2015/16 seasonal vaccine effectiveness against hospitalisation with influenza a(H1N1)pdm09 and B among elderly people in Europe: Results from the I-MOVE+ project

We conducted a multicentre test-negative caseâ\u80\u93control study in 27 hospitals of 11 European countries to measure 2015/16 influenza vaccine effectiveness (IVE) against hospitalised influenza A(H1N1)pdm09 and B among people aged â\u89¥ 65 years. Patients swabbed within 7 days after onset of symptoms compatible with severe acute respiratory infection were included. Information on demographics, vaccination and underlying conditions was collected. Using logistic regression, we measured IVE adjusted for potential confounders. We included 355 influenza A(H1N1)pdm09 cases, 110 influenza B cases, and 1,274 controls. Adjusted IVE against influenza A(H1N1)pdm09 was 42% (95% confidence interval (CI): 22 to 57). It was 59% (95% CI: 23 to 78), 48% (95% CI: 5 to 71), 43% (95% CI: 8 to 65) and 39% (95% CI: 7 to 60) in patients with diabetes mellitus, cancer, lung and heart disease, respectively. Adjusted IVE against influenza B was 52% (95% CI: 24 to 70). It was 62% (95% CI: 5 to 85), 60% (95% CI: 18 to 80) and 36% (95% CI: -23 to 67) in patients with diabetes mellitus, lung and heart disease, respectively. 2015/16 IVE estimates against hospitalised influenza in elderly people was moderate against influenza A(H1N1)pdm09 and B, including among those with diabetes mellitus, cancer, lung or heart diseases

The influenza season 2016/17 in Bucharest, Romania – surveillance data and clinical characteristics of patients with influenza-like illness admitted to a tertiary infectious diseases hospital

ABSTRACT Background: Influenza continues to drive seasonal morbidity, particularly in settings with low vaccine coverage. Objectives: To describe the influenza cases and viral circulation among hospitalized patients. Methods: A prospective study based on active surveillance of inpatients with influenza-like illness from a tertiary hospital in Bucharest, Romania, in the season 2016/17. Results: A total of 446 patients were tested, with a balanced gender distribution. Overall, 192 (43%) patients tested positive for influenza, with the highest positivity rate in the age groups 3–13 years and >65 years. Peak activity occurred between weeks 1 and 16/2017, with biphasic distribution: A viruses were replaced by B viruses from week 9/2017; B viruses predominated (66.1%). Among the 133 (69.3%) subtyped samples, all influenza A were subtype H3 (n = 57) and all influenza B were B/Victoria (n = 76). Patients who tested positive for influenza presented fewer comorbidities (p = 0.012), except for the elderly, in whom influenza was more common in patients with comorbidities (p = 0.050). Disease evolution was generally favorable under antiviral treatment. The length of hospital stay was slightly longer in patients with influenza-like illness who tested patients negative for influenza (p = 0.031). Conclusions: Distinctive co-circulation of A/H3 and B/Victoria in Bucharest, Romania in the 2016/17 influenza season was found. While the A/H3 subtype was predominant throughout Europe that season, B/Victoria appears to have circulated specifically in Romania and the Eastern European region, predominantly affecting preschoolers and school children