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This report was prepared as part of the Project "Monitoring Influenza vaccine effectiveness during influenza seasons and pandemics in the European Union", financed by the European Centre for Disease Prevention and Control, and describes the results obtained in Portugal under the Protocol Agreement celebrated between EpiConcept SARL, Paris and National Health Institute Doutor Ricardo Jorge, Lisbon, signed on December 2014. ; Relatório elaborado em julho de 2015. ; [eng] Background: The EuroEVA project is the Portuguese component of the multicentre I-MOVE study. The results to be presented are related to the 7th EuroEVA season and aimed the estimation of 2014-15 end of season influenza vaccine effectiveness in i) all age groups; ii) by risk group; iii) by influenza subtype and thus contribute to monitor VE estimates every year. Material and methods: The "Protocol for case-control studies to measure seasonal influenza vaccine effectiveness in the European Union and European Economic Area Member States- Portuguese site study version" was implemented entirely with no changes to be added. VE was estimated as one minus the odds ratio of being vaccinated in cases versus controls adjusted for confounders by logistic regression. Potential confounders were investigated and included if they changed crude OR estimate in at least 10% after adjustment by the Mantel-Haenszel method. Results: In Portugal, influenza epidemic occurred between week 1/2015 and week 8/2015 and had a medium- high intensity. Both B and A(H3) virus were circulating, but with dominance of the first one. A(H1)pdm09 was only detected sporadically. From the 50 GP's that accepted to participate in the study, 31 GP's effectively participated in the study by selecting patients (which corresponds to a 62% participation rate). A total of 268 ILI patients were enrolled, each GP recruited in average 8.6 patients. After excluding 19 ILI patients the final sample for analyses consisted on 249 ILI patients (147 cases and 102 controls). From the cases, 68% were positive for type B virus, Yamagata lineage, 31% were positive for influenza A (H3) and 1% for A(H1)pdm09. Antigenic and genetic analysis indicated that influenza A(H3) viruses were genetically and antigenically different from the 2014/2015 vaccine strain, most of them belonging to the new virus cluster 3C.2a. Detected influenza B viruses belong to the same lineage (Yamagata) of the strain represented in the 2014/2015 influenza vaccine. Comparing cases and controls, we verified that they were statistically different in relation to: - Age: controls were older than cases (median age in controls was 51 yrs vs. 44 yrs in cases); - Any chronic disease: the prevalence of at least one chronic condition relevant for influenza vaccination was higher in controls (44.1% vs 28.1%); - Seasonal vaccine in 2013-14: controls were more often vaccinated against influenza in the last season than cases (28.4% vs. 12.3%); - Help bathing: controls needed more help for bathing than cases (0% in cases vs 4.1% in controls). Overall results indicated that vaccine coverage (VC) in controls was statistically higher (p<0.001) than in cases (VC controls=30.7% and VC cases=11.0%). Similar results were obtained for the target group for vaccination by the National Health Authorities (VC cases=26.8% and VC controls=54.9%, p=0.003). Restricting the analysis to type B virus (Yamagata lineage), VC was statistically (p=0.001) higher in controls than in cases (30.7% vs 8.1% in all ILI cases and 53.9% vs 20.0% in the target group). After adjustment for age, chronic disease and month of illness onset, VE adjusted estimates in all population was 63.4% (95% CI: 16.2%; 84.0%). In the target group for vaccination, after adjustment, VE estimates was 65.0% (95% CI: 8.1%; 86.7%). Restricting to B Yamagata cases, similar VE estimates were obtained for all population and target group: VE all population = 78.5% (95% CI: 39.5; 92.4); VE target group = 79.6% (95CI: 34.7; 93.6). Although all crude and adjusted VE estimates were statistically significant, low precision was observed. Conclusions: The 2014-2015 season adjusted VE estimates against B/Yamagata was approximately 79% (statistically significant but low precision). No VE estimates against A(H3) were obtained due to small sample size. All influenza B belonged to genetic group 3, different from genetic group 2, represented by B/Massachusets/02/2012 vaccine strain but antigenically these strains are related. This fact is in line with a