The review, led by Vivian Ibienebakabobo Promise of Bayelsa Medical University in Nigeria together with Ebinyo Rebecca Aseibai and Sylvester Chibueze Izah, is a scoping review: a systematic map of all the primary human evidence published between 1999 and 2025 linking vaccines to antibiotic use or microbiological resistance. Following Joanna Briggs Institute guidance and reported under the PRISMA-ScR framework, the team searched PubMed in June 2026, supplemented by Europe PMC, the WHO Global Index Medicus, Google Scholar and citation chaining. The initial search returned 7,433 records. After rigorous screening — with one reviewer conducting initial assessment and a second author independently verifying every inclusion — 74 primary studies made the final cut: 35 examining antibiotic use and 39 examining direct resistance outcomes.

The logic behind the vaccine-resistance connection is elegant. Antibiotic resistance is fundamentally a problem of selection pressure: the more antibiotics circulate in a population, the more opportunities bacteria have to evolve defenses. Vaccines attack that pressure at its source. By preventing infections in the first place, they eliminate the illnesses that trigger antibiotic prescriptions. By blocking transmission of vaccine-targeted strains, they reduce the pool of bacteria that can acquire or spread resistance genes. And by shrinking the total burden of disease, they lower the sheer volume of antibiotics dispensed across entire communities — including to people who were never vaccinated at all, through herd protection.

The influenza findings are the review’s most immediately actionable. Across multiple studies, flu vaccination generally reduced antibiotic exposure for respiratory infections — the category where inappropriate prescribing is most rampant, since clinicians and patients alike struggle to distinguish viral illness from bacterial. The effect was not universal: some trials returned null results, and seasonal variability in how well the vaccine matched circulating strains muddied the picture from year to year. But the overall signal was consistent enough for the authors to flag influenza vaccination as carrying the strongest evidence base for reduced prescribing. One striking quantitative example: an estimated 8 percent vaccine effectiveness against outpatient antimicrobial purchases, meaning the shot didn’t just prevent illness — it kept people out of pharmacies with prescriptions in hand.

Pneumococcal conjugate vaccines, which protect against Streptococcus pneumoniae, delivered perhaps the review’s most dramatic numbers. Introduced into childhood immunization schedules worldwide over the past two decades, these vaccines produced modest reductions in all-cause antibiotic use but much larger reductions when measured against specific syndromes. The indirect effects were substantial too: one study documented a 14.7 percent drop in otitis-related antimicrobial purchases — ear infections being a classic driver of pediatric antibiotic prescriptions. Most remarkable of all was the long-term United States surveillance data on resistant disease. Among children under five, nonsusceptible invasive pneumococcal disease fell from 43.9 cases per 100,000 to just 3.2 per 100,000 following vaccine introduction. That is not a marginal improvement. That is the near-erasure of an entire category of drug-resistant childhood infection.

The evidence extends well beyond the two usual suspects. An investigational maternal respiratory syncytial virus vaccine — given to pregnant women to protect their newborns — reduced infant antimicrobial prescribing by 12.9 percent, a finding with enormous implications as RSV immunization rolls out globally. Studies of rotavirus, COVID-19 and typhoid conjugate vaccines rounded out the picture, demonstrating that the vaccination-to-antibiotic pathway operates across respiratory, gastrointestinal and enteric disease alike. Each vaccine that prevents a common infection removes a predictable slice of antibiotic demand from the system, and the review makes clear that this mechanism is general, not an artifact of any single pathogen or product.

The authors are careful, however, not to oversell. Two significant limitations temper the conclusions. The first is serotype replacement: when a vaccine eliminates the pneumococcal strains it targets, other strains sometimes fill the ecological vacuum, and those replacements can themselves carry resistance. The second is ecological confounding — the difficulty of attributing population-level changes in resistance to vaccination alone when prescribing habits, diagnostic practices and infection control measures shift simultaneously. For total antimicrobial resistance burden, the review concludes, inference remains limited. The strongest claims are reserved for what the data actually support: reduced influenza-associated prescribing and dramatic declines in resistant vaccine-type pneumococcal disease.

