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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.

Introduction Influenza vaccination is recommended to pregnant women in Spain to reduce the risk of influenza-related complications. Influenza related hospitalizations pose a significant disease burden in children every year. Although children below 6 months are too young to be vaccinated, they can receive protection against influenza through vaccination of their mothers during pregnancy. We estimated the effectiveness of maternal influenza vaccination to prevent influenza hospitalizations in infants under 6 months of age. Methods This is a retrospective pilot study, using data from the Severe Hospitalized Confirmed Influenza Cases (SHCIC) surveillance system in seasons 2017/18 and 2018/19 in Spain. Maternal vaccination status during pregnancy was collected for cases in children 6 months and younger hospitalized with confirmed influenza infection. Influenza vaccine effectiveness was estimated using the screening method, by comparing the proportion of children with vaccinated mothers during pregnancy (proportion of cases vaccinated, PCV), with the vaccination coverage among pregnant women in Spain (proportion of population vaccinated, PPV). Results For all the study period, the PCV was 17% and the PPV was 35%. Influenza vaccination in mothers during pregnancy prevented influenza confirmed hospitalizations in infants aged 6 months and younger with a 61% (95%CI: 27–79%) effectiveness. Conclusions In line with evidence from other countries, influenza vaccination during pregnancy protects infants up to 6 months of age from influenza hospitalizations in Spain. These results support current recommendations of influenza vaccination in pregnant women, and more studies are needed in Spain to confirm the double protection of maternal vaccination in mothers and infants.

Single-dose vaccination was widely recommended in the pre-Omicron era for persons with previous SARS-CoV-2 infection. The effectiveness of a second vaccine dose in this group in the Omicron era is unknown.We linked nationwide population registries in Spain to identify community-dwelling individuals aged 18-64, with a positive SARS-CoV-2 test before single-dose mRNA vaccination (mRNA-1273 or BNT162b2). Every day between January 3 and February 6, 2022 we matched 1:1 individuals receiving a second mRNA vaccine-dose and controls on sex, age, province, first dose type and time, month of primary infection and number of previous tests. We then estimated Kaplan-Meier risks of confirmed SARS-CoV-2 reinfection. We performed a similar analysis in a Delta-dominant period, between July 19 and November 30, 2021.In the Omicron period, estimated effectiveness (95% confidence interval) of a second dose was 62.2% (58.2, 66.4) 7 to 34 days after administration, similar across groups defined by age, sex, type of first vaccine and time since the first dose. Estimated effectiveness was 65.4% (61.1, 69.9) for mRNA-1273 and 52.0% (41.8, 63.1) for BNT162b2. Estimated effectiveness was 78.5% (67.4, 89.9), 66.1% (54.9, 77.5), and 60.2% (55.5, 64.8) when primary infection had occurred in the Delta, Alpha, and pre-Alpha periods, respectively. In the Delta period, the estimated effectiveness of a second dose was 8.8% (-55.3, 81.1).Our results suggest that, over a month after administration, a second dose of mRNA vaccine increases protection against SARS-CoV-2 reinfection with the Omicron variant among individuals with single-dose vaccination and previously infected with another variant.

Background: With the emergence of SARS-CoV-2, influenza surveillance systems in Spain were transformed into a new syndromic sentinel surveillance system. The Acute Respiratory Infection Surveillance System (SiVIRA in Spanish) is based on a sentinel network for Acute Respiratory Infection (ARI) surveillance in Primary care, and a network of sentinel hospitals for Severe ARI (SARI) surveillance in hospitals. Methods: Using a test-negative design and data from SARI admissions notified to SiVIRA between January 1 and October 3, 2021, we estimated COVID-19 VE against hospitalization, by age group, vaccine type, time since vaccination and SARS-CoV-2 variant. Results: VE was 89% (95% CI: 83-93) against COVID-19 hospitalization overall in persons aged 20 years and older. VE was higher for mRNA vaccines, and lower for those aged 80 years and older, with a decrease in protection beyond 3 months of completing vaccination, and a further decrease after 5 months. We found no differences between periods with circulation of Alpha or Delta SARS-CoV-2 variants, although variant-specific VE was slightly higher against Alpha. Conclusions: The SiVIRA surveillance system, with a network of sentinel hospitals in Spain was able to describe clinical and epidemiological characteristics of SARI hospitalizations, monitor the circulation of SARS-CoV-2 and other respiratory viruses, and provide data to measure the effectiveness of COVID-19 vaccination in the population under surveillance. Our results add to evidence of high VE of mRNA vaccines against severe COVID-19 and waning protection with time since vaccination.

