Annual theme 2025: vaccine-preventable diseases in humans

Vaccinations against COVID-19 were integrated into routine care in Germany in April 2023. However, evidence of the impact of seasonal vaccination remains limited.

To assess the clinical and economic impact of COVID-19 vaccination in routine care during the early SARS-CoV-2-endemic phase in Germany.

A retrospective cohort study using statutory health insurance data from two German federal states (Saxony and Thuringia), covering over 3 million individuals, was conducted. Adults aged ≥ 18 years vaccinated against COVID-19 between 1 September and 30 November 2023 were matched 1:1 with unvaccinated individuals using propensity scores. Outcomes during the 4-month follow-up included occurrence of SARS-CoV-2 infection, long COVID, other respiratory infections, hospitalisations, mortality, healthcare costs and indirect costs caused by sick leave. Rate and hazard ratios (RR, HR) with 95% confidence intervals (CI) were calculated. Sensitivity analyses tested robustness.

A total of 146,132 individuals (73,066 per group) were matched. COVID-19 vaccination was associated with reduced rates of long COVID (RR: 0.43; 95% CI: 0.26–0.70), respiratory infections (RR: 0.91; 95% CI: 0.87–0.95) and COVID-19-related hospitalisations (RR: 0.41; 95% CI: 0.31–0.54). All-cause mortality was 25% lower among COVID-19-vaccinated individuals (HR: 0.76; 95% CI: 0.70–0.82). Healthcare costs were lower in the vaccinated cohort, particularly for inpatient care, e.g. EUR 1 million savings in COVID-19-related hospitalisations. Indirect costs caused by sick leave were also reduced by EUR 1.3 million.

Seasonal COVID-19 vaccinations in routine care settings were associated with substantial clinical and economic benefits. These real-world findings support continued implementation of national immunisation recommendations during the endemic phase of SARS-CoV-2 circulation.

Vaccination of residents and healthcare workers (HCWs) against influenza in nursing homes is an important prevention strategy.

To describe trends in influenza vaccination coverage (VC) among HCWs working in nursing homes in France and measures implemented to support vaccination campaigns from 2007 to 2025, and to identify effectiveness of these measures.

We analysed data from seven nationwide cross-sectional studies conducted between seasons 2007/08 and 2024/25 and performed multivariate analysis using negative binomial regressions, to identify determinants.

National influenza VC among HCWs decreased from 37.2% (95% CI: 35.7–39.4) in 2007/08 to 24.2% (95% CI: 23.2–25.1) in 2024/25 (mean: 39,740 HCWs per season, 6 seasons). Vaccination coverage disparities by category of HCWs (2024/25 VC of physicians: 56.3%; nurses: 34.2%; nursing assistants: 19.3%) were observed throughout the period. Measures to promote influenza vaccination were less frequently implemented over time: support of vaccination campaigns by the management team (from 2018/19: 89% to 2024/25: 52%), implementation of collective (68% to 49%) or individual information sessions (19% to 9%), distribution of information on influenza vaccines (64% to 53%) or influenza (83% to 69%). Seven measures exhibited effectiveness in 2018/19 compared to only four in 2024/25, which had less effectiveness. Management teams highlighted the strong reluctance of HCWs to receive influenza vaccination.

Influenza VC among HCWs in nursing homes is marked by disparities among professional categories. To mitigate the decline in VC among HCWs, it is essential to implement effective measures to support the campaigns.

In autumn 2023, Spain recommended nirsevimab to all infants born after 1 April 2023, as catch-up or at-birth immunisation.

We estimated effectiveness of a single nirsevimab dose against respiratory syncytial virus (RSV) hospitalisations throughout two seasons in healthy term-born infants.

Cases were children born 1 April 2023 through 31 March 2024 after 35 gestation weeks without major comorbidities and hospitalised for RSV infection between 2023 immunisation campaign onset and 31 March 2025. We selected four healthy population-density controls per case, matched by province and birth date. Using target trial emulation, causal per-protocol effectiveness was estimated for catch-up (within 30 days of 2023 campaign onset) and at-birth immunisation (within 14 days of life) through cloning, censoring and inverse-probability-weighted conditional logistic regression.