Methodologically, the review is a model of transparency for its genre. The team prespecified a term-based prioritization step before detailed title, abstract and full-record assessment, charted data by vaccine type, population, study design, outcome and effect estimate, and used design-appropriate Joanna Briggs Institute quality domains to inform interpretation rather than to exclude studies outright. That inclusiveness is the point of a scoping review: rather than pooling effect sizes into a single meta-analytic estimate, it maps the terrain, revealing where the evidence is dense, where it is thin, and where the field should dig next. What emerges is a terrain with deep wells of evidence around influenza and pneumococcus, and promising but sparser coverage elsewhere.

The strategic implications are considerable. Antimicrobial resistance is projected to claim millions of lives annually in the coming decades, and the pipeline for genuinely novel antibiotics remains tragically thin. Stewardship programmes — which try to change prescribing behavior through guidelines, diagnostics and auditing — have shown only modest and uneven success. Vaccination offers something stewardship cannot: it reduces the demand for antibiotics structurally, before any prescription decision is ever made. In the authors’ framing, vaccine programmes should be treated as an upstream component of antimicrobial stewardship, working in concert with diagnostic stewardship and prescribing interventions rather than as a separate public health silo.

That integration, the review argues, requires sustained infrastructure: ongoing surveillance of pneumococcal serotypes, genomic monitoring of resistant strains, and continuous tracking of antimicrobial consumption at the population level. Without that monitoring, the gains documented here — the collapsing rates of resistant childhood pneumonia, the thousands of prescriptions never written after a flu shot — cannot be verified, maintained or extended to new vaccines as they arrive. The message for policymakers is deceptively simple: every dollar spent on immunization is quietly a dollar spent on preserving antibiotic effectiveness. The message for everyone else is simpler still. The next time you roll up your sleeve for a vaccine you consider routine, you are not just protecting yourself from a virus. You are helping to keep the antibiotics working — for the person beside you, and for everyone who will need them after.

Subject of Research: The effects of vaccination programmes on antibiotic consumption and antimicrobial resistance

Article Title: Effects of vaccination programmes on antibiotic consumption and antimicrobial resistance: a global scoping review

Article References: Promise, V. I., Aseibai, E. R., & Izah, S. C. (2026). Effects of vaccination programmes on antibiotic consumption and antimicrobial resistance: a global scoping review. BMC Infectious Diseases. https://doi.org/10.1186/s12879-026-14691-8

Image Credits: AI Generated

DOI: 10.1186/s12879-026-14691-8

Keywords: vaccination, antimicrobial resistance, antibiotic consumption, influenza vaccine, pneumococcal conjugate vaccine, antimicrobial stewardship, scoping review, public health, infectious diseases, RSV vaccine, serotype replacement, antibiotic prescribing

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

The study drew on nationwide survey data collected in 2025, covering children aged 1 to 17 years and their parents, with an additional linked sub-analysis spanning 2023 to 2025. The researchers defined regular parental AI use as consulting generative AI tools for health advice at least a few times per month. Among the 8,282 children and 5,170 parents analyzed, 1,278 children, or 15.4 percent, had parents who were regular AI health-advice users. This figure offers one of the first quantitative snapshots of how deeply chatbot-based health information seeking has penetrated everyday parenting in a developed health system.

To estimate the relationship between AI use and vaccination, the team employed modified Poisson regression, a statistical approach well suited to common binary outcomes such as whether a child received a particular vaccine. The models produced adjusted prevalence ratios, or aPRs, with 95 percent confidence intervals, while accounting for parent-level clustering and a battery of covariates. This clustering adjustment matters because some parents contributed more than one child to the dataset, and ignoring that structure would have artificially narrowed the confidence intervals and inflated the apparent precision of the estimates.

