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1.
MMWR Morb Mortal Wkly Rep ; 69(7): 177-182, 2020 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-32078591

RESUMO

During the 2019-20 influenza season, influenza-like illness (ILI)* activity first exceeded the national baseline during the week ending November 9, 2019, signaling the earliest start to the influenza season since the 2009 influenza A(H1N1) pandemic. Activity remains elevated as of mid-February 2020. In the United States, annual vaccination against seasonal influenza is recommended for all persons aged ≥6 months (1). During each influenza season, CDC estimates seasonal influenza vaccine effectiveness in preventing laboratory-confirmed influenza associated with medically attended acute respiratory illness (ARI). This interim report used data from 4,112 children and adults enrolled in the U.S. Influenza Vaccine Effectiveness Network (U.S. Flu VE Network) during October 23, 2019-January 25, 2020. Overall, vaccine effectiveness (VE) against any influenza virus associated with medically attended ARI was 45% (95% confidence interval [CI] = 36%-53%). VE was estimated to be 50% (95% CI = 39%-59%) against influenza B/Victoria viruses and 37% (95% CI = 19%-52%) against influenza A(H1N1)pdm09, indicating that vaccine has significantly reduced medical visits associated with influenza so far this season. Notably, vaccination provided substantial protection (VE = 55%; 95% CI = 42%-65%) among children and adolescents aged 6 months-17 years. Interim VE estimates are consistent with those from previous seasons, ranging from 40%-60% when influenza vaccines were antigenically matched to circulating viruses. CDC recommends that health care providers continue to administer influenza vaccine to persons aged ≥6 months because influenza activity is ongoing, and the vaccine can still prevent illness, hospitalization, and death associated with currently circulating influenza viruses as well as other influenza viruses that might circulate later in the season.


Assuntos
Vírus da Influenza A Subtipo H1N1/isolamento & purificação , Vírus da Influenza A Subtipo H3N2/isolamento & purificação , Vírus da Influenza B/isolamento & purificação , Vacinas contra Influenza/administração & dosagem , Influenza Humana/prevenção & controle , Vigilância da População , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Vacinas contra Influenza/imunologia , Influenza Humana/epidemiologia , Influenza Humana/virologia , Masculino , Pessoa de Meia-Idade , Estações do Ano , Estados Unidos/epidemiologia , Adulto Jovem
2.
MMWR Morb Mortal Wkly Rep ; 68(40): 880-884, 2019 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-31600182

RESUMO

During May 19-September 28, 2019,* low levels of influenza activity were reported in the United States, with cocirculation of influenza A and influenza B viruses. In the Southern Hemisphere seasonal influenza viruses circulated widely, with influenza A(H3) predominating in many regions; however, influenza A(H1N1)pdm09 and influenza B viruses were predominant in some countries. In late September, the World Health Organization (WHO) recommended components for the 2020 Southern Hemisphere influenza vaccine and included an update to the A(H3N2) and B/Victoria-lineage components. Annual influenza vaccination is the best means for preventing influenza illness and its complications, and vaccination before influenza activity increases is optimal. Health care providers should recommend vaccination for all persons aged ≥6 months who do not have contraindications to vaccination (1).


Assuntos
Saúde Global/estatística & dados numéricos , Vacinas contra Influenza/química , Influenza Humana/epidemiologia , Vigilância da População , Farmacorresistência Viral , Humanos , Vírus da Influenza A Subtipo H1N1/efeitos dos fármacos , Vírus da Influenza A Subtipo H1N1/genética , Vírus da Influenza A Subtipo H1N1/isolamento & purificação , Vírus da Influenza A Subtipo H3N2/efeitos dos fármacos , Vírus da Influenza A Subtipo H3N2/genética , Vírus da Influenza A Subtipo H3N2/isolamento & purificação , Vírus da Influenza B/efeitos dos fármacos , Vírus da Influenza B/genética , Vírus da Influenza B/isolamento & purificação , Influenza Humana/virologia , Estações do Ano , Estados Unidos/epidemiologia
3.
Emerg Microbes Infect ; 8(1): 1280-1290, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31495283

RESUMO

The H3N2 influenza viruses became widespread in humans during the 1968 H3N2 pandemic and have been a major cause of influenza epidemics ever since. Different lineages of H3N2 influenza viruses are also commonly found in animals. If a different lineage of H3N2 virus jumps to humans, a human influenza pandemic could occur with devastating consequences. Here, we studied the genetics, receptor-binding properties, and replication and transmission in mammals of 15 H3N2 avian influenza viruses detected in live poultry markets in China. We found that the H3N2 avian influenza viruses are complicated reassortants with distinct replication phenotypes in mice. Five viruses replicated efficiently in mice and bound to both human-type and avian-type receptors. These viruses transmitted efficiently to direct-contact guinea pigs, and three of them also transmitted among guinea pigs and ferrets via respiratory droplets. Moreover, ferret antiserum induced by human H3N2 viruses did not react with any of the H3N2 avian influenza viruses. Our study demonstrates that the H3N2 avian influenza viruses pose a clear threat to human health and emphasizes the need for continued surveillance and evaluation of the H3N2 influenza viruses circulating in nature.