moderate/high VE for influenza B in 2014-15 season. ; [pt] O projeto EuroEVA (Efetividade da vacina antigripal na Europa) é a componente portuguesa do estudo europeu multicêntrico I-MOVE. Os resultados apresentados correspondem à implementação do estudo EuroEVA na época 2014-2015 e pretende obter estimativas da efetividade da vacina (EV) sazonal 2014-2015 i) na população geral; ii) no grupo alvo para o qual a vacina é recomendada; iii) por tipo/sub tipo de vírus e desta forma contribuir para a monitorização da EV antigripal todas as épocas. Material e Métodos: O "Protocol for case-control studies to measure seasonal influenza vaccine effectiveness in the European Union and European Economic Area Member States- Portuguese site study version" foi implemetado na integra sem alterações a reportar. A efetividade da vacina (EV) foi estimada através de EV=1-OR sendo OR o odd ratio de estar vacinado nos casos vs controlos ajustado fatores de confundimento foram analisados e incluídos se alteraram o odds-ratio bruto em pelo menos 10% após ajustamento pelo método de Mantel Haenszel. Resultados: Em Portugal o período epidémico ocorreu entre as semanas 1/2015 e 8/2015 tendo-se verificado uma atividade gripal média-alta. Verificou-se a co circulação de vírus do tipo B e do sub-tipo A(H3), tendo o primeiro dominado durante a época. Verificou- se ainda a circulação esporádica de vírus do tipo A(H1)pdm09. De entre os 50 médicos de família (MF) que aceitaram participar no estudo, 31 reportaram doentes com síndroma gripal (SG), correspondendo a uma taxa de participação de 62%. No total foram selecionados 268 doentes com SG, em média cada médico recrutou 8,6 doentes. Após exclusão de 19, por não respeitarem a definição de caso de SG, a amostra final para análise consistia em 249 doentes com SG (147 casos positivos e 102 controlos negativos). De entre os casos, 68% eram do tipo B vírus, linhagem Yamagata, 31% eram positivos para o vírus do subtipo A (H3) e 1% para o tipo A(H1)pdm09. A análise genética e antigénica dos vírus influenza A(H3) revelou que na sua maioria pertencem ao novo grupo genético 3C.2a, que se distinguem da estirpe A(H3) contemplada na vacina da época 2014/2015. Os vírus influenza B detetados pertencem à linhagem Yamagata, à semelhança do vírus do tipo B contemplado na vacina da época 2014/2015. Comparando casos e controlos verifica-se que os grupos eram estatisticamente diferentes nas seguintes variáveis: - Idade: os controlos eram mais velhos que os casos (idade mediana nos controlos o era 51 anos vs 44 anos nos casos); - Doença crónica: a prevalência de pelo menos 1 doença crónica com relevância para a infeção por gripe era mais elevada do que controlos (44,1% vs 28,1%); - Toma da vacina na época anterior: os controlos tinham uma história passada de toma da vacina (época 2013/14) mais frequente (28,4% vs. 12,3%); - Incapacidade (Ajuda na toma de banho): os controlos manifestaram em maior percentagem necessidade de ajuda para tomar banho (0% nos casos vs 4,1% nos controlos) De uma forma geral, a cobertura da vacina (CV) sazonal antigripal 2014/15 foi mais elevada (e com significado estatístico, p<0.001) nos controlos (30,7%) do que nos casos (CV=11,0%). Restringindo a análise para o grupo alvo para a toma da vacina de acordo com as Autoridades de Saúde Nacionais, verificaram-se resultados semelhantes (CV casos=26,8% and CV controlos=54,9%, p=0,003). Relativamente à análise por tipo de vírus dominante (vírus do tipo B/ Yamagata), a CV era estatisticamente superior (p=0,001) nos controlos do que nos casos (30,7% vs 8,1% na população geral e 53,9% vs 20,0% no grupo alvo da vacina). Após ajustamento para idade, presença de doença crónica e mês de início de sintomas, a EV ajustada para a população em geral foi de 63,4% (IC95%: 16,2%-84,0%). No grupo alvo da vacina a estimativa ajustada situa a EV em 65,0% (IC95%: 8,1%-86,7%). Restringindo a análise aos casos B/ Yamagata, obtiveram-se valores similares na população em geral e no grupo alvo da vacina: EV população geral = 78,5% (IC95%: 39,5%-92,4%); EV grupo alvo = 79.6% (IC95%: 34,7%-93,6%). Embora ambas as estimativas tenham significado estatístico, a precisão é baixa. ; European Center for disease Prevention and Control

