Browsing by Author "Pereira da Silva, Susana"
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- Cross-protection to new drifted influenza A(H3) viruses and prevalence of protective antibodies to seasonal influenza, during 2014 in PortugalPublication . Guiomar, Raquel; Pereira da Silva, Susana; Conde, Patrícia; Cristóvão, Paula; Maia, Ana Carina; Pechirra, Pedro; Rodrigues, Ana Paula; Nunes, Baltazar; Milho, Luís; Coelho, Ana Paula; Fernandes, Aida; Caseiro, Paula; Rodrigues, Fernando; Correia, Lurdes; Pereira-Vaz, João; Almeida, Sofia; Branquinho, Paula; Côrte-Real, Rita; Viseu, Regina; Peres, Maria João; Sanches, Raquel; Dantas, Filipa; Freitas, Ludovina; Andrade, Graça; Maurílio, Manuel; Caldeira, Filomena; Cabral Veloso, Rita; Mota-Vieira, Luísa; Soares, Marta; Couto, Ana Rita; Bruges-Armas, Jácome; Mouro Pinto, Rita; Sobrinho Simões, Joana; Rosário Costa, Maria; Guimarães, João Tiago; Martins, Luís; Cunha, MárioIntroduction: 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 crossprotection 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 65 years 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.
- Cross-protection to new drifted influenza A(H3) viruses and prevalence of protective antibodies to seasonal influenza, during 2014 in PortugalPublication . Guiomar, Raquel; Pereira da Silva, Susana; Conde, Patrícia; Cristóvão, Paula; Maia, Ana Carina; Pechirra, Pedro; Rodrigues, Ana Paula; Nunes, Baltazar; Milho, Luís; Coelho, Ana Paula; Fernandes, Aida; Caseiro, Paula; Rodrigues, Fernando; Correia, Lurdes; Pereira-Vaz, João; Almeida, Sofia; Branquinho, Paula; Côrte-Real, Rita; Viseu, Regina; Peres, Maria João; Sanches, Raquel; Dantas, Filipa; Freitas, Ludovina; Andrade, Graça; Maurílio, Manuel; Caldeira, Filomena; Cabral Veloso, Rita; Mota-Vieira, Luísa; Soares, Marta; Couto, Ana Rita; Bruges-Armas, Jácome; Mouro Pinto, Rita; Sobrinho Simões, Joana; Costa, Maria do Rosário; Guimarães, João Tiago; Martins, Luís; Cunha, MárioIntroduction: 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 65 years 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.
- EQA in Air Microbiology - PNAEQ 2019Publication . Cano, Manuela; Correia, Helena; Pereira da Silva, Susana; Faria, Ana PaulaEQA implemented in 2010; Evaluation of the air sampling and analysis for the quantification of airborne bacteria and fungi: Sampling equipment used; Culture media (2012); Incubation temperature; Evaluation at 2 different sampling points (different 2 rounds per year (summer and winter).
- Influenza seroprotection correlates with predominant circulating viruses during 2014/15 and 2015/16 seasons in PortugalPublication . Guiomar, Raquel; Cristóvão, Paula; Conde, Patrícia; Costa, Inês; Pechirra, Pedro; Rodrigues, Ana Paula; Pereira da Silva, Susana; Nunes, Baltazar; Mouro Pinto, Rita; Sobrinho Simões, Joana; Costa, Maria do Rosário; Guimarães, João Tiago; Rodrigues, Fernando; Correia, Lurdes; Pereira-Vaz, João; Caseiro, Paula; Cabral Veloso, Rita; Mota Vieira, Luísa; Pimentel Couto, Ana Rita; Santos, Margarida; Bruges Armas, Jácome; Branquinho, Paula; Corte-Real, Rita; Martins, Luís; Cunha, Mário; Almeida, Sofia; Viseu, Regina; Inácio, Filipe; Peres, Maria João; Milho, Luís; Fernandes, Aida; Maurílio, Manuel; Caldeira, Filomena; Sanches, Raquel; Dantas, Filipa; Freitas, Ludivina; Andrade, Graça; Mota, PaulaBACKGROUND: Population immune profile for influenza is highly affected by circulating influenza viruses, thus changing the risk of infection for influenza. This study aims to assess influenza immunity in the Portuguese population by age groups, during 2014 and 2015 and establish a relationship between seroprotection and circulating influenza viruses in 2014/15 and 2015/16 seasons. METHODS: Two cross-sectional studies were developed based on a convenience serum sample collected in June 2014 (n=626) and July 2015 (n=675) in hospitals from mainland and Azores and Madeira.Serums equally represent all age groups. Antibody titers were evaluated by HI assay for strains recommended for seasonal influenza vaccine northern hemisphere,2014/15 and 2015/2016. Seroprevalences were estimated for each strain by age group and the association with seasonal cumulative influenza-like illness (ILI) rates for influenza virus during both seasons was analised. RESULTS: In June 2014 the highest seroprotection was observed for influenza A(H3) (39.0%; 95% CI: 36.2-43.8%) and A(H1)pdm09 (29.7; 95% CI: 26.3-33.4%), with higher levels in children 5-14 years old. In 2014/2015 a dominant circulation of influenza B/Yamagata was observed with high incidence rates in individuals under 65 years old, the ones that had lower seroprotection. Although before the start of the season high protection for A(H3) was observed, the circulation of the new drift A(H3) strains had gained an immunological advantage,in accordance with A(H3) elevated incidence rates