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Browsing by Author "Peres, MJ"

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  • Cross-Protection to New Drifted Influenza A(H3) Viruses and Prevalence of Protective Antibodies to Seasonal Influenza, During 2014 in Portugal
    Publication . Guiomar, R; Pereira da Silva, S; Conde, P; Cristóvão, P; Maia, AC; Pechirra, P; Rodrigues, AP; Nunes, B; Milho, L; Coelho, AP; Fernandes, A; Caseiro, P; Rodrigues, F; Correia, L; Pereira-Vaz, J; Almeida, S; Branquinho, P; Côrte-Real, R; Viseu, R; Peres, MJ; Sanches, R; Dantas, F; Freitas, L; Andrade, G; Maurílio, M; Caldeira, F; Cabral Veloso, R; Mota-Vieira, L; Soares, M; Couto, AR; Bruges-Armas, J; Mouro Pinto, R; Sobrinho Simões, J; Costa, MR; Guimarães, JT; Martins, L; Cunha, M
    INTRODUCTION: Immune profile for influenza viruses is highly changeable over time. Serological studies can assess the prevalence of influenza, estimate the risk of infection, highlight asymptomatic infection rate and can also provide data on vaccine coverage. The aims of the study were to evaluate pre-existing cross-protection against influenza A(H3) drift viruses and to assess influenza immunity in the Portuguese population. MATERIALS AND METHODS: We developed a cross-sectional study based on a convenience sample of 626 sera collected during June 2014, covering all age groups, both gender and all administrative health regions of Portugal. Sera antibody titers for seasonal and new A(H3) drift influenza virus were evaluated by hemagglutination inhibition assay (HI). Seroprevalence to each seasonal influenza vaccine strain virus and to the new A(H3) drift circulating strain was estimated by age group, gender and region and compared with seasonal influenza-like illness (ILI) incidence rates before and after the study period. RESULTS: Our findings suggest that seroprevalences of influenza A(H3) (39.9%; 95% CI: 36.2-43.8) and A(H1)pdm09 (29.7%; 95% CI: 26.3-33.4) antibodies were higher than for influenza B, in line with high ILI incidence rates for A(H3) followed by A(H1)pdm09, during 2013/2014 season. Low pre-existing cross-protection against new A(H3) drift viruses were observed in A(H3) seropositive individuals (46%). Both against influenza A(H1)pdm09 and A(H3) seroprotection was highest in younger than 14-years old. Protective antibodies against influenza B were highest in those older than 65years old, especially for B/Yamagata lineage, 33.3% (95% CI: 25.7-41.9). Women showed a high seroprevalence to influenza, although without statistical significance, when compared to men. A significant decreasing trend in seroprotection from north to south regions of Portugal mainland was observed. CONCLUSIONS: Our results emphasize that low seroprotection increases the risk of influenza infection in the following winter season. Seroepidemiological studies can inform policy makers on the need for vaccination and additional preventive measures.
    2017Journal article Open access Show more
  • Implementing an Influenza Vaccine Effectiveness Study in a Hospital Context in Portugal: The EVA Hospital Project
    Publication . Machado, A; Gomez, V; Panarra, A; Poças, J; Corte-Real, R; Peres, MJ; Nunes, B
    Introduction: The project ‘Integrated Monitoring of Vaccines in Europe’ aimed to measure seasonal influenza vaccine effectiveness against hospitalised adults, aged 65 years and over, with influenza. We describe the protocol implementation in Portugal. Material and Methods: We implemented a test-negative design, targeting community-dwelling patients aged 65 years old and over hospitalised with severe acute respiratory illness. Patients were reverse transverse-polymerase chain reaction tested for influenza. Cases were those positive for influenza while others were controls. Most variables were collected using hospital medical records. Selection bias was evaluated by comparison with the laboratory influenza test requests database according to demographic characteristics. Crude, season-adjusted influenza vaccine effectiveness was estimated as = 1 – odds ratio, and 95% confidence intervals were obtained by conditional logistical regression, matched with the disease onset month. Results: The recruitment rate was 37.8%. Most participants (n = 368) were female (55.8%) and aged 80 years old and over (55.8%). This was similar to values for potentially eligible severe acute respiratory illness patients (80 years old and over: 56.8%, female: 56.2%). The proportion of missing values was below 2.5% for 20 variables and above 5% (maximum 11.6%) for six variables. Influenza vaccine effectiveness estimates were 62.1% against AH1pdm09 (95% confidence intervals: -28.1 to 88.8), 14.9% against A(H3N2) (95% confidence intervals: -69.6 to 57.3), 43.6% against B/Yam (95% confidence intervals: -66.2 to 80.8). Discussion: Given the non-existence of a coded admission database in either participating hospital the selection of severe acute respiratory illness due to clinical features was the feasible one. These results are only valid for the older adult population residing in the catchment area of the two participating hospitals who were admitted to a public hospital with severe influenza or SARI symptoms. Conclusion: Despite the low participation rate, we observed comparable characteristics of participants and eligible severe acute respiratory illness patients. Data quality was high, and influenza vaccine effectiveness results were in accordance with the results of meta-analyses and European season-specific estimates. The final sample size was low, which inhibited obtaining estimates with good precision.
    2021-01Journal article Open access Show more
  • Rastreio Neonatal de Hemoglobinopatias numa População Residente em Portugal
    Publication . Peres, MJ; Carreiro, MH; Machado, MC; Seixas, T; Picanço, I; Batalha, L; Lavinha, J; Martins, MC
    The primary objective of newborn screening of hemoglobinopathies is the early identification of infants with sickle cell disease, as they are at increased clinical risk. Other goals include the identification of other types of clinically significant hemoglobinopathies and the detection of heterozygous carriers followed by the screening and counselling of family members. We performed a pilot study for the neonatal screening of hemoglobinopathies in 400 samples of cord blood taken from a maternity in Lisbon. We did not find any newborn with sickle cell disease. Six samples were from sickle cell heterozygotes, the respective families were studied and informed. We looked for the presence of alpha-thalassemia at birth in 100 consecutive samples of cord blood, by the presence of Hb Bart's, abnormal red blood cell indices and alpha-globin genotype. The results show an incidence of 10% of alpha-thalassemia (-alpha) carriers and 4% of triple alpha-globin gene carriers. The authors discuss the feasibility of neonatal screening of hemoglobinopathies in a Portuguese-speaking population consisting of a low prevalence of Hb S trait autoclonous group and a high prevalence immigrant minority
    1996Journal article Open access Show more