Letters to editor ; This study aimed to provide early 2017/2018 seasonal IVE using data from the Portuguese influenza surveillance system. This analysis included patients with influenza-like illness (ILI) from primary care and emergency departments swabbed for the detection of influenza using RT-PCR between weeks 38/2017 to 5/2018. We used the test-negative case–control study design, where influenza laboratory confirmed incident ILI patients (Cases) were compared to laboratory influenza negative ILI patients (Controls). IVE analysis was restricted to ILI patients with symptoms compatible with the European Union ILI definition, i.e., with sudden onset of at least one systemic and one respiratory symptom. Chi-square test was used to compare baseline characteristics between Cases and Controls. Crude IVE, design adjusted for calendar time, was estimated using 1-odds ratio (OR) of being vaccinated in Cases vs. Controls and was further adjusted for confounding by age group and presence of chronic condition.A total of 732 ILI patients were reported to the NISS and approximately 74% adhered to the ILI definition. In a season with B/Yamagata dominance and with vaccine lineage mismatch, the 2017/2018 trivalent seasonal influenza vaccine conferred moderate protection against medically attended influenza. The use of surveillance data constituted a useful tool to have early in the season IVE estimates. These results assist modifications to health interventions, such as using antiviral treatment in high-risk patients, reinforcement of social eviction and individual hygiene measures to reduce risk of influenza transmission, regardless of the vaccination status. ; info:eu-repo/semantics/publishedVersion

Regarding the wide genetic and antigenic variability of influenza viruses, overall or subtype influenza vaccine effectiveness (IVE) estimates may not be sufficient to assess vaccine protection against circulating strains. This is particularly important when low VE against a specific clade is suspicious or a new drifted virus is emerging. Viral genetic characterization is routinely performed in influenza surveillance but viruses are selected according patient age, severity and vaccine status. For instance, last season genetic characterized cases were more vaccinated than those not selected. A protocol for virological data integration on IVE studies within I-MOVE network was performed. It intended to solve the following issues: 1. Selection of the clade of interest to provide IVE; 2. Determination of the number of cases needed for genetic characterization; 3. Selection of cases for genetic characterization independently of patient features. During the 2015/16 season, a closely contact between epidemiological and laboratorial teams allows to perform a random selection of influenza cases for genetic characterization independently of cases features. Influenza A(H1N1)pdm09 was the selected subtype given its predominance and the emergence of new subclades (6B.1 and 6B.2). 52.2% of A(H1)pdm09 cases were successfully characterized. No differences regarding age, sex and vaccine status were found between selected and unselected cases for genetic characterization. The large sample size needed to estimate IVE against a specific clade requires an important effort on genetic characterization behind virological surveillance. However, random selection of cases for genetic characterization along season seems to be feasible without interfering with virological surveillance and obtains a representative sample of cases of the clade of interest. Virological data from randomly selected cases will permit to estimate IVE against a specific clade during influenza season. An extra effort on influenza genetic characterization is needed to achieve the needed sample size. ; This project was financed by the European Center for Disease Prevention and Control for data and actvi;es related to the individuals with less then 65 years. Data and activities related to the individuals 65 years and more were funded by European Union's Horizon 2020 research and innova;on programme under grant agreement No 634446. ; N/A

Background: Well-established influenza surveillance systems (ISS) can be used for respiratory syncytial virus (RSV) surveillance. In Portugal, RSV cases are detected through the ISS using the European Union (EU) influenza-like illness (ILI) case definition. Aim: To investigate clinical predictors for RSV infection and how three case definitions (EU ILI, a modified EU acute respiratory infection, and one respiratory symptom) performed in detecting RSV infections in Portugal. Methods: This observational retrospective study used epidemiological and laboratory surveillance data (October 2010–May 2018). Associations between clinical characteristics and RSV detection were analysed using logistic regression. Accuracy of case definitions was assessed through