I am 45, which means I’ve now had my third Covid vaccine. The experience of getting that injection crystallises a thought: Britain is starting to take the miracle of vaccination for granted, and that spells trouble for Boris Johnson.

I don’t use that word ‘miracle’ lightly. The development and distribution of working vaccines with such speed and scale is surely a historical event, and one that should give both big-state left-wingers and the free-market right pause for thought, since it relied on the partnership between public and private.

The politics of the vaccine have always been slightly under-appreciated in the Westminster village. The Hartlepool by-election, for instance, was undoubtedly another moment of historical importance, but I suspect future historians will give the vaccine effect more credit for the result than many contemporary accounts do.

But enough about history. Let’s talk about me.

I got my third jab at the same GP surgery that did the first two, in March and May. That meant standing in the same queue with people drawn from the same cohort: 40-something residents of Tooting and Balham in south London.

Those first two visits were very cheery. After a grim winter of lockdowns and despair, who could fail to smile at the jab that might mean freedom and a return to some sort of normal? So queuing felt like the continuation of the Thank You NHS-clapping on the doorstep of the early pandemic. That meant smiles and effusive thanks for the volunteers and staff running the vaccination centre. And stickers: in what other circumstances would adults proudly sport ‘I’ve had my job’ stickers designed for kids?

This time, not so much. Maybe it was the damp and the cold, but the bonhomie was definitely gone. Instead of thanks there were mild grumbles about the queue, the lack of communication, and especially about the advice to wait at the surgery for 15 minutes after the injection in case of after-effects. There were no stickers, and I didn’t hear anyone ask for one.

I don’t want to overstate this or overinterpret it: it was one visit to one surgery. But I think that dissipation of gratitude and relief is also visible in the national mood and political debate. The vaccine programme just isn’t a thing any more. It’s become routine, something that can be taken for granted, much as that original industrial-scientific miracle is now a mundane part of our recent past. Jabs gave Boris a bounce, but something that bounces up must eventually come down again.

This is quite normal, of course — there is generally little gratitude in politics. Winners are usually politicians who tell the best story about the future, not the past, which is why it’s never wise to write off Boris Johnson, a chronic optimist and first-class storyteller.

For now though, the evaporation of that temporary gratitude is, I think, inadequately explored in current political conversation. Yes, the Prime Minister has made horrible and largely unforced errors over sleaze, and — more importantly — the cost of living is rising.

But an overlooked reason those things are hurting a politician who has previously looked invulnerable to mortal weapons is that the golden glow of the jabs miracle is wearing off. Vaccine efficacy wanes in more ways than one.