Assuntos
Transmissão de Doença Infecciosa , Vírus da Influenza A Subtipo H3N2/isolamento & purificação , Vírus da Influenza A Subtipo H3N2/fisiologia , Influenza Aviária/virologia , Aves Domésticas/virologia , Ligação Viral , Animais , China , Modelos Animais de Doenças , Furões , Cobaias , Humanos , Vírus da Influenza A Subtipo H3N2/genética , Camundongos Endogâmicos BALB C , Vírus Reordenados/genética , Vírus Reordenados/isolamento & purificação , Vírus Reordenados/fisiologia , Receptores Virais/metabolismo , Doenças dos Roedores/virologia , Replicação Viral
4.
BMC Infect Dis ; 19(1): 676, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31370782

RESUMO

BACKGROUND: In addition to seasonal influenza viruses recently circulating in humans, avian influenza viruses (AIVs) of H5N1, H5N6 and H7N9 subtypes have also emerged and demonstrated human infection abilities with high mortality rates. Although influenza viral infections are usually diagnosed using viral isolation and serological/molecular analyses, the cost, accessibility, and availability of these methods may limit their utility in various settings. The objective of this study was to develop and optimized a multiplex detection system for most influenza viruses currently infecting humans. METHODS: We developed and optimized a multiplex detection system for most influenza viruses currently infecting humans including two type B (both Victoria lineages and Yamagata lineages), H1N1, H3N2, H5N1, H5N6, and H7N9 using Reverse Transcriptional Loop-mediated Isothermal Amplification (RT-LAMP) technology coupled with a one-pot colorimetric visualization system to facilitate direct determination of results without additional steps. We also evaluated this multiplex RT-LAMP for clinical use using a total of 135 clinical and spiked samples (91 influenza viruses and 44 other human infectious viruses). RESULTS: We achieved rapid detection of seasonal influenza viruses (H1N1, H3N2, and Type B) and avian influenza viruses (H5N1, H5N6, H5N8 and H7N9) within an hour. The assay could detect influenza viruses with high sensitivity (i.e., from 100 to 0.1 viral genome copies), comparable to conventional RT-PCR-based approaches which would typically take several hours and require expensive equipment. This assay was capable of specifically detecting each influenza virus (Type B, H1N1, H3N2, H5N1, H5N6, H5N8 and H7N9) without cross-reactivity with other subtypes of AIVs or other human infectious viruses. Furthermore, 91 clinical and spiked samples confirmed by qRT-PCR were also detected by this multiplex RT-LAMP with 98.9% agreement. It was more sensitive than one-step RT-PCR approach (92.3%). CONCLUSIONS: Results of this study suggest that our multiplex RT-LAMP assay may provide a rapid, sensitive, cost-effective, and reliable diagnostic method for identifying recent influenza viruses infecting humans, especially in locations without access to large platforms or sophisticated equipment.


Assuntos
Colorimetria/métodos , Vírus da Influenza A/genética , Influenza Humana/virologia , Técnicas de Amplificação de Ácido Nucleico/métodos , Reações Cruzadas , Humanos , Vírus da Influenza A Subtipo H1N1/genética , Vírus da Influenza A Subtipo H1N1/isolamento & purificação , Vírus da Influenza A Subtipo H3N2/genética , Vírus da Influenza A Subtipo H3N2/isolamento & purificação , Virus da Influenza A Subtipo H5N1/genética , Subtipo H7N9 do Vírus da Influenza A/genética , Subtipo H7N9 do Vírus da Influenza A/isolamento & purificação , Vírus da Influenza A/isolamento & purificação , Vírus da Influenza A/patogenicidade , Transcrição Reversa
5.
Pan Afr Med J ; 33: 42, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31384357

RESUMO

Introduction: We investigated an outbreak of influenza-like illness (ILI) at a boarding school in Eastern Cape Province, South Africa. We aimed to confirm the etiological agent, estimate attack rates and identify risk factors for illness. Methods: We conducted a retrospective cohort study including senior school boarders (n=308). Students with ILI (cough and fever) were identified through school medical records. We also conducted a questionnaire-based cross-sectional study among senior students including boarders (n=107) and day students (n=45). We collected respiratory specimens for respiratory pathogen testing by real-time polymerase chain reaction from a subset of symptomatic students. We calculated attack rates of medically attended ILI (medILI) and identified factors associated with medILI using logistic regression. We calculated seasonal influenza vaccine effectiveness (VE) against medILI. Results: Influenza A (H3N2) virus was detected in 61% (23/38) of specimens. Attack rate for medILI was 13% among boarders (39/308) in the cohort study and 20% in both day students (9/45) and boarders (21/107) in the cross-sectional study. Playing squash was associated with medILI (aOR 5.35, 95% confidence interval [95% CI]: 1.68-17.07). Of the boarders, 19% (57/308) were vaccinated before the outbreak. The adjusted VE against medILI was 18% (aOR 0.82, 95% CI 0.38-1.78). The outbreak led to cancellation of several events and the need for academic remedial sessions. Conclusion: We confirmed an influenza A (H3N2) virus outbreak with a high attack rate. The outbreak affected academic and sports activities. Participation in sports and social gatherings while experiencing ILI should be discouraged to reduce viral transmission and impact on school activities.