sensitivity, specificity, and area under the receiver operating characteristic curve (AUC). A 0.05 significance level was accepted. Results: The study involved 6,523 persons, including 190 (2.9%) RSV cases. Among 183 cases with age information, RSV infection was significantly more frequent among individuals < 5 years (n = 23; 12.6%) and ≥ 65 years (n = 45; 24.6%) compared with other age groups (p < 0.0001). Cough (odds ratio (OR): 2.4; 95% confidence interval (CI): 1.2–6.5) was the best RSV-infection predictor considering all age groups, while shortness of breath was particularly associated with RSV-positivity among ≤ 14 year olds (OR: 6.7; 95% CI: 2.6–17.4 for 0–4 year olds and OR: 6.7; 95% CI: 1.5–28.8 for 5–14 year olds). Systemic symptoms were significantly associated with RSV-negative and influenza-positive cases. None of the case definitions were suitable to detect RSV infections (AUC = 0.51). Conclusion: To avoid underestimating the RSV disease burden, RSV surveillance within the Portuguese sentinel ISS would require a more sensitive case definition than ILI and, even a different case definition according to age. ; info:eu-repo/semantics/publishedVersion

BACKGROUND: Well-established influenza surveillance systems (ISS) can be used for respiratory syncytial virus (RSV) surveillance. In Portugal, RSV cases are detected through the ISS using the European Union (EU) influenza-like illness (ILI) case definition. AIM: To investigate clinical predictors for RSV infection and how three case definitions (EU ILI, a modified EU acute respiratory infection, and one respiratory symptom) performed in detecting RSV infections in Portugal. METHODS: This observational retrospective study used epidemiological and laboratory surveillance data (October 2010–May 2018). Associations between clinical characteristics and RSV detection were analysed using logistic regression. Accuracy of case definitions was assessed through sensitivity, specificity, and area under the receiver operating characteristic curve (AUC). A 0.05 significance level was accepted. RESULTS: The study involved 6,523 persons, including 190 (2.9%) RSV cases. Among 183 cases with age information, RSV infection was significantly more frequent among individuals < 5 years (n = 23; 12.6%) and ≥ 65 years (n = 45; 24.6%) compared with other age groups (p < 0.0001). Cough (odds ratio (OR): 2.4; 95% confidence interval (CI): 1.2–6.5) was the best RSV-infection predictor considering all age groups, while shortness of breath was particularly associated with RSV-positivity among ≤ 14 year olds (OR: 6.7; 95% CI: 2.6–17.4 for 0–4 year olds and OR: 6.7; 95% CI: 1.5–28.8 for 5–14 year olds). Systemic symptoms were significantly associated with RSV-negative and influenza-positive cases. None of the case definitions were suitable to detect RSV infections (AUC = 0.51). CONCLUSION: To avoid underestimating the RSV disease burden, RSV surveillance within the Portuguese sentinel ISS would require a more sensitive case definition than ILI and, even a different case definition according to age.

This report was prepared as part of the Project "Monitoring Influenza vaccine effectiveness during influenza seasons and pandemics in the European Union" and describes the results obtained in Portugal under the Protocol Agreement celebrated between EpiConcept SARL, Paris and National Health Institute Dr. Ricardo Jorge, Lisbon. Data and activities related to the individuals 65 years and more were funded by European Union's Horizon 2020 research and innovation programme under grant agreement no 634446. ; The results to be presented are related to the 8th EuroEVA season (the Portuguese component of the multicentre I-MOVE study) and aimed the estimation of 2015/2016 end of season influenza vaccine effectiveness in i) all age groups and in <65 and 65 plus years ; ii) by risk group; iii) by influenza subtype and clade. Material and methods: The "Protocol for case-control studies to measure seasonal influenza vaccine effectiveness in the European Union and European Economic Area Member States- Portuguese site study version" was implemented entirely adding a new variable related to statin uptake. Also, a pilot study to incorporate genetic characterization of influenza virus from patients enrolled in vaccine effectiveness (VE) study was implemented. Within this pilot study, influenza A(H1)pdm09 positive cases were randomly selected to be genetically characterized. Selection was conducted in three phases of the epidemic: early, peak and late season. Results: In Portugal, a low intensity