The headline result is a striking asymmetry across vaccines. For age-appropriate measles-rubella vaccination, the adjusted prevalence ratio was 1.02 with a confidence interval of 0.97 to 1.09, meaning the association was statistically indistinguishable from no difference at all. Yet for the three other vaccines examined, the associations were positive and statistically significant. Children of regular AI users had an adjusted vaccination rate of 76.6 percent for mumps compared with 72.7 percent among children of non-users, an aPR of 1.05. For influenza, the gap widened to 56.7 percent versus 49.0 percent, an aPR of 1.16. The largest difference appeared for COVID-19 vaccination, where 40.6 percent of children of AI-using parents were vaccinated compared with 30.9 percent of the rest, yielding an aPR of 1.31 with a confidence interval of 1.19 to 1.45.

Perhaps the most eye-catching finding emerged when the researchers stratified the COVID-19 result by parental age. Among parents younger than 30 years, the association was dramatically amplified, with an adjusted prevalence ratio of 2.58 and a confidence interval of 1.90 to 3.50, and a P value for interaction below 0.001. In practical terms, the youngest parents who regularly consulted AI for health advice had their children vaccinated against COVID-19 at more than two and a half times the rate of their peers who did not use AI, after adjustment. This age gradient suggests that the phenomenon is concentrated among the demographic most comfortable with conversational AI tools, and it hints that generative chatbots may function as a novel information gateway for a generation of parents who came of age alongside smartphones.

The authors did not stop at the cross-sectional snapshot. In a linked sub-analysis covering 2023 to 2025, they tested whether the associations persisted after adjusting for an available 2023 household-level prior vaccination marker and for vaccination attitudes. The associations survived this additional adjustment, which strengthens the case that the relationship is not simply an artifact of pre-existing vaccine-friendly households. Even so, the design remains observational and cross-sectional, and the authors are explicit that these are exploratory associations rather than evidence of causation.

Indeed, the study’s own interpretation is notably cautious. The researchers write that the findings may reflect digital health engagement, health information seeking, socioeconomic differences, or favorable attitudes, rather than vaccine-specific AI advice. In other words, parents who consult chatbots about their children’s health are likely a self-selected group: more digitally literate, more proactive about health information in general, and possibly more trusting of medical recommendations to begin with. The absence of an association with measles-rubella vaccination is consistent with this reading, because MR vaccination in Japan is a long-established routine immunization with near-universal promotion, leaving little room for any information source, AI or otherwise, to move the needle.

The contrast between the MR null result and the positive associations for the other three vaccines is itself informative. Mumps, influenza, and COVID-19 vaccines in Japan occupy a different position in the immunization landscape: they are either voluntary, more recently introduced for children, or subject to more fluctuating public debate. For these vaccines, parental decision-making is more contingent, and information-seeking behavior plausibly plays a larger role. A parent uncertain about whether to get their child a seasonal flu shot or a COVID-19 booster may find that a chatbot conversation supplies the nudge, the reassurance, or the practical details that tip the balance toward vaccination.

The study sits within a rapidly growing literature on AI and vaccine behavior. Prior evaluations have found that large language models generally align with World Health Organization positions on vaccine hesitancy and can counter common vaccination myths, while randomized trials of purpose-built vaccine chatbots have shown meaningful increases in HPV and influenza vaccination uptake. The Japanese findings add an observational, population-level dimension to this evidence base, suggesting that spontaneous, unguided AI use by parents correlates with higher uptake of vaccines where hesitancy or inertia is most common. At the same time, other research has flagged reliability and readability concerns in AI-generated pediatric health advice, underscoring that the quality of chatbot answers varies and that expert oversight remains essential.

For public health practitioners, the implications are twofold. First, generative AI has become a mainstream channel through which a meaningful minority of parents, roughly one in six in this sample, seek child health guidance, and that channel appears to lean toward vaccine-promoting rather than vaccine-skeptical behavior, at least in this Japanese cohort. Second, because the associations are strongest for vaccines where decision-making is most contested and among the youngest parents, health communicators may need to treat AI tools not merely as a risk to be mitigated but as an environment to be engaged. Whether the relationship is causal, and whether AI advice actively drives vaccination or simply marks out an already engaged population, will require longitudinal and interventional designs. Until then, this study stands as an early signal that the chatbot era is quietly reshaping how families navigate childhood immunization.