Assuntos
Surtos de Doenças , Vírus da Influenza A Subtipo H3N2/isolamento & purificação , Vacinas contra Influenza/administração & dosagem , Influenza Humana/epidemiologia , Adolescente , Criança , Estudos de Coortes , Estudos Transversais , Feminino , Humanos , Influenza Humana/virologia , Masculino , Estudos Retrospectivos , Fatores de Risco , Instituições Acadêmicas , África do Sul/epidemiologia , Estudantes , Adulto Jovem
6.
Emerg Microbes Infect ; 8(1): 1157-1167, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31373538

RESUMO

The spread of influenza A/H3N2 variants possessing the hemagglutinin 121 K mutation and the unexpectedly high incidence of influenza in the 2017-2018 northern hemisphere influenza season have raised serious concerns about the next pandemic. We summarized the national surveillance data of seasonal influenza in China and identified marked differences in influenza epidemics between northern and southern China, particularly the predominating subtype and the presence of an additional summer peak in southern China. Notably, a minor spring peak of influenza caused by a different virus subtype was also observed. We also revealed that the 3C.2a lineage was dominant from the summer of 2015 to the end of the 2015-2016 peak season in China, after which the 3C.2a2 lineage predominated despite the importation and co-circulation of the 121 K variants of 3C.2a1 and 3C.2a3 lineages at the global level. Finally, an analysis based on genetic distances revealed a delay in A/H3N2 vaccine strain update. Overall, our results highlight the complicated circulation pattern of seasonal influenza in China and the necessity for a timely vaccine strain update worldwide.


Assuntos
Variação Genética , Vírus da Influenza A Subtipo H3N2/classificação , Vírus da Influenza A Subtipo H3N2/genética , Influenza Humana/epidemiologia , Influenza Humana/virologia , China/epidemiologia , Humanos , Incidência , Vírus da Influenza A Subtipo H3N2/isolamento & purificação , Epidemiologia Molecular , Filogeografia
7.
Nat Commun ; 10(1): 3422, 2019 07 31.
Artigo em Inglês | MEDLINE | ID: mdl-31366921

RESUMO

Severe influenza infection has no effective treatment available. One of the key barriers to developing host-directed therapy is a lack of reliable prognostic factors needed to guide such therapy. Here, we use a network analysis approach to identify host factors associated with severe influenza and fatal outcome. In influenza patients with moderate-to-severe diseases, we uncover a complex landscape of immunological pathways, with the main changes occurring in pathways related to circulating neutrophils. Patients with severe disease display excessive neutrophil extracellular traps formation, neutrophil-inflammation and delayed apoptosis, all of which have been associated with fatal outcome in animal models. Excessive neutrophil activation correlates with worsening oxygenation impairment and predicted fatal outcome (AUROC 0.817-0.898). These findings provide new evidence that neutrophil-dominated host response is associated with poor outcomes. Measuring neutrophil-related changes may improve risk stratification and patient selection, a critical first step in developing host-directed immune therapy.


Assuntos
Armadilhas Extracelulares/imunologia , Influenza Humana/imunologia , Influenza Humana/patologia , Ativação de Neutrófilo/imunologia , Neutrófilos/imunologia , Ciclo Celular/imunologia , Feminino , Expressão Gênica/genética , Humanos , Vírus da Influenza A Subtipo H1N1/imunologia , Vírus da Influenza A Subtipo H1N1/isolamento & purificação , Vírus da Influenza A Subtipo H3N2/imunologia , Vírus da Influenza A Subtipo H3N2/isolamento & purificação , Vírus da Influenza B/imunologia , Vírus da Influenza B/isolamento & purificação , Influenza Humana/mortalidade , Pulmão/imunologia , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Respiração Artificial , Insuficiência Respiratória/mortalidade , Insuficiência Respiratória/patologia , Insuficiência Respiratória/virologia
8.
Indian J Med Microbiol ; 37(1): 42-49, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31424009

RESUMO

Introduction: Influenza A(H1N1)pdm09 virus, since its identification in April 2009, has continued to cause significant outbreaks of respiratory tract infections including pandemics in humans. In the course of its evolution, the virus has acquired many mutations with an ability to cause increased disease severity. A regular molecular surveillance of the virus is essential to mark the evolutionary changes that may cause a shift to the viral behavior. Materials and Methods: Samples of Throat/Nasal swabs were collected from a total of 3715 influenza-like illness cases and screened by Real-time Reverse Transcription-Polymerase Chain Reaction for influenza viruses. Nucleotide sequence analysis was done to identify changes in antigenicity of the virus strains. Results: The present study describes the molecular characteristics of influenza A(H1N1)pdm09 viruses detected in Assam of Northeast India during 2009-2015. Influenza A viruses were detected in 11.4% (425/3715), of which influenza A(H1N1)pdm09 viruses were detected in 41.4% (176/425). The nucleotide sequencing of influenza A(H1N1)pdm09 viruses revealed a total of 17 and 22 amino acid substitutions in haemagglutinin (HA) and neuraminidase (NA) genes of the virus, respectively, compared to contemporary vaccine strain A/California/07/2009. The important mutations detected in HA genes of A/Assam(H1N1)pdm09 strains included E391K, K180Q and S202T. Mutation 'N248D' which has an ability to develop oseltamivir resistance was also detected in NA gene of A/Assam(H1N1)pdm09 strains. Conclusions: Regular molecular surveillance of influenza A(H1N1)pdm09 is important to monitor the viral behavior in terms of increase virulence, drug resistance pattern and emergence of novel strains.