influenza epidemic occurred between week 53/2015 and week 8/2016. Influenza A(H1)pdm09 virus predominated during all season. Influenza B/Victoria lineage was detected in co-circulation in late season. From the 84 GP's that accepted to participate in the study, 51 GP's effectively participated in the study selecting patients (60.7% participation rate). A total of 336 ILI patients were enrolled and after excluding 26 ILI patients the final sample for analyses consisted on 310 ILI patients (147 cases and 102 controls). From the cases, 89.5% were positive for influenza A(H1)pdm09, 8.9% were positive for influenza B/Victoria and the remaining (1.6%) were positive for influenza A(H3). For genetic characterization of influenza virus, A(H1)pdm09 virus subtype was selected. The HA1 subunit of the hemaglutinin gene were successfully sequenced for 93 out of 126 cases with detected viruses. Phylogenetic analysis and clade assignment were performed. The majority of A(H1)pdm09 viruses belonged to the subgroup 6B.1 (87.1%) and the remaining viruses belonged to 6B clade. Comparing cases and controls, was confirmed that they were statistically different in relation to time between onset and swab collection, sex, seasonal vaccine uptake in 2014/2015, presence of at least one chronic disease and number of GP consultations in last 12 months. For 2015/2016 trivalent influenza vaccine, confounder- adjusted VE against A(H1)pdm09 was 54.0% (95% CI: -1.5; 79.2%) in all population and 63.9% (95% CI: (7.7%; 85.9%) in the target group for vaccination. Considering the population with less than 65 years, VE against AH1pdm09 was 56.2% (95% CI: -17.5%; 83.7%) and 74.9% (95% CI: -37.1; 95.4%) in the and more years of age. Conclusions: VE estimates during 2015/2016 season indicated that the seasonal flu vaccine conferred moderate protection against A(H1)pdm09 (varied between 54% to 64% considering all population and the target group for vaccination). The vaccine had a better performance in the elderly, where VE point estimates reached 75% (not significant nevertheless). The implementation of the genetic characterization pilot study was well succeeded, with a success rate of influenza virus characterization of 80.2%. For future seasons, the high sampling fraction in the first phase should continue in order to assist the definition of the virus subtype/clade target during the season. ; Os resultados apresentados correspondem à implementação da 8ª época do EuroEVA (a componente portuguesa do estudo multicêntrico I-MOVE) e pretende obter estimativas da efetividade da vacina (EV) sazonal 2015/2016 i) em todos os grupos etários e no grupo com idade inferior a 65 e com 65 e mais anos; ii) por grupo-alvo da vacinação e iii) por subtipo de vírus da gripe e por clade. Material e métodos: O "Protocol for case-control studies to measure seasonal influenza vaccine effectiveness in the European Union and European Economic Area Member States- Portuguese site study version" foi implementado na íntegra, acrescentando um nova variável relacionada com a toma de estatinas. De igual modo, foi implementando um estudo-piloto relacionado com a incorporação da caracterização genética dos participantes no estudo da efetividade. Dentro deste estudo-piloto, os casos positivos de A(H1)pdm09 foram aleatoriamente selecionados para caracterização genética, seleção esta que foi conduzida nas três fases do período epidémico: início, pico e fim. Resultados: Em Portugal o período epidémico ocorreu entre as semanas 53/2015 e 8/2016 tendo-se verificado uma atividade gripal de intensidade baixa. Predominou a circulação de vírus do subtipo Influenza A(H1)pdm09 e o vírus Influenza da linhagem B/Victoria co-circulou no final da época. De entre os 84 médicos de família (MF) que aceitaram participar no estudo, 51 reportaram doentes com síndroma gripal (SG), correspondendo a uma taxa de participação de 60,7%. No total foram selecionados 336 doentes com SG. Após exclusão de 26 doentes, a amostra final consistiu em 310 doentes com SG (147 casos e 102 controlos). De entre os casos, 89,5% eram do subtipo A(H1)pdm2009, 8,9% eram positivos para o vírus do subtipo B/Victoria e os restantes (1,6%) para o tipo A(H3). Para efeito de caracterização genética, o subptipo A(H1)pdm09 foi selecionado. A subunidade HA1 do gene da hemaglutinina foi sequenciada com sucesso para 93 dos 126 casos. A maioria dos casos de A(H1)pdm09 pertencia ao subgrupo 6B.1 (87,1%) e os restantes ao subgrupo 6B. Comparando casos e controlos verifica-se que os grupos eram estatisticamente diferentes no que diz