Cornelia Adlhoch

Over the last decade, bacterial sexually transmitted infection notifications have increased across the European Union/European Economic Area (EU/EEA) and England. However, six EU/EEA countries — Denmark, Finland, Ireland, the Netherlands, Norway and Sweden — and England, reported declines in chlamydia notifications from 2023 to 2024. To explore potential drivers of these decreases, the European Centre for Disease Prevention and Control, together with experts from the seven countries, analysed national surveillance data from 2015 to 2024 and contextualised findings with information on testing practices, policies and public health interventions. Chlamydia notifications in 2024 were compared with expected counts based on trends before the COVID-19 pandemic (2015–2019) using a negative binomial model. Across countries, decreases between 2023 and 2024 ranged from 13% to 19%, primarily affecting 15–24-year-olds. Case numbers fell below the 95% prediction interval in three countries. Five countries reported reduced testing volumes among young people, and all observed lower positivity rates. Some countries implemented online testing and targeted sexual health promotion campaigns. Although reduced testing, changes in behaviour during the COVID-19 pandemic and the risk profile of those accessing testing may have contributed to the declines, further investigation into underlying drivers is necessary to inform sexual health strategies in Europe.

This position paper addresses the evolving care continuum for patients with respiratory viral infections in the context of the post–coronavirus disease 2019 pandemic phase. We emphasize the need to place the patient at the center of attention from the first signs of influenza-like illness to recovery. Current practices have revealed several deficiencies, such as timely access to healthcare, fragmentation of care, and inadequate follow-up instructions. This article proposes means to address these deficiencies and discusses diagnostic and management considerations for patients with suspected influenza infection.

Since 2016, A(H5Nx) high pathogenic avian influenza (HPAI) virus of clade 2.3.4.4b has become one of the most serious global threats not only to wild and domestic birds, but also to public health. In recent years, important changes in the ecology, epidemiology, and evolution of this virus have been reported, with an unprecedented global diffusion and variety of affected birds and mammalian species. After the two consecutive and devastating epidemic waves in Europe in 2020–2021 and 2021–2022, with the second one recognized as one of the largest epidemics recorded so far, this clade has begun to circulate endemically in European wild bird populations. This study used the complete genomes of 1,956 European HPAI A(H5Nx) viruses to investigate the virus evolution during this varying epidemiological outline. We investigated the spatiotemporal patterns of A(H5Nx) virus diffusion to/from and within Europe during the 2020–2021 and 2021–2022 epidemic waves, providing evidence of ongoing changes in transmission dynamics and disease epidemiology. We demonstrated the high genetic diversity of the circulating viruses, which have undergone frequent reassortment events, providing for the first time a complete overview and a proposed nomenclature of the multiple genotypes circulating in Europe in 2020–2022. We described the emergence of a new genotype with gull adapted genes, which offered the virus the opportunity to occupy new ecological niches, driving the disease endemicity in the European wild bird population. The high propensity of the virus for reassortment, its jumps to a progressively wider number of host species, including mammals, and the rapid acquisition of adaptive mutations make the trend of virus evolution and spread difficult to predict in this unfailing evolving scenario.

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Background: Timely treatment with neuraminidase inhibitors (NAI) can reduce severe outcomes in influenza patients. Aim: We assessed the impact of antiviral treatment on in-hospital deaths of laboratory-confirmed influenza patients in 11 European Union countries from 2010/11 to 2019/20. Methods: Case-based surveillance data from hospitalised patients with known age, sex, outcome, ward, vaccination status, timing of antiviral treatment, and hospitalisation were obtained. A mixed effect logistic regression model using country as random intercept was applied to estimate the adjusted odds ratio (aOR) for in-hospital death in patients treated with NAIs vs not treated. Results: Of 19,937 patients, 31% received NAIs within 48 hours of hospital admission. Older age (60–79 years aOR 3.0, 95% CI: 2.4–3.8; 80 years 8.3 (6.6–10.5)) and intensive care unit admission (3.8, 95% CI: 3.4–4.2) increased risk of dying, while early hospital admission after symptom onset decreased risk (aOR 0.91, 95% CI: 0.90–0.93). NAI treatment initiation within 48 hours and up to 7 days reduced risk of dying (0–48 hours aOR 0.51, 95% CI: 0.45–0.59; 3–4 days 0.59 (0.51–0.67); 5–7 days 0.64 (0.56–0.74)), in particular in patients 40 years and older (e.g. treatment within 48 hours: 40–59 years aOR 0.43, 95% CI: 0.28–0.66; 60–79 years 0.50 (0.39–0.63); ≥80 years 0.51 (0.42–0.63)). Conclusion: NAI treatment given within 48 hours and possibly up to 7 days after symptom onset reduced risk of in-hospital death. NAI treatment should be considered in older patients to prevent severe outcomes.