Factor de impacto: 25,71 Q1 Background: The omicron (B.1.1.529) variant of SARS-CoV-2 has increased capacity to elude immunity and cause breakthrough infections. The aim of this study was to estimate the effectiveness of mRNA-based vaccine boosters (third dose) against infection with the omicron variant by age, sex, time since complete vaccination, type of primary vaccine, and type of booster. Methods: In this nationwide cohort study, we linked data from three nationwide population registries in Spain (Vaccination Registry, Laboratory Results Registry, and National Health System registry) to select community-dwelling individuals aged 40 years or older, who completed their primary vaccine schedule at least 3 months before the start of follow-up, and had not tested positive for SARS-CoV-2 since the start of the pandemic. On each day between Jan 3, and Feb 6, 2022, we matched individuals who received a booster mRNA vaccine and controls of the same sex, age group, postal code, type of vaccine, time since primary vaccination, and number of previous tests. We estimated risk of laboratory-confirmed SARS-CoV-2 infection using the Kaplan-Meier method and compared groups using risk ratios (RR) and risk differences. Vaccine effectiveness was calculated as one minus RR. Findings: Between Jan 3, and Feb 6, 2022, 3 111 159 matched pairs were included in our study. Overall, the estimated effectiveness from day 7 to 34 after a booster was 51·3% (95% CI 50·2-52·4). Estimated effectiveness was 52·5% (51·3-53·7) for an mRNA-1273 booster and 46·2% (43·5-48·7) for a BNT162b2 booster. Effectiveness was 58·6% (55·5-61·6) if primary vaccination had been with ChAdOx1 nCoV-19 (Oxford-AstraZeneca), 55·3% (52·3-58·2) with mRNA-1273 (Moderna), 49·7% (48·3-51·1) with BNT162b2 (Pfizer-BioNTech), and 48·0% (42·5-53·7) with Ad26.COV2.S (Janssen). Estimated effectiveness was 43·6% (40·0-47·1) when the booster was administered between 151 days and 180 days after complete vaccination and 52·2% (51·0-53·3) if administered more than 180 days after primary scheduled completion. Interpretation: Booster mRNA vaccine-doses were moderately effective in preventing infection with the omicron variant of SARS-CoV-2 for over a month after administration, which indicates their suitability as a strategy to limit the health effects of COVID-19 in periods of omicron variant domination. Estimated effectiveness was higher for mRNA-1273 compared with BNT162b2 and increased with time between completed primary vaccination and booster. Sí

In this paper we compared brand-specific COVID-19 vaccine effectiveness (VE) during August 2021 in persons born 1962-1971 and vaccinated during June. For SARS-CoV-2 symptomatic infection, protection was lower for Janssen (56%; CI95%: 53-59) or AstraZeneca [Vaxzevria] (68%; CI95%: 65-70), compared to Pfizer-BioNTech [Comirnaty] (78%; CI95%: 77-78), AstraZeneca/Pfizer (86%; CI95%: 80-90) or Moderna [Spikevax] (89%; CI95%: 88-90). VE against hospitalization was ranged 86% for Janssen to 97%-98% for other vaccines.En este trabajo se comparó la efectividad de la vacuna contra la COVID-19 (EV) durante agosto de 2021, en personas nacidas entre 1962 y 1971 y vacunadas durante junio, según la marca utilizada. La protección frente a infección por SARS-CoV-2 sintomática fue menor para la vacuna de Janssen (56%; IC95%: 53-59) y AstraZeneca [Vaxzevria] (68%; IC95%: 65-70), en comparación con Pfizer [Comirnaty] (78%; IC95%: 77-78), AZ/Pfizer (86%; IC95%: 80-90) y Moderna [Spikevax] (89%; IC95%: 88-90). La EV contra la hospitalización osciló entre el 86% de Janssen y el 97%-98% de las demás vacunas.