respeito, ao tempo entre início de sintomas e colheita, ao sexo, a toma da vacina na época anterior, à presença de doença crónica relevante para vacinação da gripe e ao número de consultas com o MF nos últimos 12 meses. Para a vacina trivalente antigripal 2015/2016 a EV ajustada para confundimento contra o subtipo A(H1)pdm09 foi 54,0% (IC95%: -1,5; 79,2%) na população em geral e 63,9% (IC95%: (7,7%; 85,9%) no grupo alvo da vacinação contra a gripe. Considerando a população com menos de 65 anos, a EV contra o subtipo A(H1)pdm09 foi de 56,2 % (IC 95%: -17,5%; 83,7%), sendo que foi de 74,9% (IC 95%: -37,1; 95,4%) no grupo com 65 e mais anos de idade. Conclusões: As estimativas da EV da época 2015/2016 indicam que a vacina conferiu proteção moderada contra o subtipo A(H1)pdm09 (variou entre 54% e 64%, para a população em geral e para o grupo alvo da vacina, respetivamente). A vacina parece demonstrar uma melhor performance na população mais idosa, onde as estimativas da EV alcançam os 75% (apesar de não estatisticamente significativas). A implementação do estudo piloto foi bem conseguida, com uma taxa de sucesso de caracterização genética de 80,2%. Em épocas futuras, a amostragem na primeira fase deve manter elevada, de modo a assistir à definição do subtipo/clade do vírus a ser caracterizado.

O Departamento de Epidemiologia em conjunto com o Departamento de Doenças Infecciosas do INSA realizaram um estudo, na época de 2009-2010, que teve por objectivo estimar a efectividade da vacina sazonal (em indivíduos com 65 e mais anos) e pandémica (todas as idades). O estudo contou com a participação de: Portugal, Espanha, Irlanda, França, Itália, Hungria e Roménia. Este estudo surge enquadrado no projecto europeu multicêntrico - I-MOVE- Monitoring influenza vaccine efectiveness during influenza seasons and pandemics in the European Union, coordenado pela EpiConcept SARL e financiado pelo ECDC, que pretende estimar a efectividade da vacina sazonal e pandémica durante e após a época de gripe.

Influenza antigenic and genetic characterisation data are crucial for influenza vaccine composition decision making. Previously, aggregate data were reported to the European Centre for Disease Prevention and Control by European Union/European Economic Area (EU/EEA) countries. A system for collecting case-specific influenza antigenic and genetic characterisation data was established for the 2013/14 influenza season. In a pilot study, 11 EU/EEA countries reported through the new mechanism. We demonstrated feasibility of reporting strain-based antigenic and genetic data and ca 10% of influenza virus-positive specimens were selected for further characterisation. Proportions of characterised virus (sub)types were similar to influenza virus circulation levels. The main genetic clades were represented by A/StPetersburg/27/2011(H1N1)pdm09 and A/Texas/50/2012(H3N2). A(H1N1)pdm09 viruses were more prevalent in age groups (by years) < 1 (65%; p = 0.0111), 20-39 (50%; p = 0.0046) and 40-64 (55%; p = 0.00001) while A(H3N2) viruses were most prevalent in those ≥ 65 years (62%*; p = 0.0012). Hospitalised patients in the age groups 6-19 years (67%; p = 0.0494) and ≥ 65 years (52%; p = 0.0005) were more frequently infected by A/Texas/50/2012 A(H3N2)-like viruses compared with hospitalised cases in other age groups. Strain-based reporting enabled deeper understanding of influenza virus circulation among hospitalised patients and substantially improved the reporting of virus characterisation data. Therefore, strain-based reporting of readily available data is recommended to all reporting countries within the EU/EEA. ; Sí

Within the Influenza Monitoring Vaccine Effectiveness in Europe (I-MOVE) project we conducted a multicentre case–control study in eight European Union (EU) Member States to estimate the 2011/12 influenza vaccine effectiveness against medically attended influenza-like illness (ILI) laboratory-confirmed as influenza A(H3) among the vaccination target groups. Practitioners systematically selected ILI / acute respiratory infection patients to swab within seven days of symptom onset. We restricted the study population to those meeting the EU ILI case definition and compared influenza A(H3) positive to influenza laboratory-negative patients. We used logistic regression with study site as fixed effect and calculated adjusted influenza vaccine effectiveness (IVE), controlling for potential confounders (age group, sex, month of symptom onset, chronic diseases and related hospitalisations, number of practitioner visits in the