Subject of Research: Parental generative AI health-advice use and childhood vaccination uptake in Japan

Article Title: Associations between parental generative artificial intelligence health-advice use and child vaccination uptake in Japan: an exploratory cross-sectional study

Article References: Imanishi, Y., Iorini, M., Jwa, S., Sakamoto, M., Wada, I., Tabuchi, T., & Uchida, M. (2026). Associations between parental generative artificial intelligence health-advice use and child vaccination uptake in Japan: an exploratory cross-sectional study. World Journal of Pediatrics. https://doi.org/10.1007/s12519-026-01107-5

Image Credits: AI Generated

DOI: 10.1007/s12519-026-01107-5

Keywords: generative artificial intelligence, child vaccination, vaccine hesitancy, parental health information seeking, COVID-19 vaccine, influenza vaccine, mumps vaccine, measles-rubella vaccine, Japan, cross-sectional study, pediatrics, digital health

The research team set out to move beyond a long-standing limitation in the vaccine hesitancy literature. Previous studies attempting to explain why some people resist vaccination have overwhelmingly measured attitudes toward science and scientists through a single lens: trust. Yet contemporary debates about vaccines, playing out across news media, social platforms, and everyday conversation, suggest that hesitancy is rarely reducible to simple mistrust or doubts about the competence of researchers. People may accept that scientists are skilled while questioning whether science is beneficial, whether scientific institutions are unbiased, whether scientific claims are credible, and whether scientific interventions are prudent. The new study therefore disaggregated perceptions of science and scientists into these distinct dimensions and tested how each related to vaccine evaluations across the political spectrum.

The technical architecture of the analysis rested on the national probability sample, a methodological gold standard that allows findings from roughly 1,763 respondents to be generalized to the adult population of the United States with quantifiable confidence. Fielded in November 2024, the survey captured perceptions of three vaccines that occupy very different positions in American public health history and political discourse: the measles, mumps, and rubella vaccine, a decades-old mainstay of childhood immunization schedules; the seasonal influenza vaccine, renewed annually and broadly familiar to the public; and the COVID-19 vaccine, developed at unprecedented speed during a global emergency and subsequently swept into partisan controversy.

The results painted a consistent hierarchy of public confidence. Respondents rated the MMR vaccine as the safest and most effective of the three, a verdict that aligns with its long track record and its relative insulation from recent partisan battles. The COVID-19 vaccine received the lowest ratings on both dimensions, perceived as neither as safe nor as effective as its older counterparts. The influenza vaccine fell between these poles. This ordering matters because perceived safety and perceived effectiveness are the twin psychological pillars on which vaccine acceptance rests; when either erodes, uptake tends to follow, and the consequences ripple outward through community immunity and disease transmission.

Political affiliation emerged as a powerful organizing variable. Republicans generally reported less favorable perceptions of vaccine safety and effectiveness than Democrats, and the gap widened dramatically for the COVID-19 vaccine, confirming that the politicization of that vaccine during and after the pandemic left a durable imprint on public judgment. The MMR and influenza vaccines, by contrast, showed smaller partisan differences, suggesting that the polarization surrounding COVID-19 immunization is not simply a generalized Republican skepticism of all vaccines but a vaccine-specific phenomenon rooted in the particular political history of the pandemic response.

Perhaps the most illuminating findings concerned the specific dimensions of perceptions of science and scientists. Across all three vaccines, one factor stood out for its consistency: perceiving science as beneficial was the strongest and most reliable correlate of positive vaccine evaluations. Americans who saw science as delivering tangible advantages to society were markedly more likely to rate each vaccine as safe and effective, regardless of party. This pattern held for the MMR vaccine, the flu vaccine, and the COVID-19 vaccine alike, making the perceived benefit of science the single most robust psychological predictor in the entire analysis.