In the WHO European Region, COVID-19 non-pharmaceutical interventions continued slowing influenza circulation in the 2021/22 season, with reduced characterisation data. A(H3) predominated and, in some countries, co-circulated with A(H1)pdm09 and B/Victoria viruses. No B/Yamagata virus detections were confirmed. Substantial proportions of characterised circulating virus subtypes or lineages differed antigenically from their respective northern hemisphere vaccine components. Appropriate levels of influenza virus characterisations should be maintained until the season end and in future seasons, when surveillance is adapted to integrate SARS-CoV-2.

Background: Research indicates that timely treatment with neuraminidase inhibitors (NAI) reduces severe outcomes in influenza-infected patients. Our aim was to analyse case-based data on NAI treatment in hospitalised laboratory-confirmed influenza patients in EU countries from 2010/11 to 2019/20 to assess this. Methods: Propensity weighted adjusted robust Poisson regression models were used to estimate the incidence rate ratio (IRR) for in-hospital death in patients treated with NAIs versus not treated, adjusted for age, sex, virus (sub)type, timing of hospitalisation and treatment, hospital unit, and spatial clustering Findings: NAI were mostly (83%) given within two days after hospital admission. Our results support the role of early treatment within 48 hours (incidence risk ration (IRR) 0·63; 95% confidence interval (CI) 0·56-0·70), even administered later than 48 hours and up to seven days, to reduce the risk of in-hospital death. Older age and intensive care unit admission (IRR 2·69; 95%CI 2·49-2·91) increased the risk of dying, while early hospital admission after onset of symptoms decreased the risk (IRR 0·94; 95%CI 0·92-0·95). Age-stratified analysis showed that NAI treatment reduced the risk in people 40 years and older. Among hospitalised patients with underlying conditions and clinical complications, antiviral treatment reduced risk to die when given within 48 hours after onset of symptoms compared to later (IRR 0·79; 95%CI 0·66-0·94). Interpretation: NAI treatment given up to seven days after symptom onset reduced the risk of in-hospital death. NAI treatment should be considered particularly in age-group ≥ 40 to prevent severe outcomes. Funding Information: Internal funds of ECDC. Declaration of Interests: None declared. Ethics Approval Statement: Not required.

Background: Annual seasonal influenza activity in the northern hemisphere causes a high burden of disease during the winter months, peaking in the first weeks of the year. Aim: We describe the 2019/20 influenza season and the impact of the COVID-19 pandemic on sentinel surveillance in the World Health Organization (WHO) European Region. Methods: We analysed weekly epidemiological and virological influenza data from sentinel primary care and hospital sources reported by countries, territories and areas (hereafter countries) in the European Region. Results: We observed co-circulation of influenza B/Victoria-lineage, A(H1)pdm09 and A(H3) viruses during the 2019/20 season, with different dominance patterns observed across the Region. A higher proportion of patients with influenza A virus infection than type B were observed. The influenza activity started in week 47/2019, and influenza positivity rate was ≥ 50% for 2 weeks (05–06/2020) rather than 5–8 weeks in the previous five seasons. In many countries a rapid reduction in sentinel reports and the highest influenza activity was observed in weeks 09–13/2020. Reporting was reduced from week 14/2020 across the Region coincident with the onset of widespread circulation of SARS-CoV-2. Conclusions: Overall, influenza type A viruses dominated; however, there were varying patterns across the Region, with dominance of B/Victoria-lineage viruses in a few countries. The COVID-19 pandemic contributed to an earlier end of the influenza season and reduced influenza virus circulation probably owing to restricted healthcare access and public health measures.