previous year). Adjusted IVE was 25% (95% confidence intervals (CI): -6 to 47) among all ages (n=1,014), 63% (95% CI: 26 to 82) in adults aged between 15 and 59 years and 15% (95% CI: -33 to 46) among those aged 60 years and above. Adjusted IVE was 38% (95%CI: -8 to 65) in the early influenza season (up to week 6 of 2012) and -1% (95% CI: -60 to 37) in the late phase. The results suggested a low adjusted IVE in 2011/12. The lower IVE in the late season could be due to virus changes through the season or waning immunity. Virological surveillance should be enhanced to quantify change over time and understand its relation with duration of immunological protection. Seasonal influenza vaccines should be improved to achieve acceptable levels of protection. ; ECDC

Respiratory syncytial virus (RSV) is a common cause of acute lower respiratory tract infections and hospitalisations among young children and is globally responsible for many deaths in young children, especially in infants aged <6 months. Furthermore, RSV is a common cause of severe respiratory disease and hospitalisation among older adults. The development of new candidate vaccines and monoclonal antibodies highlights the need for reliable surveillance of RSV. In the European Union (EU), no up-to-date general recommendations on RSV surveillance are currently available. Based on outcomes of a workshop with 29 European experts in the field of RSV virology, epidemiology and public health, we provide recommendations for developing a feasible and sustainable national surveillance strategy for RSV that will enable harmonisation and data comparison at the European level. We discuss three surveillance components: active sentinel community surveillance, active sentinel hospital surveillance and passive laboratory surveillance, using the EU acute respiratory infection and World Health Organization (WHO) extended severe acute respiratory infection case definitions. Furthermore, we recommend the use of quantitative reverse transcriptase PCR-based assays as the standard detection method for RSV and virus genetic characterisation, if possible, to monitor genetic evolution. These guidelines provide a basis for good quality, feasible and affordable surveillance of RSV. Harmonisation of surveillance standards at the European and global level will contribute to the wider availability of national level RSV surveillance data for regional and global analysis, and for estimation of RSV burden and the impact of future immunisation programmes.

Free PMC article: https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/32258201/ ; Background: Morbidity, severity, and mortality associated with annual influenza epidemics are of public health concern. We analyzed surveillance data on hospitalized laboratory-confirmed influenza cases admitted to intensive care units to identify common determinants for fatal outcome and inform and target public health prevention strategies, including risk communication. Methods: We performed a descriptive analysis and used Poisson regression models with robust variance to estimate the association of age, sex, virus (sub)type, and underlying medical condition with fatal outcome using European Union data from 2009 to 2017. Results: Of 13 368 cases included in the basic dataset, 2806 (21%) were fatal. Age ≥40 years and infection with influenza A virus were associated with fatal outcome. Of 5886 cases with known underlying medical conditions and virus A subtype included in a more detailed analysis, 1349 (23%) were fatal. Influenza virus A(H1N1)pdm09 or A(H3N2) infection, age ≥60 years, cancer, human immunodeficiency virus infection and/or other immune deficiency, and heart, kidney, and liver disease were associated with fatal outcome; the risk of death was lower for patients with chronic lung disease and for pregnant women. Conclusions: This study re-emphasises the importance of preventing influenza in the elderly and tailoring strategies to risk groups with underlying medical conditions. ; info:eu-repo/semantics/publishedVersion