Background: Seasonal influenza-associated excess mortality estimates can be timely and provide useful information on the severity of an epidemic. This methodology can be leveraged during an emergency response or pandemic. Method: For Denmark, Spain, and the United States, we estimated age-stratified excess mortality for (i) all-cause, (ii) respiratory and circulatory, (iii) circulatory, (iv) respiratory, and (v) pneumonia, and influenza causes of death for the 2015/2016 and 2016/2017 influenza seasons. We quantified differences between the countries and seasonal excess mortality estimates and the death categories. We used a time-series linear regression model accounting for time and seasonal trends using mortality data from 2010 through 2017. Results: The respective periods of weekly excess mortality for all-cause and cause-specific deaths were similar in their chronological patterns. Seasonal all-cause excess mortality rates for the 2015/2016 and 2016/2017 influenza seasons were 4.7 (3.3-6.1) and 14.3 (13.0-15.6) per 100,000 population, for the United States; 20.3 (15.8-25.0) and 24.0 (19.3-28.7) per 100,000 population for Denmark; and 22.9 (18.9-26.9) and 52.9 (49.1-56.8) per 100,000 population for Spain. Seasonal respiratory and circulatory excess mortality estimates were two to three times lower than the all-cause estimates. Discussion: We observed fewer influenza-associated deaths when we examined cause-specific death categories compared with all-cause deaths and observed the same trends in peaks in deaths with all death causes. Because all-cause deaths are more available, these models can be used to monitor virus activity in near real time. This approach may contribute to the development of timely mortality monitoring systems during public health emergencies. This study was conducted as part of Sebastian Schmidt's research fellowship, which was financially supported by the Novo Nordic Foundation and A.P. Møller Fonden. The EuroMOMO network has received financial support from the European Centre for Disease Prevention and Control (ECDC) and from the World Health Organization (WHO) Regional Office for Europe. Sí

IntroductionIn July and August 2021, the SARS-CoV-2 Delta variant dominated in Europe. We measured COVID-19 vaccine effectiveness (VE) against symptomatic infection, using a multicentre test-negative study at primary care/community level in Europe.MethodsPatients presenting with COVID-19/ARI symptoms at primary care/community level in 10 countries were tested for SARS-CoV-2. We measured complete primary course overall VE among those aged 30–44, 45–59, 60–74 and ≥75 years, and among those 30–59 and ≥60 years by vaccine brand and by time since vaccination.ResultsOverall VE was 74% (95%CI: 69–79), 76% (95%CI: 71–80), 63% (95%CI: 48–75), 63% (95%CI: 16–83) among those aged 30–44, 45–59, 60–74 and ≥75 years, respectively. VE among those aged 30–59 years was 78% (95%CI: 75–81), 66% (95%CI: 58–73), 91% (95%CI: 87–94) and 52% (95%CI: 40–61), for Comirnaty, Vaxzevria, Spikevax and COVID-19 Vaccine Janssen, respectively. VE among those aged ≥60 years was 67% (95%CI: 52–77), 65% (95%CI: 48–76), 83% (95%CI: 64–92) for Comirnaty, Vaxzevria and Spikevax, respectively. Comirnaty VE among those aged 30–59 years was 87% (95%CI: 83–89) and 65% (95%CI: 56–71%) at 14–29 days and ≥90 days between vaccination and onset of symptoms, respectively.ConclusionsVE against the symptomatic SARS-CoV-2 Delta variant infection varied among brands, ranging from 52–91%. While some waning of the vaccine effect may be present (sample size limited this analysis to only Comirnaty), protection was 65% ≥90 days between vaccination and onset.

