Using a common protocol across seven countries in the European Union/European Economic Area, we estimated XBB.1.5 monovalent vaccine effectiveness (VE) against COVID-19 hospitalisation and death in ≥65-year-olds, during October-November 2023. We linked electronic records to construct retrospective cohorts and used Cox models to estimate adjusted Hazard Ratios and derive VE. VE for COVID-10 hospitalisation and death was, respectively, 67% (95%CI: 60-72) and 68% (95%CI: 44-82) in 65–79-year-olds, and 64% (95%CI: 49-75) and 74% (95%CI: 56-85) in ≥80-year-olds. Results indicate that periodic vaccination of individuals ≥65 years has an ongoing benefit, and support the current vaccination strategies in the EU/EEA.

We conducted a multicentre hospital-based test-negative case–control study to measure vaccine effectiveness (VE) against PCR-confirmed influenza in adult patients with severe acute respiratory infection (SARI) during the 2022/23 influenza season in Europe. Among 5547 SARI patients ≥18 years, 2963 (53%) were vaccinated against influenza. Overall VE against influenza A(H1N1)pdm09 was 11% (95%CI: -23–36); 20% (95%CI: -4–39) against A(H3N2) and 56% (95%CI: 22–75) against B. During the 2022/23 season, while VE against hospitalisation with influenza B was >55%, it was ≤20% for influenza A subtypes. While influenza vaccination should be a priority for the upcoming season, improved vaccines against influenza are needed.

Influenza A(H3N2) viruses dominated early in the 2022–23 influenza season in Europe, followed by higher circulation of influenza A(H1N1)pdm09 and B viruses. The VEBIS primary care network estimated the influenza vaccine effectiveness (VE) using a multicentre test-negative study. Primary care practitioners collected information and specimens from patients consulting with acute respiratory infection. We measured VE against any influenza, influenza (sub)type and clade, by age group, by influenza vaccine target group and by time since vaccination, using logistic regression. We included 38,058 patients, of which 3,786 were influenza A(H3N2), 1,548 influenza A(H1N1)pdm09 and 3,275 influenza B cases. Against influenza A(H3N2), VE was 36% (95%CI: 25–45) among all ages, ranged between 30% and 52% by age group and target group. VE against influenza A(H3N2) clade 2b was 38% (95% CI: 25–49). Overall, VE against influenza A(H1N1)pdm09 was 46% (95%CI: 35–56) and ranged between 29% and 59% by age group and target group. VE against influenza A(H1N1)pdm09 clade 5a.2a was 56% (95% CI: 46–65) and 79% (95% CI: 64–88) against clade 5a.2a.1. VE against influenza B was 76% (95%CI: 70–81), overall; 84%, 72% and 71% among 0–14-year-olds 15–64-year-olds and those in the influenza vaccination target group, respectively. VE against influenza B with a position 197-mutation of the hemagglutinin (HA) gene was 79% (95% CI: 73–85) and 90% (95% CI: 85–94) without this mutation. The 2022–23 end-of-season results from the VEBIS network at primary care level showed high VE among children and against influenza B, with lower VE against influenza A(H1N1)pdm09 and A(H3N2).

Background: Within the ECDC-VEBIS project, we prospectively monitored vaccine effectiveness (VE) against COVID-19 hospitalisation and COVID-19-related death, using electronic health registries (EHR), between October 2021 and November 2022, in community-dwelling residents aged 65–79 and ≥80-years in six European countries. Methods: EHR linkage was used to construct population cohorts in Belgium, Denmark, Luxembourg, Navarre (Spain), Norway and Portugal. Using a common protocol, for each outcome (hospitalisation and death), VE was estimated monthly over eight-week follow-up periods, allowing one month-lag for data consolidation. Cox proportional-hazards regression models were used to estimate adjusted hazard ratios (aHR) and VE=(1 – aHR) x100. Site-specific estimates were pooled using random-effects meta-analysis. Results: For ≥80-years, VE against COVID-19 hospitalisation decreased from 66.9% (95%CI: 60.1; 72.6) to 36.1% (95%CI: -27.3; 67.9) for the primary vaccination and from 95.6% (95%CI: 88.0; 98.4) to 67.7% (95%CI: 45.9; 80.8) for the first booster. Similar trends were observed for 65-79-years. The second booster VE against hospitalisation ranged between 82.0% (95%CI: 75.9; 87.0) and 83.9% (95%CI: 77.7; 88.4) for the ≥80-years and between 39.3% (95%CI: -3.9; 64.5) and 80.6% (95%CI: 67.2; 88.5) for 65-79-years. The first booster VE against COVID-19-related death declined over time for both age groups, while the second booster VE against death remained above 80% for the ≥80-years. Conclusions: Successive vaccine boosters played a relevant role in maintaining protection against COVID-19 hospitalisation and death, in the context of decreasing VE over time. Multi-country data from EHR facilitate robust near-real-time monitoring of VE in the EU/EEA and supports public health decision-making.

