Immuniser Lyon was conceived as a coordinated, locally tailored effort to promote vaccination across the French city and its surrounding department, the Rhône. Rather than imposing a single top-down message, the initiative wove together actions adapted to local contexts: outreach in neighborhoods, engagement with pharmacies and general practitioners, and targeted communication aimed at groups with historically low coverage. The program’s architects bet on a simple premise—that proximity and local trust can accomplish what broad national messaging sometimes cannot. The new study set out to test whether that bet paid off in measurable terms.

The research team took a comparative approach, tracking two very different vaccines over two very different time horizons. For human papillomavirus (HPV) vaccination, which primarily targets adolescents, they analyzed coverage trends in the Rhône area from 2010 through 2022. For influenza vaccination, which is recommended annually for adults aged 65 and older, they examined the period from 2016 to 2020. Both analyses compared the Rhône against the rest of the neighboring Auvergne-Rhône-Alpes (ARA) region, using binomial log-linear models to quantify differences in uptake over time.

The HPV results tell a story of national dynamics dominating the picture. Vaccine coverage in the Rhône and the wider ARA region followed strikingly similar trajectories: after a nationwide decline that began in the mid-2010s—a period marked by public controversy over the HPV vaccine in France—uptake began climbing again from 2015 onward, and both areas rose in parallel through 2022. The researchers found no evidence that Immuniser Lyon had accelerated HPV uptake beyond what broader national trends would predict. This is not necessarily a failure of the local program; HPV vaccination in France is largely driven by national policy shifts, including the gradual extension of school-based vaccination recommendations and growing public confidence in the vaccine’s safety.

The influenza findings, however, paint a different picture. Among adults aged 65 and older—the group for whom seasonal flu poses the greatest risk of severe complications and death—vaccine coverage in Lyon in 2020 reached 64.5 percent, significantly higher than the 59.2 percent observed in the rest of the ARA region. The difference corresponds to an odds ratio of 1.25, with a 95 percent confidence interval of 1.24 to 1.26 and a p-value below 0.001, indicating that the gap is statistically robust rather than a product of random variation. In practical terms, roughly one in twenty additional older adults in Lyon was vaccinated compared with their counterparts elsewhere in the region.

What makes this gap notable is its timing and persistence. Influenza vaccination campaigns in France are largely standardized nationally, with the same vaccines, the same recommendations, and the same eligibility criteria applying across regions. If the difference in Lyon were driven by demographics alone—say, an older or wealthier population—the gap would likely be smaller or inconsistent over time. Instead, the researchers observed a pattern consistent with a potential contribution from Immuniser Lyon’s sustained local actions, which included pharmacist-led outreach, targeted reminders, and community-level engagement with older residents. The study’s authors are careful to frame this as a consistency check rather than proof of causation; the observational design cannot rule out confounding factors. But the alignment between the program’s activities and the observed uptake pattern is difficult to dismiss.

The contrast between the two vaccine outcomes offers a nuanced lesson for public health planners. HPV vaccination in France operates within a highly centralized policy framework, where national decisions about school-based programs and recommendation schedules shape coverage far more than local initiatives can. In that context, Immuniser Lyon’s HPV results simply mirror national trends—hardly surprising. Influenza vaccination, by contrast, depends heavily on individual annual decisions, repeated year after year, and on the accessibility of vaccination points within communities. This is precisely the terrain where local, sustained, relationship-based interventions can make a difference. Pharmacists, general practitioners, and community health workers in Lyon were able to reach older adults in ways that a national letter or television campaign might not.

The study also highlights the value of long-term evaluation. Eight years of data allowed the researchers to distinguish between short-term fluctuations and durable trends, and to compare the Rhône against a demographically similar neighboring region rather than against an abstract national average. This kind of longitudinal, geographically grounded analysis is rare in vaccination research, where programs are often evaluated over one or two seasons and where comparison regions are difficult to define. The binomial log-linear modeling approach, while statistically conventional, was applied with enough granularity to detect modest but meaningful differences in coverage—differences that would be invisible in coarser analyses.

For policymakers, the implications are cautiously optimistic. Local initiatives like Immuniser Lyon are not a substitute for national immunization strategy, but they appear capable of complementing it in specific, measurable ways—particularly for vaccines that require repeated, individual-level engagement. The findings suggest that cities and regions with the resources and political will to sustain multi-year vaccination programs may achieve incremental gains in coverage among hard-to-reach or hesitant populations. As France and other countries continue to grapple with vaccine hesitancy and uneven coverage, the Lyon experience offers a template: invest locally, measure rigorously, and be patient with the timeline. Eight years is a long commitment, but the data suggest it may be exactly the kind of commitment that moves the needle.

Subject of Research: Evaluation of the Immuniser Lyon local vaccination initiative and its association with HPV and influenza vaccine coverage trends in the Rhône area of France

Article Title: Assessing a local vaccination initiative: Eight years of “Immuniser Lyon” in France

Article References: Dessemon, J., Saux, R., Elias, C., Ronnaux-Baron, A.-S., Malachane, A. S., Pamies-Jeantet, S., Soubeyrand, B., Roy, P., & Vanhems, P. (2026). Assessing a local vaccination initiative: Eight years of “Immuniser Lyon” in France. PLOS Global Public Health, 6(10), e0007468. https://doi.org/10.1371/journal.pgph.0007468

Image Credits: AI Generated

DOI: 10.1371/journal.pgph.0007468

Keywords: Immuniser Lyon, vaccination, HPV vaccine, influenza vaccine, vaccine coverage, France, public health, Auvergne-Rhône-Alpes, older adults, vaccine hesitancy, local health initiatives, PLOS Global Public Health