Background On June 21st de-escalation measures and state-of-alarm ended in Spain after the COVID-19 first wave. New surveillance and control strategy was set up to detect emerging outbreaks. Aim To detect and describe the evolution of COVID-19 clusters and cases during the 2020 summer in Spain. Methods A near-real time surveillance system to detect active clusters of COVID-19 was developed based on Kulldorf’s prospective space-time scan statistic (STSS) to detect daily emerging active clusters. Results Analyses were performed daily during the summer 2020 (June 21st – August 31st) in Spain, showing an increase of active clusters and municipalities affected. Spread happened in the study period from a few, low-cases, regional-located clusters in June to a nationwide distribution of bigger clusters encompassing a higher average number of municipalities and total cases by end-August. Conclusion STSS-based surveillance of COVID-19 can be of utility in a low-incidence scenario to help tackle emerging outbreaks that could potentially drive a widespread transmission. If that happens, spatial trends and disease distribution can be followed with this method. Finally, cluster aggregation in space and time, as observed in our results, could suggest the occurrence of community transmission.

Since December 2019, over 1.5 million SARS-CoV-2-related fatalities have been recorded in the World Health Organization European Region - 90.2% in people ≥ 60 years. We calculated lives saved in this age group by COVID-19 vaccination in 33 countries from December 2020 to November 2021, using weekly reported deaths and vaccination coverage. We estimated that vaccination averted 469,186 deaths (51% of 911,302 expected deaths; sensitivity range: 129,851–733,744; 23–62%). Impact by country ranged 6–93%, largest when implementation was early.

Chagas disease is emerging in countries to which it is not endemic. Biomarkers for earlier therapeutic response assessment in patients with chronic Chagas disease are needed. We profiled plasma-derived extracellular vesicles from a heart transplant patient with chronic Chagas disease and showed the potential of this approach for discovering such biomarkers. Barcelona Institute for Global Health (ISGlobal) receives support from the Spanish Ministry of Science, Innovation and Universities through the Centro de Excelencia Severo Ochoa 2019–2023 Program (CEX2018-000806-S). ISGlobal and Institut d’Investigació en Ciències de la Salut Germans Trias i Pujol (IGTP) are members of the Centres de Recerca de Catalunya (CERCA Program), Generalitat de Catalunya. Work in the laboratory of C.F.B. is funded by Fundació La Marató de TV3 (reference 566/U/2018) and Fundación Mundo Sano. This project was co-financed by the European Union through the European Regional Development Fund with the support of Secretaria d’Universitats i Recerca del Departament d’Empresa i Coneixement de la Generalitat de Catalunya. N.C., M.G., J.G., and M.J.P. receive funds from the Redes temáticas de investigación cooperativa en salud (RETICS), Spanish Tropical Diseases Network “RD12/0018/0010” and from the Agencia de Gestió d’Ajuts Universitaris i de Recerca, Generalitat de Catalunya; grant “2017 SGR 00924.” M.G., C.B., J.G., M.J.P., and I.C.A. belong to the Ibero-American Nuevas Herramientas para el Diagnóstico y la Evaluación del Paciente con Enfermedad de Chagas network. I.C.A. is partially supported by grants no. 2G12MD007592 and 5U54MD007592 from the National Institute on Minority Health and Health Disparities of the US National Institutes of Health. We are grateful to the Biomolecule Analysis Core Facility at University of Texas at El Paso, Border Biomedical Research Center, funded by National Institute on Minority Health and Health Disparities grants 2G12MD007592 and 5U54MD007592. M.T.M. received a PhD fellowship from the Science Without Borders Program, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, Brazil. Sí

Background To increase the acceptability of influenza vaccine, it is important to quantify the overall benefits of the vaccination programme. Aim To assess the impact of influenza vaccination in Portugal, Spain and the Netherlands, we estimated the number of medically attended influenza-confirmed cases (MAICC) in primary care averted in the seasons 2015/16 to 2017/18 among those ≥ 65 years. Methods We used an ecological approach to estimate vaccination impact. We compared the number of observed MAICC (n) to the estimated number that would have occurred without the vaccination programme (N). To estimate N, we used: (i) MAICC estimated from influenza surveillance systems, (ii) vaccine coverage, (iii) pooled (sub)type-specific influenza vaccine effectiveness estimates for seasons 2015/16 to 2017/18, weighted by the proportion of virus circulation in each season and country. We estimated the number of MAICC averted (NAE) and the prevented fraction (PF) by the vaccination programme. Results The annual average of NAE in the population ≥ 65 years was 33, 58 and 204 MAICC per 100,000 in Portugal, Spain and the Netherlands, respectively. On average, influenza vaccination prevented 10.7%, 10.9% and 14.2% of potential influenza MAICC each season in these countries. The lowest PF was in 2016/17 (4.9–6.1%) with an NAE ranging from 24 to 69 per 100,000. Conclusions Our results suggest that influenza vaccination programmes reduced a substantial number of MAICC. Together with studies on hospitalisations and deaths averted by influenza vaccination programmes, this will contribute to the evaluation of the impact of vaccination strategies and strengthen public health communication.