Other dimensions of scientific perception showed more nuanced, politically contingent effects. Perceiving scientists as unbiased mattered more in Republicans’ assessments of the COVID-19 vaccine’s effectiveness, but played a comparatively smaller role among Democrats in evaluations of the MMR vaccine’s effectiveness. Dr. Walter offered a pointed interpretation of this asymmetry, noting that the difference is likely the result of attacks on the integrity of scientists during the COVID-19 pandemic from the right, as opposed to prepandemic concerns about the MMR vaccine from the left. In other words, when a community has been told repeatedly that scientists cannot be trusted to be impartial, the perceived impartiality of scientists becomes the decisive question for that group, whereas older vaccine controversies rooted in different political traditions activate different concerns.

The study’s framework implies that vaccine communication strategies built solely on appeals to trust may be leaving important levers unused. If resistance extends beyond mistrust or doubts about scientists’ competence, then interventions that address whether science is viewed as beneficial, credible, unbiased, and prudent may reach audiences that trust-based messaging misses. The finding that perceived benefit is the most consistently associated factor suggests that communication emphasizing the concrete, tangible benefits of science and vaccines, from prevented illnesses to protected communities, may be particularly effective, especially when tailored to the specific concerns and political context of the audience being addressed.

Such tailoring is not a matter of partisan pandering but of diagnostic precision. The data indicate that a communication strategy optimized for a Democratic audience evaluating the MMR vaccine may be poorly suited to a Republican audience evaluating the COVID-19 vaccine, because the psychological pathways underlying those judgments differ. For the latter group, evidence and messaging that directly address the integrity and impartiality of the scientific enterprise may carry disproportionate weight. For audiences weighing older vaccines, reinforcing the everyday benefits that science delivers may be the more productive route. The authors conclude that understanding vaccine perceptions benefits from examining both political affiliation and the multidimensional perceptions of science and scientists, an approach that offers practical insights for guiding tailored communication strategies rather than one-size-fits-all campaigns.

The implications extend well beyond the three vaccines studied. As public health authorities confront resurgent measles outbreaks, seasonal influenza burdens, and the ongoing task of maintaining COVID-19 immunization coverage, the study provides an evidence-based map of where public confidence stands and why it varies. It demonstrates that the American public does not hold a single undifferentiated attitude toward science but a bundle of distinct perceptions, each with its own political geography and its own relationship to vaccine judgment. For researchers, the work models a more granular approach to measuring science attitudes. For practitioners, it delivers a clear message: the path to higher vaccine confidence runs through demonstrating the benefits of science, defending the integrity of scientists where it has been called into question, and meeting audiences where their political experiences have shaped what they doubt and what they believe.

Subject of Research: Political affiliation and perceptions of science and scientists in relation to perceived vaccine safety and effectiveness in the United States

Article Title: American Journal of Public Health study examines political differences in perceptions of vaccine safety and effectiveness

Article References: American Journal of Public Health study examines political differences in perceptions of vaccine safety and effectiveness. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: vaccine hesitancy, vaccine safety, vaccine effectiveness, political affiliation, perceptions of science, MMR vaccine, COVID-19 vaccine, influenza vaccine, public health, health communication, survey research, American Journal of Public Health

The research team, led by Hui Xu and corresponding author Lixin Hao of the National Immunization Program at China CDC, set out to answer a deceptively simple question: among adults with chronic diseases who are under regular medical care, how many actually follow the recommendation to be vaccinated against influenza each year? This question matters because most previous studies of vaccine uptake in China have focused on the general population or on specific groups such as older adults and health care workers. Far less is known about patients with chronic conditions who see their doctors regularly and who might therefore be expected to receive timely vaccination advice as part of routine care.

To investigate, the researchers conducted a questionnaire-based cross-sectional survey in November 2022. The study drew on de-identified data from the China Influenza Vaccination Literacy Evaluation Project, an effort originally carried out by the Chinese Association on Vaccination in 2022 and formally authorized for secondary analysis. The analysis was approved by the Institutional Review Board of China CDC, and all data were anonymized through the removal of direct identifiers and the aggregation of demographic variables to prevent re-identification. Crucially, the survey targeted patients who had been selected by their own physicians and who were being actively managed for chronic diseases as outpatients, meaning that every participant had an established doctor-patient relationship at the time of the survey.

