With the World Vaccine Congress Europe approaching, I’ve been reflecting on the themes that have shaped respiratory vaccine development this year. Even though I won’t be in Amsterdam myself, the meeting remains an important point of convergence for the scientific and regulatory discussions that influence how programmes evolve. The conversations coming out of it will matter, and I’m looking forward to hearing from hVIVO colleagues in attendance and the wider field as the next wave of thinking emerges.
Respiratory vaccine development is clearly entering a new phase. The urgency that defined the COVID period has shifted toward longer‑term questions about how we design, compare, and incorporate antigens targeting multiple pathogens. Europe tends to push these discussions further, and this year’s meeting will likely continue that trajectory.
Combination Strategies Are Becoming Central
One of the strongest currents in Washington — and one that will undoubtedly carry into Amsterdam — is the increasing focus on combination respiratory vaccines. Developers across platforms are now exploring combinations of influenza and COVID‑19 as well as RSV, hMPV, and parainfluenza. The scientific rationale is strong, but the development pathways are more complex.
Key questions remain around antigen selection, dosing strategies, frequency of administration, and how to choose appropriate comparators across regions. The discussions earlier this year between Moderna and the FDA highlighted how challenging these pathways become when multiple antigens and multiple standards of care converge in a single programme. Europe brings its own regulatory nuances, and those will be central to the conversation.
Despite the complexity, the direction of travel is clear. The burden of disease across RSV, hMPV, and parainfluenza is better understood than ever, and the industry increasingly recognises that these pathogens interact in ways that justify broader, more integrated vaccination strategies. The challenge now is generating evidence that is not only immunologically robust but also compelling from a burden‑of‑disease and advisory‑committee perspective.
Human Challenge Studies Are Becoming More Strategic
Another theme that continues to gain traction is the role of human challenge studies in respiratory vaccine development. The conversation has moved decisively from “if” to “how.” Challenge models are now widely recognised for their ability to generate early efficacy signals, differentiate symptomatic from asymptomatic infection, and refine endpoints or dosing regimens before moving into large field trials.
As combination vaccines become more complex, the value of controlled, high‑resolution human data increases. Sponsors are looking for ways to de‑risk programmes earlier, and challenge studies are becoming an essential part of that strategy.
Early Human Data Is Increasingly Important
For hVIVO, this direction aligns closely with the capabilities we’ve been building. The interest we saw in Washington — particularly around RSV, hMPV, and parainfluenza — reflects a broader industry shift toward early efficacy readouts, controlled comparisons, and deeper understanding of respiratory pathogens. Sponsors want to accelerate decision‑making and reduce uncertainty before committing to large Phase II and III programmes.
A consistent message this year has been that progress requires informed risk‑taking. In respiratory vaccine development, that means embracing new models, new endpoints, and new regulatory pathways — not waiting for perfect clarity before moving forward.
Efficacy demonstrated against one pathogen target within a combination vaccine does not guarantee equivalent performance against the other antigens. With variable community circulation rates for each pathogen, traditional field-based studies often struggle to effectively demonstrate efficacy against all vaccine components. Challenge studies solve this problem by directly testing the efficacy of a specific component of the vaccine. This enables sponsors to quickly re-risk later stage studies by gaining an early understanding of efficacy for each of the target pathogens.
Looking Ahead to Amsterdam
As Europe prepares to host the next major gathering of the vaccine community, the momentum is unmistakable. The scientific questions being asked, the regulatory challenges being debated, and the development strategies being explored all point toward a future where early, high‑fidelity human data becomes even more central to respiratory vaccine development.
That’s exactly where hVIVO is focused. The work ahead is complex, but the direction is right — and the momentum is real.