Assuntos
Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Vírus da Influenza A Subtipo H1N1/genética , Vírus da Influenza A Subtipo H3N2/genética , Influenza Humana/epidemiologia , Neuraminidase/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Antivirais/farmacologia , Sequência de Bases , Criança , Pré-Escolar , Feminino , Variação Genética/genética , Humanos , Índia/epidemiologia , Lactente , Vírus da Influenza A Subtipo H1N1/efeitos dos fármacos , Vírus da Influenza A Subtipo H1N1/isolamento & purificação , Vírus da Influenza A Subtipo H3N2/isolamento & purificação , Influenza Humana/tratamento farmacológico , Influenza Humana/virologia , Masculino , Pessoa de Meia-Idade , Oseltamivir/farmacologia , Filogenia , RNA Viral/genética , Reação em Cadeia da Polimerase em Tempo Real , Análise de Sequência de RNA , Adulto Jovem
9.
Zhonghua Jie He He Hu Xi Za Zhi ; 42(7): 510-514, 2019 Jul 12.
Artigo em Chinês | MEDLINE | ID: mdl-31365967

RESUMO

Objective: To investigate the clinical and epidemiological characteristics of influenza A (H3N2) infected patients in Jinhua area, and therefore to improve the understanding of infection with H3N2 influenza virus. Methods: The pharynx swab specimens for pathogenic detection were collected from acute respiratory infection (ARI) cases in the fever clinic of the sentinel hospital in Jinhua area from 2014 to 2017. Descriptive statistics method was used to analyze the clinical features and pathogenics characteristics of the patients infected with H3N2 influenza virus. The t test or χ(2) test of independent samples were used for comparison between groups. Results: A total of 3 803 cases of acute respiratory infection (ARI) were reported in the sentinel hospital in Jinhua area from 2014 to 2017. Among them, 245 cases (6.4%) of H3N2 influenza were diagnosed, including 153 males (62.4%) and 92 females (37.6%), aged from 0.5 to 95 years, with an average age of (50.1+15.7) years. They were divided into 5 age groups, with 107 (43.7%) patients aged 60 years and older. The incidence of major diseases was 43.7%. There was no significant difference in the gender in different age groups (χ(2)=4.581, P=0.333). The seasonal peak of H3N2 influenza A virus infection was mainly in summer (In June-September), but was also seen in other months. In the 4 years from 2014 to 2017, there were a total of 4 peaks, which occurred in July-September, July-August, June-August, and June-August. The body temperature of most patients (73.1%) was between 38.0 and 38.9 ℃. The main positive signs of H3N2 influenza A virus infection were different degrees of pharyngeal hyperemia and tonsillar enlargement. Fever (>38 ℃), cough, dizziness, fatigue, sore throat, headache, chills, shortness of breath, runny nose, myalgia, expectoration, nasal congestion were the main symptoms of H3N2 cases. The proportion of abnormal X-ray/CT manifestations in H3N2 influenza A virus infection cases was lower than that of other influenza viruses. 89.8% of the patients were positive for H3N2 influenza A. The average lymphocyte count was (1.1±0.5) × 10(9)/L, total platelet count (157±39) × 10(9)/L in H3N2 influenza A infection group, which were lower than those in other influenza positive patients [(1.2±0.6)×10(9)/L and (165±42) × 10(9)/L], while the neutrophil count (3.6±0.8) × 10(9)/L was higher than that in other influenza positive patients (3.4±1.0) × 10(9)/L(all P<0.05). Conclusions: Patients with H3N2 influenza A in Jinhua mostly presented with throat congestion and tonsillar enlargement in varying degrees, fever (>38 ℃), cough and sputum production. The seasonal peak of influenza A was in summer (June-September). Elderly aged 60 years or older were the susceptible group.


Assuntos
Vírus da Influenza A Subtipo H3N2 , Influenza Humana/epidemiologia , Infecções Respiratórias/epidemiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Tosse/etiologia , Feminino , Febre/etiologia , Humanos , Lactente , Vírus da Influenza A Subtipo H3N2/isolamento & purificação , Influenza Humana/diagnóstico , Masculino , Pessoa de Meia-Idade , Infecções Respiratórias/diagnóstico , Estações do Ano , Adulto Jovem
10.
Emerg Microbes Infect ; 8(1): 1017-1026, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31287780

RESUMO

Host switch events of influenza A viruses (IAVs) continuously pose a zoonotic threat to humans. In 2013, swine-origin H1N1 IAVs emerged in dogs soon after they were detected in swine in the Guangxi province of China. This host switch was followed by multiple reassortment events between these H1N1 and previously circulating H3N2 canine IAVs (IAVs-C) in dogs. To evaluate the phenotype of these newly identified viruses, we characterized three swine-origin H1N1 IAVs-C and one reassortant H1N1 IAV-C. We found that H1N1 IAVs-C predominantly bound to human-type receptors, efficiently transmitted via direct contact in guinea pigs and replicated in human lung cells. Moreover, the swine-origin H1N1 IAVs-C were lethal in mice and were transmissible by respiratory droplets in guinea pigs. Importantly, sporadic human infections with these viruses have been detected, and preexisting immunity in humans might not be sufficient to prevent infections with these new viruses. Our results show the potential of H1N1 IAVs-C to infect and transmit in humans, suggesting that these viruses should be closely monitored in the future.


Assuntos
Doenças do Cão/virologia , Vírus da Influenza A Subtipo H1N1/isolamento & purificação , Infecções por Orthomyxoviridae/veterinária , Doenças dos Suínos/virologia , Animais , China , Doenças do Cão/mortalidade , Cães , Feminino , Cobaias , Humanos , Vírus da Influenza A Subtipo H1N1/classificação , Vírus da Influenza A Subtipo H1N1/genética , Vírus da Influenza A Subtipo H1N1/patogenicidade , Vírus da Influenza A Subtipo H3N2/classificação , Vírus da Influenza A Subtipo H3N2/genética , Vírus da Influenza A Subtipo H3N2/isolamento & purificação , Influenza Humana/mortalidade , Influenza Humana/virologia , Camundongos , Camundongos Endogâmicos BALB C , Infecções por Orthomyxoviridae/mortalidade , Infecções por Orthomyxoviridae/virologia , Vírus Reordenados/classificação , Vírus Reordenados/genética , Vírus Reordenados/isolamento & purificação , Vírus Reordenados/patogenicidade , Suínos , Doenças dos Suínos/mortalidade , Virulência
11.
BMC Infect Dis ; 19(1): 668, 2019 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-31357951