The questionnaire assessed participants’ knowledge about influenza and influenza vaccination, along with a range of demographic, economic, and health-related factors. The primary outcome was patient-reported receipt of the influenza vaccine, which the researchers treated as a measure of compliance with vaccination recommendations. In total, 547 subjects completed the survey. The team used chi-square tests to examine associations between individual factors and vaccination status in univariate analyses, and then applied logistic regression to identify the independent predictors of compliance while adjusting for other variables.

The headline result is sobering. Only 19.6 percent of the 547 outpatients with chronic diseases reported receiving an influenza vaccine annually. In other words, roughly four out of five patients for whom annual influenza vaccination is explicitly recommended were not following that recommendation, despite having regular contact with the health care system. Because these patients were physician-selected and already embedded in ongoing care, the finding suggests that the problem is not simply a matter of hard-to-reach populations. Even patients with consistent medical follow-up are largely missing out on a preventive intervention that could reduce their risk of influenza-related hospitalization and death.

The logistic regression analysis identified three factors that were independently and positively associated with compliance. The strongest was economic: patients with an annual household income of at least 150,000 yuan had more than six times the odds of annual vaccination compared with lower-income patients, with an odds ratio of 6.619 and a 95 percent confidence interval of 2.552 to 17.167. This pronounced income gradient points to cost as a likely barrier, since influenza vaccination in China is generally self-paid for most adults rather than covered by routine public financing. Patients who recalled receiving a recommendation from their doctor were also far more likely to be vaccinated, with an odds ratio of 4.223 (95 percent confidence interval, 2.051 to 8.693), underscoring the persuasive power of a direct physician endorsement.

The third independent predictor was knowledge. Patients who scored higher on the survey’s measure of basic vaccine knowledge had roughly two and a half times the odds of annual vaccination, with an odds ratio of 2.474 (95 percent confidence interval, 1.377 to 4.446). This association suggests that understanding what influenza is, how the vaccine works, and why it matters for people with chronic conditions translates into concrete preventive behavior. Taken together, the three predictors sketch a coherent picture: patients who can afford the vaccine, who hear about it from a trusted clinician, and who understand its value are the ones who get it. Patients lacking any one of these advantages tend to fall through the cracks.

From a technical standpoint, the study’s design has both strengths and limitations worth noting. By restricting the sample to patients with established doctor-patient relationships, the researchers deliberately tested compliance in a setting where the recommendation should be easiest to deliver, which makes the low uptake figure all the more consequential. The reliance on patient-reported vaccination status, rather than verified immunization records, introduces the possibility of recall bias, and the cross-sectional design means the associations identified cannot establish causation. The modest sample size of 547, drawn from a single survey wave in November 2022, also means the results may not generalize to every region or clinical setting in China. Nevertheless, the consistency of the income, physician-recommendation, and knowledge effects with broader vaccine behavior research lends credibility to the central conclusion.

The authors conclude that compliance with influenza vaccination recommendations among outpatients with chronic medical conditions and established doctor-patient relations is suboptimal, and they highlight three corresponding priorities for policy and practice. First, appropriate financing mechanisms are needed so that the cost of influenza vaccination does not fall disproportionately on individuals, given the sixfold advantage observed among higher-income patients. Second, physicians should be encouraged and supported to recommend influenza vaccination to their chronic disease patients during routine visits, since a remembered recommendation roughly quadrupled the odds of uptake. Third, providing clear, accessible information about influenza and influenza vaccination can build the baseline knowledge that appears to underpin informed decisions about prevention.

The implications extend beyond China’s borders. Chronic diseases are rising worldwide, and seasonal influenza continues to exact a heavy toll on vulnerable patients in every health system. The study’s central lesson is that clinical guidelines alone do not change behavior; they must be paired with affordable access, active clinician engagement, and effective health communication. For the roughly 80 percent of Chinese chronic disease outpatients currently going unvaccinated each year, the difference between a routine doctor’s visit that includes a vaccination recommendation and one that does not may ultimately determine whether they spend the influenza season at home or in a hospital bed. The research was funded by the Integrated Disease Prevention and Control program of the Chinese Centre for Disease Control and Prevention, whose funders played no role in data collection, analysis, interpretation, or manuscript preparation, and the article is published open access under a Creative Commons Attribution 4.0 license.