observed during 2014/15. In July 2015 the highest seroprotection was observed for influenza B/ Yamagata (55.1%; 95% CI: 51.4-58.9%), 2.4 times the estimated 2014.This increase was even more pronounced in younger (≤ 4 years old), 6.3 times increase in 2015.This fact is in agreement with the predominant influenza B virus detected and the high ILI incidence rate observed in children during 2014/2015 epidemic. Seroprotection levels for influenza A in July 2015 were not significantly different from 2014.During 2015/16 season, influenza A(H1N1)pdm09 was predominant, with high incidence rate in < 65 year old. Influenza B/Victoria lineage,although detected at low levels increased in frequency, in agreement with the lowest level of seroprotection detected in the general population before the start of 2015/2016 season (21.8%; 95% CI: 18.7-24.0%). CONCLUSIONS There was a correlation between virus circulation, incidence rates for each age group and the previous seroprotection for seasonal influenza viruses.Our study highlights the value of measuring the serological profile for influenza to establishe risk groups for infection for which an increase preventive measures, including vaccination, should be fostered.
- Influenza surveillance during 2015/2016 season in PortugalPublication . Guiomar, Raquel; Pechirra, Pedro; Cristóvão, Paula; Costa, Inês; Conde, Patrícia; Pereira da Silva, Susana; Nunes, Baltazar; Rodrigues, Ana PaulaBackground: The National Influenza Surveillance Program ensures influenza epidemiological surveillance, integrating clinical and laboratory data. The clinical component describes the transmissibility over time, the virological component detects and characterizes influenza virus in circulation. Data is generated through 2 sentinel surveillance structures, the General Practitioner’s Sentinel Network (since 1990) and the Network of Emergency Units (since 1999). Here we provide the evaluation of 2015/2016 influenza season in Portugal. Methods: Influenza-Like illness (ILI) cases were reported to the National Influenza Reference Laboratory and to the Epidemiology Department of the National Institute of Health, in the context of the National Influenza Surveillance Program, from week 39/2015 through week 20/2016. The intensity and duration of the epidemic period were described based on the weekly ILI incidence rates. Nasopharyngeal swabs were collected for influenza and other respiratory viruses (RV: respiratory syncytial virus, adenovirus, rhinovirus, metapneumovirus, coronavirus, parainfluenza virus) for diagnosis and characterization. The detection of influenza and RV was performed by multiplex real-time RT-PCR. Influenza virus isolation, antigenic analysis (hemagglutination inhibition assay) and genetic characterization (HA1 gene segment) were performed. Results: During 2015/2016 season the influenza activity was low and the epidemic period occurred between week 1/2016 and 9/2016 with a maximum of 59.4 ILI cases per 105 inhabitants in week 3/2016. No impact on mortality from all causes was observed in any age group. 1097 nasopharyngeal swabs were tested for influenza and other respiratory viruses, influenza was detected in 444 (41%) and others respiratory viruses were found in 265 (24%). The influenza A(H1)pdm09 was predominant (91% of flu confirmed cases). Influenza B/ Victoria was identified sporadically (7% of flu cases) in late season. A(H1)pdm09 were predominantly detected in adults aged 15-64. Other respiratory viruses were detected in influenza negative cases, being rhinovirus (101; 38%) and coronavirus (78; 29%) found in higher frequencies. The antigenic and genetic analysis of circulating influenza A(H1)pdm09 showed similarity with vaccine strain. The majority of influenza B virus belonged to Victoria lineage and clade 1A, dissimilar from 2015/16 vaccine strain. Although few A(H3) viruses in circulation, almost all were similar to strain recommended for next season, 2016/2017, influenza vaccine. None of the 420 A(H1)pdm09 viruses analysed showed the H275Y substitution, correlated to high reduced susceptibility to oseltamivir. Conclusions: Influenza activity during 2015/2016 flu season was low, that can be linked with a higher influenza activity in last season and exceptional climatic conditions during the winter (higher temperature than usual). A(H1pdm)09 viruses were dominant, although in co-circulation with influenza B/Victoria. Situation that contrasts with European influenza picture, that showed a late peak of influenza B/ Victoria. Influenza A(H1)pdm09 detections reached the highest percentage in adults (15-64 years old). Most influenza detected viruses were similar to the 2015/2016 vaccine strains, although circulating influenza B/Victoria were from a different lineage comparing with vaccine strain. Observed mortality from all causes was within expected values during study period.