RESUMO

BACKGROUND: A severe seasonal influenza epidemic was observed during 2017-2018 in China, prompting questions on clinical characteristics and outcomes of severe cases with influenza. METHODS: We retrospectively collected clinical data and outcomes of laboratory-confirmed hospitalized patients (severe to critical) during Jan-2011 to Feb-2018 from five hospitals, followed by a systematic analysis of cases from 2017 to 2018 (n = 289) and all previous epidemics during 2011-2017 (n = 169). RESULTS: In-hospital fatality was over 5-folds higher during the 2017-2018 (p < 0.01) in which 19 patients died (6.6%), whereas only 2 mortalities (1.2%) were observed during 2011-2017. Of the 289 hospitalized in 2017-2018, 153 were confirmed with influenza B virus, 110 with A/H1N1pdm09, and 26 A/H3N2, whereas A/H1N1pdm09 was the predominant cause of hospitalization in previous seasons combined (45%). Fatal cases in 2017-2018 were exclusively associated with either influenza B or A/H1N1pdm09. Our results show that a significant lower proportion of patients aged 14 or greater were treated with oseltamivir, during the 2017-2018 epidemic, and exhibited higher levels of clinical severity. CONCLUSIONS: In-hospital fatality rate might be significantly higher in the 2017-2018 season in China. A sufficient supply of oseltamivir and antiviral therapy within 48 h from onset could reduce fatality rates.


Assuntos
Antivirais/uso terapêutico , Epidemias , Vírus da Influenza A Subtipo H1N1/isolamento & purificação , Vírus da Influenza A Subtipo H3N2/isolamento & purificação , Vírus da Influenza B/isolamento & purificação , Influenza Humana/epidemiologia , Oseltamivir/uso terapêutico , Adolescente , Adulto , China/epidemiologia , Feminino , Hospitalização , Humanos , Influenza Humana/mortalidade , Influenza Humana/virologia , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Adulto Jovem
12.
MMWR Morb Mortal Wkly Rep ; 68(24): 544-551, 2019 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-31220057

RESUMO

Influenza activity* in the United States during the 2018-19 season (September 30, 2018-May 18, 2019) was of moderate severity (1). Nationally, influenza-like illness (ILI)† activity began increasing in November, peaked during mid-February, and returned to below baseline in mid-April; the season lasted 21 weeks,§ making it the longest season in 10 years. Illness attributed to influenza A viruses predominated, with very little influenza B activity. Two waves of influenza A were notable during this extended season: influenza A(H1N1)pdm09 viruses from October 2018 to mid-February 2019 and influenza A(H3N2) viruses from February through May 2019. Compared with the 2017-18 influenza season, rates of hospitalization this season were lower for adults, but were similar for children. Although influenza activity is currently below surveillance baselines, testing for seasonal influenza viruses and monitoring for novel influenza A virus infections should continue year-round. Receiving a seasonal influenza vaccine each year remains the best way to protect against seasonal influenza and its potentially severe consequences.


Assuntos
Vírus da Influenza A Subtipo H1N1/isolamento & purificação , Vírus da Influenza A Subtipo H3N2/isolamento & purificação , Vírus da Influenza B/isolamento & purificação , Influenza Humana/epidemiologia , Vigilância da População , Adolescente , Adulto , Idoso , Antivirais/farmacologia , Criança , Mortalidade da Criança , Pré-Escolar , Efeitos Psicossociais da Doença , Farmacorresistência Viral , Hospitalização/estatística & dados numéricos , Humanos , Lactente , Mortalidade Infantil , Recém-Nascido , Vírus da Influenza A Subtipo H1N1/efeitos dos fármacos , Vírus da Influenza A Subtipo H1N1/genética , Vírus da Influenza A Subtipo H3N2/efeitos dos fármacos , Vírus da Influenza A Subtipo H3N2/genética , Vírus da Influenza B/efeitos dos fármacos , Vírus da Influenza B/genética , Vacinas contra Influenza/administração & dosagem , Vacinas contra Influenza/química , Influenza Humana/mortalidade , Influenza Humana/prevenção & controle , Influenza Humana/virologia , Pessoa de Meia-Idade , Pacientes Ambulatoriais/estatística & dados numéricos , Pneumonia/mortalidade , Estações do Ano , Índice de Gravidade de Doença , Estados Unidos/epidemiologia , Adulto Jovem
13.
J Coll Physicians Surg Pak ; 29(5): 459-462, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31036119