Subject of Research: Influenza vaccination compliance among outpatients with chronic diseases in China

Article Title: Compliance with influenza vaccination recommendations among outpatients with chronic diseases in China in 2022

Article References: Xu, H., Hou, Q., Jia, Y., Yang, Y., Wang, Q., Ma, R., & Hao, L. (2026). Compliance with influenza vaccination recommendations among outpatients with chronic diseases in China in 2022. BMC Infectious Diseases. https://doi.org/10.1186/s12879-026-14553-3

Image Credits: AI Generated

DOI: 10.1186/s12879-026-14553-3

Keywords: influenza, influenza vaccine, vaccination compliance, chronic disease, outpatients, China, China CDC, cross-sectional study, logistic regression, health policy, immunization, public health

The study, published in EClinicalMedicine by Yan Xie, Taeyoung Choi, and Ziyad Al-Aly of the VA St. Louis Health Care System, drew on the electronic health records of the U.S. Department of Veterans Affairs, an integrated system spanning 172 health systems, 142 hospitals, and 1,241 outpatient sites. The researchers identified 1,401,492 participant-trials among veterans who attended an in-person primary care visit between September 15, 2025, and February 28, 2026, the period when the seasonal vaccine was widely available across the VA. Within this cohort, 526,350 participant-trials involved vaccination at the index visit and 875,142 involved no vaccination at that visit or during follow-up, and the cohort collectively contributed more than 635,000 person-years of observation, with a median follow-up of roughly six months.

What sets this analysis apart from the interim estimates issued by surveillance networks in England, Canada, and the United States is its design. Most seasonal vaccine effectiveness figures come from test-negative case-control studies, which compare vaccination rates between patients who test positive and those who test negative for influenza among people seeking care for acute respiratory illness. These designs efficiently control for care-seeking and testing behavior but estimate only relative protection among tested patients. The VA team instead emulated a target trial, a framework that asks what would happen if eligible people were, hypothetically, randomized to vaccination or no vaccination at a real clinical encounter. Because vaccination occurs throughout the season while influenza activity rises and falls, the investigators did not run a single trial spanning the entire season. They instead emulated 24 sequential 7-day trials, assigning vaccination status at the start of each window and following vaccinated and unvaccinated participants concurrently so that both groups faced the same circulating viruses at the same calendar time.

This structure was engineered to blunt two well-known distortions in observational vaccine research. Immortal time bias arises when follow-up time during which a person cannot experience the outcome is misattributed to one group, and healthy-vaccinee bias arises because people who choose to get vaccinated tend to be healthier and more engaged with care than those who do not. To reduce the latter, the team restricted eligibility to veterans with a primary care visit in the previous 18 months, guaranteeing comparable engagement with the health system, and excluded participant-visits involving acute illness, recent hospitalization, end-of-life care, advanced organ failure or cancer, recent surgery, and very high predicted short-term risks of hospitalization or death. The result was a comparison between people who plausibly could have been vaccinated and people who plausibly could have remained unvaccinated at the same visit.

Statistical refinement went further. The researchers applied marginal structural models with inverse-probability weighting, estimating propensity scores from a comprehensive covariate set that included demographics, comorbidities, frailty indices, laboratory values, healthcare utilization, vaccination histories across five prior influenza seasons, COVID-19 vaccination records, and algorithmically selected high-dimensional variables drawn from diagnoses, medications, laboratory results, and procedures. Veterans in the unvaccinated group who later received the vaccine were censored, with time-varying inverse probability of censoring weights correcting for the informative nature of that departure. Outcomes were strictly defined by laboratory confirmation: an influenza-associated emergency department or urgent care visit within one day of a positive test, or a hospitalization within 30 days of a positive test.

