Even when playing to the casual observer, it is obvious how entrancing the five-piece become when united in the chaos of performance. It is this crucial magic that has kept the rockers relevant from 2011 to 2022 and beyond, and their evolving fan base is visible evidence of that. "There's always been a part of me that's scared that every time we go out, it's finally going to be the tour where we walk out, and the barrier is going to be dominated by people in their forties and fifties," Justin admits. "Because then, you're stagnating. Ultimately, kids have the best taste in music. They're the ones who are most heavily invested in it, emotionally and from a lifestyle perspective. Once you lose them, it's a melancholic spiral."

This focus on youthful energy – something the rock outfit are best known for – is certainly not limited to their audience, but a global inevitability; one that artists don't necessarily push for, but can't avoid even if they wanted to. "I don't think it's conscious, but it's more something you're always aware of. I'm always amazed when I see pictures from a Green Day, Red Hot Chili Peppers or Muse show – there's always teenagers. The majority of people in a Green Day mosh pit are 15 or 16, and that's a band that's been around for 35 years."

The kids can appreciate the classics, too, as proven statistically by the recent achievement of 'If You Wanna' hitting 100 million streams on Spotify – something that they know wasn't strictly down to them. "It's such a silly number, such a silly thing, though it is a nice landmark. This summer, more than any that's come before, has compounded to me the idea that that song in particular, specifically in the UK, has become bigger than the band," he agrees. "People might know and like that song without even knowing who we are. I think it's crossed that boundary."

Not all groups cyclically reinvent or rebrand themselves in the way that The Vaccines have done gradually in response to their own tastes, as old hits can sustain their impact if they're done right, as Justin comments. "An album isn't for the month it comes out; it's for the decade to follow." This much is clearly true based on the continued support for The Vaccines' own debut, but the more interesting question is – how does that impact the process behind new projects?

Right now, then, the indie-rockers are clearly most thrilled by throwing this energy into a bubbly new style that doesn't sacrifice any of their discography's weight on recent EP 'Planet of the Youth', a follow-up punch that caught listeners off-guard as they recover from 'Back In Love City'. "I thought of it as Love City 1.2," he declares. "I imagine a house band in love city, much like the Star Wars cantina band, being in a casino performing the music from EP. We took that same palette and pushed it even further for the purpose of this release, but not necessarily as indication of anything we're looking at next."

Even if they do decide to follow an entirely new direction in their subsequent pursuits, the passion for the raw energy here and its bold layers of production is unwavering. "This EP is one of my favourite recordings that we've ever done," bassist Árni Árnason announces. "We made it super quickly, and the whole thing is very bouncy and deliberate, full of quick decisions – I love it."

Justin and Árni agree that the palpable excitement felt elusive on stage, as if the recording approach left holes that translated awkwardly, and that this experience is continuing to inform the delayed blossoming of youthful innocence into artful consideration.

The process involved definitely informs that as well. "We always try to make sure that we do something that's fun for us," Árni adds. "You can make albums in a really boring way if you want to, but we like to keep changing and never using the same studio twice. Just that process alone informs the sound and direction of the next album."

Speaking of which – despite an overwhelming flow of output from The Vaccines in the last twelve months, there are no plans to slow down just yet. In fact, album number six is already in its early stages of development. "There are songs written but not yet songs rehearsed or recorded, so how it comes out remains very much to be seen," Young hesitantly confirms. "We're at that point where we're thinking and talking about this kind of stuff every waking minute, so we're trying to formalise this enthusiasm right now. I think we can pre-emptively say there'll be a new record next year; I'll be surprised if we don't get there."

"Let's just commit to it now; why not?" Árnason gleefully throws in. Whatever you expected from The Vaccines, a lapse in momentum is never on the cards. The Vaccines' EP 'Planet Of The Youth' is out now.