RESUMO

OBJECTIVE: To determine the frequency of infections caused by Influenza viruses, i.e. Influenza A (H1N1) pdm09, Influenza A (H3N2) and Influenza B in patients presenting with respiratory tract infections, i.e. influenza-like illness (ILI) and severe acute respiratory illness (SARI). STUDY DESIGN: Descriptive, cross-sectional study. PLACE AND DURATION OF STUDY: Department of Virology, Armed Forces Institute of Pathology (AFIP), Rawalpindi, from October 2017 to February 2018. METHODOLOGY: A total of 624 samples from patients with respiratory tract infections (both ILI and SARI) were included in the study. Specimens collected from the patients included nasal swabs and throat swabs, which were transported in viral transport medium (VTM) to Virology Department, AFIP. Multiplex PCR was done for Influenza A (H1N1) pdm09, Influenza A (H3N2) and Influenza B. RESULTS: A total of 200 (32%) samples were found to be positive for Influenza viruses. Out of total 624 samples analysed, 220 (35.3%) were from females and 404 (64.7%) from males. Among these, 510 (81.7%) presented with ILI and 114 (18.3%) with SARI. Among positive samples, 120 (19.2%) samples were positive for H1N1, 61 (9.8%) for H3N2 and 19 (3%) were positive for Influenza B. Highest number of positive cases occurred in the month of January, i.e. 148 (74%) cases. Only 3 (2.5%) patients out of 120 infected with H1N1 were in age group-I (0-5 years). While in age group-II (6-30 years), age group-III (31-60 years), and age group-IV (>60 years); 39 (32.5%), 63 (52.5%) and 15 (12.5%) patients were infected by H1N1, respectively. Maximum patients with H3N2 infection were in age group-III; 30 (49.2%) of the total 61. Commonest Influenza subtype in age group-IV was H3N2 found in 20 (32.8%) patients, followed by H1N1 in 15 (12.5%) patients. CONCLUSION: The dominant subtype in our set-up, during winter of 2017-2018, was Influenza A (H1N1) pdm09. Highest numbers of positive cases were recorded in the month of January. People with ILI and SARI should be tested for Influenza viruses to avoid unnecessary use of antibiotics.


Assuntos
Vírus da Influenza A Subtipo H1N1/genética , Vírus da Influenza A Subtipo H3N2/genética , Vírus da Influenza B/genética , Influenza Humana/diagnóstico , Reação em Cadeia da Polimerase Multiplex/métodos , Infecções Respiratórias/diagnóstico , Síndrome Respiratória Aguda Grave/diagnóstico , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Estudos Transversais , Feminino , Humanos , Lactente , Recém-Nascido , Vírus da Influenza A Subtipo H1N1/isolamento & purificação , Vírus da Influenza A Subtipo H3N2/isolamento & purificação , Vírus da Influenza B/isolamento & purificação , Influenza Humana/epidemiologia , Influenza Humana/virologia , Masculino , Pessoa de Meia-Idade , Infecções Respiratórias/epidemiologia , Infecções Respiratórias/virologia , Estações do Ano , Síndrome Respiratória Aguda Grave/epidemiologia , Síndrome Respiratória Aguda Grave/virologia , Adulto Jovem
14.
Nat Microbiol ; 4(8): 1268-1273, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31036910

RESUMO

Here, we developed hCK, a Madin-Darby canine kidney (MDCK) cell line that expresses high levels of human influenza virus receptors and low levels of avian virus receptors. hCK cells supported human A/H3N2 influenza virus isolation and growth much more effectively than conventional MDCK or human virus receptor-overexpressing (AX4) cells. A/H3N2 viruses propagated in hCK cells also maintained higher genetic stability than those propagated in MDCK and AX4 cells.


Assuntos
Células Madin Darby de Rim Canino/virologia , Orthomyxoviridae/genética , Orthomyxoviridae/isolamento & purificação , Animais , Antígenos CD/metabolismo , Linhagem Celular , Cães , Humanos , Vírus da Influenza A Subtipo H3N2/genética , Vírus da Influenza A Subtipo H3N2/crescimento & desenvolvimento , Vírus da Influenza A Subtipo H3N2/isolamento & purificação , Influenza Humana , Mutação , Receptores Virais/genética , Receptores Virais/metabolismo , Sialiltransferases/genética , Sialiltransferases/metabolismo
15.
BMC Infect Dis ; 19(1): 415, 2019 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-31088481

RESUMO

BACKGROUND: The Global Influenza Hospital Surveillance Network is an international platform whose primary objective is to study severe cases of influenza requiring hospitalization. METHODS: During the 2015-2016 influenza season, 11 sites in the Global Influenza Hospital Surveillance Network in nine countries (Russian Federation, Czech Republic, Turkey, France, China, Spain, Mexico, India, and Brazil) participated in a prospective, active-surveillance, hospital-based epidemiological study. Influenza infection was confirmed by reverse transcription-polymerase chain reaction. Influenza vaccine effectiveness (IVE) against laboratory-confirmed influenza was estimated using a test-negative approach. RESULTS: 9882 patients with laboratory results were included of which 2415 (24.4%) were positive for influenza, including 1415 (14.3%) for A(H1N1)pdm09, 235 (2.4%) for A(H3N2), 180 (1.8%) for A not subtyped, 45 (0.5%) for B/Yamagata-lineage, 532 (5.4%) for B/Victoria-lineage, and 33 (0.3%) for B not subtyped. Of included admissions, 39% were < 5 years of age and 67% had no underlying conditions. The odds of being admitted with influenza were higher among pregnant than non-pregnant women (odds ratio, 2.82 [95% confidence interval (CI), 1.90 to 4.19]). Adjusted IVE against influenza-related hospitalization was 16.3% (95% CI, 0.4 to 29.7). Among patients targeted for influenza vaccination, adjusted IVE against hospital admission with influenza was 16.2% (95% CI, - 3.6 to 32.2) overall, 23.0% (95% CI, - 3.3 to 42.6) against A(H1N1)pdm09, and - 25.6% (95% CI, - 86.3 to 15.4) against B/Victoria lineage. CONCLUSIONS: The 2015-2016 influenza season was dominated by A(H1N1)pdm09 and B/Victoria-lineage. Hospitalization with influenza often occurred in healthy and young individuals, and pregnant women were at increased risk of influenza-related hospitalization. Influenza vaccines provided low to moderate protection against hospitalization with influenza and no protection against the predominant circulating B lineage, highlighting the need for more effective and broader influenza vaccines.