The headline numbers were sobering but far from discouraging. Vaccination was associated with a vaccine effectiveness of 22.25 percent against laboratory-confirmed influenza-associated emergency department visits, 31.84 percent against influenza-associated hospitalizations, and 21.95 percent against the composite of the two outcomes. In absolute terms, vaccination prevented approximately five emergency department visits and one hospitalization per 10,000 vaccinated persons over the follow-up period. Protection appeared consistent across time windows, with effectiveness against the composite outcome of roughly 21 to 24 percent during the intervals from 31 to 120 days after vaccination, and it held across prespecified subgroups defined by age, split at 65 years, and by immunocompromised status.

To gauge how much the subclade K mismatch mattered, the researchers ran the identical design on the 2024–2025 season. The contrast was clear: effectiveness in the prior season reached 31.03 percent against emergency department visits, 48.57 percent against hospitalizations, and 32.15 percent against the composite outcome. The ratio between seasons worked out to roughly 0.7, meaning relative effectiveness in 2025–2026 was about 30 percent lower than in the year before, a statistically significant decline consistent with the antigenic drift of subclade K. Yet the direction of benefit remained firmly positive, echoing interim estimates from the CDC VISION network, which reported about 30 percent protection against adult influenza-associated hospitalization, and from England and Canada, which found meaningful if reduced protection against medically attended H3N2 illness.

The authors deployed an unusually thorough robustness program. Thirteen sensitivity analyses varied the follow-up horizon, cohort exclusion criteria, outcome definitions, target populations, model specifications, weight truncation thresholds, grace periods, and landmark exposure definitions, and the estimates held steady throughout. Negative outcome control analyses provided an additional check for residual confounding: vaccination showed no association with all-cause hospitalization within 14 days of follow-up or all-cause death within the same window, exactly the null results expected if the design were not systematically biased. These controls cannot prove the absence of confounding, but they strengthen confidence that the observed protection reflects a genuine vaccine effect rather than an artifact of who chooses to be vaccinated.

Limitations remain. The VA population skews older, whiter, and more male than the general United States population, which may limit generalizability. Outcomes required laboratory confirmation within VA data, so infections tested or treated elsewhere were likely missed, meaning the absolute reductions probably represent a lower bound on the vaccine’s real-world impact. Vaccinations received outside the VA system may also have been incompletely captured, a form of misclassification that would tend to bias effectiveness estimates downward. The study did not evaluate influenza-associated death, because event counts were too small for adequate statistical power, nor did it estimate effectiveness against specific viral subtypes separately.

The public health message, however, comes through clearly. Even in a season when the predominant virus drifted away from the vaccine strain after strain selection, vaccination continued to reduce emergency department visits and hospitalizations attributable to laboratory-confirmed influenza. Given that seasonal influenza causes an estimated 9.4 million to 51 million illnesses, 120,000 to 710,000 hospitalizations, and 6,300 to 52,000 deaths annually in the United States, absolute reductions of even a few events per 10,000 people translate into substantial averted morbidity across the tens of millions of doses administered each year. The findings argue against letting an imperfect antigenic match undermine vaccination campaigns, and they make the case for timely, season-specific effectiveness monitoring using complementary designs. As the authors conclude, the 2025–2026 vaccine was less effective than its predecessor by roughly 30 percent in relative terms, but it still did its most important job: keeping veterans out of emergency departments and hospital beds during a challenging influenza season.

Subject of Research: Real-world effectiveness of the 2025–2026 seasonal influenza vaccine against influenza-associated emergency department visits and hospitalizations among U.S. veterans during an H3N2 subclade K-dominated season

Article Title: Effectiveness of the 2025–2026 seasonal influenza vaccine among U.S. veterans: an observational study

Article References: Xie, Y., Choi, T., & Al-Aly, Z. (2026). Effectiveness of the 2025–2026 seasonal influenza vaccine among U.S. veterans: an observational study. eClinicalMedicine, 100, Article 104183. https://doi.org/10.1016/j.eclinm.2026.104183

Image Credits: AI Generated

DOI: 10.1016/j.eclinm.2026.104183

Keywords: influenza vaccine, vaccine effectiveness, H3N2 subclade K, target trial emulation, Veterans Affairs, antigenic drift, hospitalization, emergency department, observational study, marginal structural models, 2025–2026 season, public health