until recently! This is the power of public health 💪

However, progress with infections seems to be slow, with generally incremental improvements. The exception to this is when policy changes make a big difference, for example, addressing hospital acquired infections, or introducing the kids live nasal influenza vaccines 💙💙💙

With flu (and other respiratory viruses, of course!), however, we tolerate seasonal waves of infections that, even pre-pandemic, pre-austerity, put tremendous strain on the #NHS every year. Now, these waves councide with the perennial new kid on the block as well...

Seasonal flu undergoes changes due to mutations, and these mean that we update our Seasonal vaccines accordingly. This is possible because surveillance pucks up major strains circulating first in the Southern hemisphere well in advance. This is called "genetic drift"...

This is similar to what we see for SARS2, but much slower. The net effect is similar though: as a population we become less able to retain immunity vs infection, but many retain cross-protective responses that prevent the most severe disease...such as that caused by pandemic flu.

Such is the extent of this cross protection, and the longevity, that it has become accepted that we focus vaccines on the elderly and immunosuppressed, with more recent use of kids vaccines that both immunise and slow community transmission... apparently unacceptable to some 🙄

Indeed, it is now understood that had the pandemic H1N1 "Swine flu" occurred later than 2009, it may have been a disaster. This is because many elderly folk had experienced "Spanish" derived H1N1 during the early 20th century...younger people were more unwell, but coped better.

So, obviously a pandemic influenza, or indeed a panzootic as occurring right now with H5N1, is one where we have no prior immunity, usually due to either an animal virus changing, or the marriage of human and animal viruses by genetic reassortment on a "mixing vessel" like pigs.

This is a similar scenario to COVID, although the ensuing disease and immunology can differ.
But, the vast majority of severe seasonal flu and associated deaths occurs because of secondary bacterial pneumonia. Again, no top trumps, clinical impact is same whether "with or from".

Who is getting ill? Well, generally, those who are eligible but don't get vaccines, and younger kids...the majority of whom thankfully usually are OK in the end, but there's no such thing as a trivial trip to hospital for kids and their families...same applies for RSV etc.

A "bad" flu season can lead to 20k or more deaths as a result of this...whether with, or of...this, along with the huge pressure on the NHS it brings...which we seemingly accept.
Flu also causes "long flu", as well as other sequelae, but thankfully not as frequently as SARS2.

Yet, there's this disconnect between such massive and profound impact for flu, and the notion that it's a trivial illness to be dismissed, mistaken for the common cold (which itself is both complex and sometimes severe), or used to minimise a pandemic virus...
This, is folly.

2022 took the biscuit for me. We had a good match with the vaccine vs the main protagonist, H3N2, and we knew from the Southern hemisphere it was a nasty so and so...to be clear, years when the vaccine doesn't match are usually when the 💩 hits the fan...
We also had COVID...

BUT, where was the mass campaigns for adult and kids vaccines? Where was the drive to ensure schools were sorted AHEAD of the inevitable wave? Where was the concern that a large flu wave could lead to increases in associated diseases like iGAS?
No. Revert to type. 2019 again.

We can do SO much better.

Like them or loathe them, the mitigations in place to reduce SARS2 transmission effectively eliminated (NOT eradicated) influenza from the UK (and elsewhere) for two years...a strain of influenza B has even seemingly become extinct as a result...

This is due mainly to influenza being less inherently infectious compared with SARS2...
Now, this also meant that the usual number of people becoming immune post-infection didn't happen, increasing the susceptible pool...hence, we knew 2022 would be bad...and why more was needed.

As a result, massive wave, coincident with RSV AND SARS2, our already overburdened, understaffed, under resourced, and under valued (by some) NHS weathered a disaster as a result...more cases = more severe cases 😳

This was NOT due to individuals being more likely to experience severe disease, aka "immunity debt"...which is a nonsense, made-up and bizarre twist on the widely debunked hygiene hypothesis...ie, we don't need to live in pig swill to "train our immune muscles" as some may think.

So, the fact is that we allocate flu vaccines and take relatively little action to promote measures that will reduce spread. Vaccines are of course expensive, and a cost benefit assessment is done based upon allocated budgets.
But @CathNoakes reported that clean air saves £bn's.

Improved population scale mitigations would counter flu, COVID, RSV, pollution, CO2 impact on cognition etc @CovidPledge
Widespread vaccination would initially cost, but what benefits for the NHS and a healthy workforce?
Let's learn, let's improve, let's #vaccinesplus in future🙏