Background: Morbidity, severity, and mortality associated with annual influenza epidemics are of public health concern. We analyzed surveillance data on hospitalized laboratory-confirmed influenza cases admitted to intensive care units to identify common determinants for fatal outcome and inform and target public health prevention strategies, including risk communication. Methods: We performed a descriptive analysis and used Poisson regression models with robust variance to estimate the association of age, sex, virus (sub)type, and underlying medical condition with fatal outcome using European Union data from 2009 to 2017. Results: Of 13 368 cases included in the basic dataset, 2806 (21%) were fatal. Age ≥40 years and infection with influenza A virus were associated with fatal outcome. Of 5886 cases with known underlying medical conditions and virus A subtype included in a more detailed analysis, 1349 (23%) were fatal. Influenza virus A(H1N1)pdm09 or A(H3N2) infection, age ≥60 years, cancer, human immunodeficiency virus infection and/or other immune deficiency, and heart, kidney, and liver disease were associated with fatal outcome; the risk of death was lower for patients with chronic lung disease and for pregnant women. Conclusions: This study re-emphasises the importance of preventing influenza in the elderly and tailoring strategies to risk groups with underlying medical conditions. ; This work was funded by an internal ECDC budget. ; Sí

BACKGROUND: Morbidity, severity, and mortality associated with annual influenza epidemics are of public health concern. We analyzed surveillance data on hospitalized laboratory-confirmed influenza cases admitted to intensive care units to identify common determinants for fatal outcome and inform and target public health prevention strategies, including risk communication. METHODS: We performed a descriptive analysis and used Poisson regression models with robust variance to estimate the association of age, sex, virus (sub)type, and underlying medical condition with fatal outcome using European Union data from 2009 to 2017. RESULTS: Of 13 368 cases included in the basic dataset, 2806 (21%) were fatal. Age ≥40 years and infection with influenza A virus were associated with fatal outcome. Of 5886 cases with known underlying medical conditions and virus A subtype included in a more detailed analysis, 1349 (23%) were fatal. Influenza virus A(H1N1)pdm09 or A(H3N2) infection, age ≥60 years, cancer, human immunodeficiency virus infection and/or other immune deficiency, and heart, kidney, and liver disease were associated with fatal outcome; the risk of death was lower for patients with chronic lung disease and for pregnant women. CONCLUSIONS: This study re-emphasises the importance of preventing influenza in the elderly and tailoring strategies to risk groups with underlying medical conditions.

Influenza A(H3N2) viruses predominated in Europe in 2016-17. In 2017-18 A(H3N2) and A(H1N1)pdm09 viruses co-circulated. The A(H3N2) vaccine component was the same in both seasons; while the A(H1N1)pdm09 component changed in 2017-18. In both seasons, vaccine seed A(H3N2) viruses developed adaptations/alterations during propagation in eggs, impacting antigenicity. We used the test-negative design in a multicentre primary care case-control study in 12 European countries to measure 2016-17 and 2017-18 influenza vaccine effectiveness (VE) against laboratory-confirmed influenza A(H1N1)pdm09 and A(H3N2) overall and by age group. During the 2017-18 season, the overall VE against influenza A(H1N1)pdm09 was 59% (95% CI: 47-69). Among those aged 0-14, 15-64 and ≥65 years, VE against A(H1N1)pdm09 was 64% (95% CI: 37-79), 50% (95% CI: 28-66) and 66% (95% CI: 42-80), respectively. Overall VE against influenza A(H3N2) was 28% (95% CI: 17-38) in 2016-17 and 13% (95% CI: -15 to 34) in 2017-18. Among 0-14-year-olds VE against A(H3N2) was 28% (95%CI: -10 to 53) and 29% (95% CI: -87 to 73), among 15-64-year-olds 34% (95% CI: 18-46) and 33% (95% CI: -3 to 56) and among those aged ≥65 years 15% (95% CI: -10 to 34) and -9% (95% CI: -74 to 32) in 2016-17 and 2017-18, respectively. Our study suggests the new A(H1N1)pdm09 vaccine component conferred good protection against circulating strains, while VE against A(H3N2) was <35% in 2016-17 and 2017-18. The egg propagation derived antigenic mismatch of the vaccine seed virus with circulating strains may have contributed to this low effectiveness. A(H3N2) seed viruses for vaccines in subsequent seasons may be subject to the same adaptations; in years with lower than expected VE, recommendations of preventive measures other than vaccination should be given in a timely manner. ; This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement no. 634446 to conduct the study in individuals aged 65 years or more. ECDC has contributed funds for the coordination and some study sites under the Framework contract no. ECDC/2014/026 for the individuals aged less than 65 years. The WHO Regional office for Europe has contributed funds for the Romanian study site. ; Sí