Background: In 2021–22, influenza A viruses dominated in Europe. The I-MOVE primary care network conducted a multicentre test-negative study to measure influenza vaccine effectiveness (VE). Methods: Primary care practitioners collected information on patients presenting with acute respiratory infection. Cases were influenza A(H3N2) or A(H1N1)pdm09 RT-PCR positive and controls were influenza virus negative. We calculated VE using logistic regression, adjusting for study site, age, sex, onset date, and presence of chronic conditions. Results: Between week 40 2021 and week 20 2022, we included over 11,000 patients of whom 253 and 1595 were positive for influenza A(H1N1)pdm09 and A(H3N2), respectively. Overall VE against influenza A(H1N1)pdm09 was 75% (95%CI: 43–89) and 81% (95%CI: 44–93) among those aged 15–64 years. Overall VE against influenza A(H3N2) was 29% (95%CI: 12–42) and 25% (95%CI: -41–61), 33% (95%CI: 14–49) and 26% (95% CI: -22 to 55) among those aged 0–14, 15–64 and over 65 years, respectively. The A(H3N2) VE among the influenza vaccination target group was 20% (95%CI: -6–39). All 53 sequenced A(H1N1)pdm09 viruses belonged to clade 6B.1A.5a.1. Among 410 sequenced influenza A(H3N2) viruses, all but 8 belonged to clade 3C.2a1b.2a.2. Discussion: Despite antigenic mismatch between vaccine and circulating strains for influenza A(H3N2) and A(H1N1)pdm09, 2021–22 VE estimates against circulating influenza A(H1N1)pdm09 were the highest within the I-MOVE network since the 2009 influenza pandemic. VE against A(H3N2) was lower than A(H1N1)pdm09, but at least one in five individuals vaccinated against influenza were protected against presentation to primary care with laboratory-confirmed influenza.

Background Claims of influenza vaccination increasing COVID-19 risk are circulating. Within the I-MOVE-COVID-19 primary care multicentre study, we measured the association between 2019–20 influenza vaccination and COVID-19. Methods We conducted a multicentre test-negative case-control study at primary care level, in study sites in five European countries, from March–August 2020. Patients presenting with acute respiratory infection were swabbed, with demographic, 2019–20 influenza vaccination and clinical information documented. Using logistic regression we measured the adjusted odds ratio (aOR), adjusting for study site and age, sex, calendar time, presence of chronic conditions. The main analysis included patients swabbed ≤7 days after onset from the three countries with <15% of missing influenza vaccination. In secondary analyses, we included five countries, using multiple imputation with chained equations to account for missing data. Results We included 257 COVID-19 cases and 1631 controls in the main analysis (three countries). The overall aOR between influenza vaccination and COVID-19 was 0.93 (95% CI: 0.66–1.32). The aOR was 0.92 (95% CI: 0.58–1.46) and 0.92 (95%CI: 0.51–1.67) among those aged 20–59 and ≥60 years, respectively. In secondary analyses, we included 6457 cases and 69272 controls. The imputed aOR was 0.87 (95% CI: 0.79–0.95) among all ages and any delay between swab and symptom onset. Conclusions There was no evidence that COVID-19 cases were more likely to be vaccinated against influenza than controls. Influenza vaccination should be encouraged among target groups for vaccination. I-MOVE-COVID-19 will continue documenting influenza vaccination status in 2020-21, in order to learn about effects of recent influenza vaccination.