Assuntos
Vacinas contra Influenza/imunologia , Influenza Humana/diagnóstico , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Feminino , Hospitalização/estatística & dados numéricos , Humanos , Vírus da Influenza A Subtipo H1N1/isolamento & purificação , Vírus da Influenza A Subtipo H3N2/isolamento & purificação , Influenza Humana/epidemiologia , Influenza Humana/prevenção & controle , Masculino , Pessoa de Meia-Idade , Razão de Chances , Gravidez , Estudos Prospectivos , Estações do Ano , Resultado do Tratamento , Adulto Jovem
16.
PLoS One ; 14(4): e0216247, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31022287

RESUMO

Highly sensitive and rapid technology of surface enhanced Raman scattering (SERS) was applied to create aptasensors for influenza virus detection. SERS achieves 106-109 times signal amplification, yielding excellent sensitivity, whereas aptamers to hemagglutinin provide a specific recognition of the influenza virus. Aptamer RHA0385 was demonstrated to have essentially broad strain-specificity toward both recombinant hemagglutinins and the whole viruses. To achieve high sensitivity, a sandwich of primary aptamers, influenza virus and secondary aptamers was assembled. Primary aptamers were attached to metal particles of a SERS substrate, and influenza viruses were captured and bound with secondary aptamers labelled with Raman-active molecules. The signal was affected by the concentration of both primary and secondary aptamers. The limit of detection was as low as 1 · 10-4 hemagglutination units per probe as tested for the H3N2 virus (A/England/42/72). Aptamer-based sensors provided recognition of various influenza viral strains, including H1, H3, and H5 hemagglutinin subtypes. Therefore, the aptasensors could be applied for fast and low-cost strain-independent determination of influenza viruses.


Assuntos
Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais/métodos , Vírus da Influenza A Subtipo H3N2/isolamento & purificação , Análise Espectral Raman , Ressonância de Plasmônio de Superfície
17.
Nat Commun ; 10(1): 1660, 2019 04 10.
Artigo em Inglês | MEDLINE | ID: mdl-30971703

RESUMO

Influenza A viruses evolve rapidly to escape host immunity, causing reinfection. The form and duration of protection after each influenza virus infection are poorly understood. We quantify the dynamics of protective immunity by fitting individual-level mechanistic models to longitudinal serology from children and adults. We find that most protection in children but not adults correlates with antibody titers to the hemagglutinin surface protein. Protection against circulating strains wanes to half of peak levels 3.5-7 years after infection in both age groups, and wanes faster against influenza A(H3N2) than A(H1N1)pdm09. Protection against H3N2 lasts longer in adults than in children. Our results suggest that influenza antibody responses shift focus with age from the mutable hemagglutinin head to other epitopes, consistent with the theory of original antigenic sin, and might affect protection. Imprinting, or primary infection with a subtype, has modest to no effect on the risk of non-medically attended infections in adults.


Assuntos
Anticorpos Antivirais/sangue , Proteção Cruzada/imunologia , Memória Imunológica/imunologia , Influenza Humana/imunologia , Modelos Biológicos , Adolescente , Adulto , Fatores Etários , Idoso , Anticorpos Antivirais/imunologia , Antígenos Virais/imunologia , Antígenos Virais/isolamento & purificação , Criança , Pré-Escolar , Feminino , Seguimentos , Hemaglutininas/imunologia , Hong Kong/epidemiologia , Humanos , Incidência , Vírus da Influenza A Subtipo H1N1/imunologia , Vírus da Influenza A Subtipo H1N1/isolamento & purificação , Vírus da Influenza A Subtipo H3N2/imunologia , Vírus da Influenza A Subtipo H3N2/isolamento & purificação , Vacinas contra Influenza/administração & dosagem , Vacinas contra Influenza/imunologia , Influenza Humana/epidemiologia , Influenza Humana/prevenção & controle , Influenza Humana/virologia , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Ensaios Clínicos Controlados Aleatórios como Assunto , Fatores de Tempo , Adulto Jovem
18.
BMC Infect Dis ; 19(1): 308, 2019 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-30947693

RESUMO

BACKGROUND: Despite World Health Organization recommendations, in many countries young children are not targeted for influenza vaccination. To help inform influenza vaccination policy, we examined the occurrence and burden of influenza in healthy children aged 6 to 35 months using data from a recent phase III placebo-controlled influenza vaccine trial conducted in countries in the Northern and Southern Hemispheres. METHODS: This was an analysis of data from participants included in the placebo arm of a phase III clinical trial in healthy children aged 6 to 35 months (EudraCT no. 2013-001231-51). Included children had never been vaccinated for influenza and were observed for one influenza season. Outcome measures included the occurrence of influenza-like illness (ILI), laboratory-confirmed influenza, virus types/subtypes, severe symptoms and complications of confirmed influenza, and healthcare use associated with confirmed influenza. RESULTS: Data from 2210 participants were analysed. ILI was reported for 811 participants (36.7%). Of these, 255 participants (31.4%) had 263 virologically confirmed episodes of influenza. The overall influenza attack rate was 11.5%. The most common influenza virus detected was A(H3N2) (40.7%), followed by B/Yamagata (23.6%), A(H1N1) (18.6%), and B/Victoria (8.0%). Grade 3 fever was reported in 24.3% of confirmed episodes, acute lower respiratory infection in 8.7%, acute otitis media in 6.1%, and pneumonia in 1.9%. In most influenza episodes (93.2%), antipyretics, analgesics, or non-steroidal anti-inflammatory drugs were taken. Antibiotics were prescribed for 41.4% of influenza episodes. More than half of the influenza episodes (57.0%) resulted in outpatient visits. Influenza resulted in overnight hospitalisation in 1.1% of episodes. CONCLUSIONS: Influenza is associated with a significant burden of disease in healthy children. This analysis also revealed that antibiotics continue to be frequently used for young children with influenza. TRIAL REGISTRATION: EudraCT no. 2013-001231-51 .