European IVE Group - Portuguese Team: Verónica Gomez, Irina Kislaya, Baltazar Nunes, Ana Paula Rodrigues Ausenda Machado (Departamento de Epidemiologia, Instituto Nacional de Saúde Doutor Ricardo Jorge); Patrícia Conde, Inês Costa, Paula Cristóvão, Pedro Pechirra, Raquel Guiomar (Departamento de Doenças Infeciosas, Instituto Nacional de Saúde Doutor Ricardo Jorge). Seasonal influenza vaccine is recommended in all European Union (EU) countries for older people and others at increased risk of severe influenza and its complications, including those with chronic diseases. In the United Kingdom (UK), incremental introduction of a universal childhood influenza vaccination programme began in 2013/14. The World Health Organization (WHO) recommendations for trivalent influenza vaccine strains for the 2018/19 northern hemisphere influenza season included an A/Michigan/45/2015 (H1N1)pdm09-like virus, an A/Singapore/INFIMH-16–0019/2016 (H3N2)-like virus and a B/Colorado/06/2017-like virus from the B/Victoria lineage. The early 2018/19 influenza season in Europe was characterised by both influenza A virus subtypes circulating widely. There was co-circulation in some countries, with others reporting dominance of either A(H1N1)pdm09 or A(H3N2) viruses. The season started late in most countries compared with previous seasons, with few influenza B viruses detected in the WHO European Region. Since the 2008/09 season, the UK, Denmark, Spain, and several other EU countries conducting multicentre studies, have participated in I-MOVE (Influenza – Monitoring Vaccine Effectiveness in Europe), a network measuring influenza vaccine effectiveness each season. Interim results from six established influenza VE studies across Europe for the 2018/19 season indicate that VE against laboratory-confirmed influenza A ranged between 32% and 43% among all ages in primary care and hospital settings and was 59% in the target groups for vaccination. ECDC info:eu-repo/semantics/publishedVersion

Objectives: Weekly monitoring of European all-cause excess mortality, the EuroMOMO network, observed high excess mortality during the influenza B/Yamagata dominated 2017/18 winter season, especially among elderly. We describe all-cause excess and influenza-attributable mortality during the season 2017/18 in Europe. Methods: Based on weekly reporting of mortality from 24 European countries or sub-national regions, representing 60% of the European population excluding the Russian and Turkish parts of Europe, we estimated age stratified all-cause excess morality using the EuroMOMO model. In addition, age stratified all-cause influenza-attributable mortality was estimated using the FluMOMO algorithm, incorporating influenza activity based on clinical and virological surveillance data, and adjusting for extreme temperatures. Results: Excess mortality was mainly attributable to influenza activity from December 2017 to April 2018, but also due to exceptionally low temperatures in February-March 2018. The pattern and extent of mortality excess was similar to the previous A(H3N2) dominated seasons, 2014/15 and 2016/17. The 2017/18 overall all-cause influenza-attributable mortality was estimated to be 25.4 (95%CI 25.0-25.8) per 100,000 population; 118.2 (116.4-119.9) for persons aged 65. Extending to the European population this translates into over-all 152,000 deaths. Conclusions: The high mortality among elderly was unexpected in an influenza B dominated season, which commonly are considered to cause mild illness, mainly among children. Even though A(H3N2) also circulated in the 2017/18 season and may have contributed to the excess mortality among the elderly, the common perception of influenza B only having a modest impact on excess mortality in the older population may need to be reconsidered. info:eu-repo/semantics/publishedVersion