We included 235/905 cases/controls for catch-up and 334/1,292 cases/controls for at-birth immunisation (first season), and 188/713 cases/controls for catch-up and 328/1,269 cases/controls for at-birth immunisation (second season). Two-season effectiveness was 64% (95% confidence interval (CI): 52–72) and 67% (95% CI: 59–74) for catch-up and at-birth immunisation, respectively, compared with 78% (95% CI: 70–84) and 84% (95% CI: 79–88) during first season and −8% (95% CI: −88 to 38) and 20% (95% CI: −21 to 46) during second season.

Nirsevimab was an effective long-term population-level intervention, decreasing RSV hospitalisations by two-thirds during the first two seasons of life. Effectiveness during second season was low or null, although it may be underestimated due to unavoidable survivor bias. The RSV hospitalisation rate among immunised children did not rebound in the second season.

Respiratory syncytial virus (RSV) is a leading cause of morbidity and mortality in young children and older adults. A long-acting anti-RSV monoclonal antibody (nirsevimab) and bivalent pre-fusion F-protein pregnancy vaccine became available to prevent RSV in young children in 2024; two RSV vaccines for adults ≥ 60 years were also available.

To report 2024 RSV epidemiology in Australia, identify risk factors for severe outcomes, and use and effectiveness of RSV immunisation products.

National sentinel hospital-based RSV surveillance was established in 2024, recruiting hospitalised laboratory-confirmed RSV cases and test-negative controls from 22 sites in a national hospital network (FluCAN-PAEDS).

Between April and December 2024, 3,998 subjects (3,415 children; 582 adults) were hospitalised with RSV. Most cases were infants < 12 months (n = 1,534; 38.4%); 1,661 (41.5%) had underlying medical conditions. Children < 6 months, First Nations children, those born preterm or with underlying medical conditions (cardiac, neurological, genetic and metabolic disease/disorders, immunosuppression) were at greatest risk of severe outcomes. Severe outcomes were more frequent in adults with malignancy, respiratory or cardiac disease. Nirsevimab effectiveness against hospitalisation in infants < 12 months in the two Australian jurisdictions with population-wide immunisation programmes was 83.1% (95% CI: 67.4–91.3). RSV vaccine use (pregnancy; adults ≥ 60 years) was limited, precluding effectiveness assessments.

National surveillance enabled timely 2024 data collection with the capability to evaluate effectiveness of immunisation products preventing RSV. Nirsevimab demonstrated comparable effectiveness to that in the northern hemisphere, informing Australia’s 2025 strategy. Evaluation to assess the impact of more widespread uptake of RSV prevention products continues.

In Scotland, the number of pertussis infections recorded in children in 2024 was the highest of any year in the last decade. The protective role of vaccination against severe infection and associated hospitalisations has not been assessed.

To investigate the effect of vaccination and sociodemographic factors on pertussis-related hospitalisations in Scottish children aged under 18 years.

In a retrospective cohort study, laboratory-confirmed pertussis cases from January 2013 to July 2024 were extracted from the national electronic surveillance system and linked to hospitalisation data from Scottish Morbidity Records and vaccination data from the national immunisations database. The outcome was a pertussis-associated hospitalisation. Multivariable logistic regression was used to calculate odds ratios (OR) for the association between vaccination status and hospitalisation, adjusted for age, sex, ethnicity and deprivation status.

There were 3,982 laboratory-confirmed cases of pertussis during the study period. Children fully vaccinated for age had significantly lower odds of hospitalisations than unvaccinated children (adjusted OR (aOR): 0.31; 95% CI: 0.21–0.46). Being partially vaccinated for age did not significantly reduce hospitalisations relative to unvaccinated children (aOR: 0.80; 95% CI: 0.47–1.33). In the univariable analysis, children living in the most deprived areas had significantly more hospitalisations than those in the least deprived areas (OR: 3.90; 95% CI: 2.41–6.56). This association was not significant when adjusted for the effect of vaccination (aOR: 1.47; 95% CI: 0.84–2.66).

Fully vaccinated children had significantly lower odds of hospitalisation, indicative of less severe disease. This emphasises the importance of fully vaccinating children according to the childhood immunisation schedule.