Assuntos
Influenza Humana/epidemiologia , Antibacterianos/uso terapêutico , Antipiréticos/uso terapêutico , Pré-Escolar , Efeitos Psicossociais da Doença , Feminino , Humanos , Lactente , Vírus da Influenza A Subtipo H1N1/genética , Vírus da Influenza A Subtipo H1N1/isolamento & purificação , Vírus da Influenza A Subtipo H3N2/genética , Vírus da Influenza A Subtipo H3N2/isolamento & purificação , Vacinas contra Influenza/imunologia , Influenza Humana/economia , Influenza Humana/patologia , Influenza Humana/virologia , Masculino , Efeito Placebo , RNA Viral/genética , RNA Viral/metabolismo , Infecções Respiratórias/diagnóstico , Infecções Respiratórias/tratamento farmacológico , Infecções Respiratórias/epidemiologia , Índice de Gravidade de Doença
19.
PLoS One ; 14(4): e0214207, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30951544

RESUMO

Respiratory diseases are a major contributor to morbidity and mortality in many tropical countries, including Lao PDR. However, little has been published regarding viral or bacterial pathogens that can contribute to influenza-like illness (ILI) in a community setting. We report on the results of a community-based surveillance that prospectively monitored the incidence of ILI and its causative pathogens in Vientiane capital in Lao PDR. A cohort of 995 households, including 4885 study participants, were followed-up between May 2015 and May 2016. Nasopharyngeal swabs, throat swabs, and sputum specimens were collected from ILI cases identified through active case-finding. Real-Time PCR was used to test nasopharyngeal swabs for 21 respiratory pathogens, while throat and sputum samples were subjected to bacterial culture. Generalized linear mixed models were used to assess potential risk factors for associations with ILI. In total, 548 episodes of ILI were reported among 476 (9.7%) of the study participants and 330 (33.2%) of the study households. The adjusted estimated incidence of ILI within the study area was 10.7 (95%CI: 9.4-11.9) episodes per 100 person-years. ILI was significantly associated with age group (p<0.001), sex (p<0.001), and number of bedrooms (p = 0.04) in multivariate analysis. In 548 nasopharyngeal swabs, the most commonly detected potential pathogens were Streptococcus pneumoniae (17.0%), Staphylococcus aureus (11.3%), influenza A (11.1%; mostly subtype H3N2), rhinovirus (7.5%), and influenza B (8.0%). Streptococci were isolated from 42 (8.6%) of 536 throat swabs, most (27) of which were Lancefield Group G. Co-infections were observed in 132 (24.1%) of the 548 ILI episodes. Our study generated valuable data on respiratory disease burden and patterns of etiologies associated with community-acquired acute respiratory illness Laos. Establishment of a surveillance strategy in Laos to monitor trends in the epidemiology and burden of acute respiratory infections is required to minimize their impact on human health.


Assuntos
Vírus da Influenza A Subtipo H3N2/patogenicidade , Influenza Humana/epidemiologia , Infecções Respiratórias/epidemiologia , Rhinovirus/patogenicidade , Adolescente , Adulto , Criança , Pré-Escolar , Estudos de Coortes , Características da Família , Feminino , Humanos , Lactente , Vírus da Influenza A Subtipo H3N2/isolamento & purificação , Influenza Humana/diagnóstico , Influenza Humana/patologia , Influenza Humana/virologia , Laos/epidemiologia , Masculino , Pessoa de Meia-Idade , Faringe/patologia , Faringe/virologia , Reação em Cadeia da Polimerase em Tempo Real , Infecções Respiratórias/diagnóstico , Infecções Respiratórias/patologia , Infecções Respiratórias/virologia
20.
BMC Infect Dis ; 19(1): 224, 2019 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-30832611

RESUMO

BACKGROUND: Total four influenza pandemics have happened since twentieth century, and currently influenza is in the seasonal epidemic around the world, with a sharp increase in its incidence each year. As an effective treatment of influenza infection, the use of oseltamivir is climbing globally. However, there have been reports of neuropsychiatric events associated with the drug, mainly in young patients and males. To our knowledge, this is the first reported case of oseltamivir-associated neuropsychiatric events occurring in an patient over 50-year-old. CASE PRESENTATION: Here we present the case of a 57-year-old Chinese female with H3N2 influenza infection who developed abnormal psychiatric symptoms after administration of high doses of oseltamivir. The patient recovered completely within the cessation of oseltamivir. CONCLUSIONS: We hope that our case report will lead clinicians to be mindful about oseltamivir's potential neuropsychiatric side effects, and to pay special attention to each patient's mental state, both in children and adults.


Assuntos
Antivirais/efeitos adversos , Influenza Humana/tratamento farmacológico , Transtornos Mentais/etiologia , Oseltamivir/efeitos adversos , Antivirais/uso terapêutico , Feminino , Humanos , Vírus da Influenza A Subtipo H3N2/genética , Vírus da Influenza A Subtipo H3N2/isolamento & purificação , Influenza Humana/virologia , Pessoa de Meia-Idade , Oseltamivir/uso terapêutico , RNA Viral/genética , RNA Viral/metabolismo , Resultado do Tratamento
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