scholarly journals Epidemiology of seasonal influenza in Bangkok between 2009 and 2012

2013 ◽  
Vol 7 (10) ◽  
pp. 734-740 ◽  
Author(s):  
Slinporn Prachayangprecha ◽  
Jarika Makkoch ◽  
Kamol Suwannakarn ◽  
Preeyaporn Vichaiwattana ◽  
Sumeth Korkong ◽  
...  
Keyword(s):  
Rainy Season ◽  
Influenza A ◽  
Seasonal Influenza ◽  
Seasonal Pattern ◽  
Laboratory Data ◽  
Influenza Virus Infection ◽  
Influenza Viruses ◽  
Influenza B ◽  
Rainy Period ◽  
Influenza Activity

Introduction: This study investigated influenza activity in Bangkok, Thailand between June 2009 and July 2012. Methodology: Real-time reverse transcription polymerase chain reaction (RT-PCR) was performed to detect influenza viruses among patients with influenza-like illnesses. Results: Of the 6417 patients tested, influenza virus infection was detected in 42% (n = 2697) of the specimens. Influenza A pH1N1 viruses comprised the predominant strain between 2009 and 2010, and seasonal influenza (H3) had a high prevalence in 2011. Laboratory data showed a prevalence and seasonal pattern of influenza viruses. In 2009, influenza activity peaked in July, the rainy season. In 2010, influenza activity happened in two phases, with the initial one at the beginning of the year and another peak between June and August 2010, which again corresponded to the rainy period. Influenza activity was low for several consecutive weeks at the beginning of 2011, and high H3N2 activity was recorded during the rainy season between July and September 2011. However, from the beginning of 2012 through July 2012, pH1N1, influenza H3N2, and influenza B viruses continuously circulated at a very low level. Conclusion: The seasonal pattern of influenza activity in Thailand tended to peak during rainy season between July and September.

scholarly journals National influenza mid-season report, 2020–2021

2021 ◽  
Vol 47 (1) ◽  
pp. 1-4
Author(s):  
Lisa Lee ◽  
Kelly Butt ◽  
Steven Buckrell ◽  
Andrea Nwosu ◽  
Claire Sevenhuysen ◽  
...  
Keyword(s):  
Influenza A ◽  
Seasonal Influenza ◽  
Influenza Season ◽  
Influenza Viruses ◽  
Resistance Testing ◽  
Influenza Surveillance ◽  
Influenza B ◽  
Strain Characterization ◽  
Influenza Activity ◽  
Low Levels

Canada's national influenza season typically starts in the latter half of November (week 47) and is defined as the week when at least 5% of influenza tests are positive and a minimum of 15 positive tests are observed. As of December 12, 2020 (week 50), the 2020-2021 influenza season had not begun. Only 47 laboratory-confirmed influenza detections were reported from August 23 to December 12, 2020; an unprecedentedly low number, despite higher than usual levels of influenza testing. Of this small number of detections, 64% were influenza A and 36% were influenza B. Influenza activity in Canada was at historically low levels compared with the previous five seasons. Provinces and territories reported no influenza-associated adult hospitalizations. Fewer than five hospitalizations were reported by the paediatric sentinel hospitalization network. With little influenza circulating, the National Microbiology Laboratory had not yet received samples of influenza viruses collected during the 2020-2021 season for strain characterization or antiviral resistance testing. The assessment of influenza vaccine effectiveness, typically available in mid-March, is expected to be similarly limited if low seasonal influenza circulation persists. Nevertheless, Canada's influenza surveillance system remains robust and has pivoted its syndromic, virologic and severe outcomes system components to support coronavirus disease 2019 (COVID-19) surveillance. Despite the COVID-19 pandemic, the threat of influenza epidemics and pandemics persists. It is imperative 1) to maintain surveillance of influenza, 2) to remain alert to unusual or unexpected events and 3) to be prepared to mitigate influenza epidemics when they resurge.

scholarly journals Molecular Characterization of Seasonal Influenza A and B from Hospitalized Patients in Thailand in 2018–2019

Viruses ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 977
Author(s):  
Kobporn Boonnak ◽  
Chayasin Mansanguan ◽  
Dennis Schuerch ◽  
Usa Boonyuen ◽  
Hatairat Lerdsamran ◽  
...  
Keyword(s):  
Amino Acid ◽  
Influenza A ◽  
Seasonal Influenza ◽  
Influenza Viruses ◽  
Surface Proteins ◽  
Antigenic Drift ◽  
Influenza B ◽  
Receptor Binding Site ◽  
Antigenic Sites ◽  
Ha Protein

Influenza viruses continue to be a major public health threat due to the possible emergence of more virulent influenza virus strains resulting from dynamic changes in virus adaptability, consequent of functional mutations and antigenic drift in surface proteins, especially hemagglutinin (HA) and neuraminidase (NA). In this study, we describe the genetic and evolutionary characteristics of H1N1, H3N2, and influenza B strains detected in severe cases of seasonal influenza in Thailand from 2018 to 2019. We genetically characterized seven A/H1N1 isolates, seven A/H3N2 isolates, and six influenza B isolates. Five of the seven A/H1N1 viruses were found to belong to clade 6B.1 and were antigenically similar to A/Switzerland/3330/2017 (H1N1), whereas two isolates belonged to clade 6B.1A1 and clustered with A/Brisbane/02/2018 (H1N1). Interestingly, we observed additional mutations at antigenic sites (S91R, S181T, T202I) as well as a unique mutation at a receptor binding site (S200P). Three-dimensional (3D) protein structure analysis of hemagglutinin protein reveals that this unique mutation may lead to the altered binding of the HA protein to a sialic acid receptor. A/H3N2 isolates were found to belong to clade 3C.2a2 and 3C.2a1b, clustering with A/Switzerland/8060/2017 (H3N2) and A/South Australia/34/2019 (H3N2), respectively. Amino acid sequence analysis revealed 10 mutations at antigenic sites including T144A/I, T151K, Q213R, S214P, T176K, D69N, Q277R, N137K, N187K, and E78K/G. All influenza B isolates in this study belong to the Victoria lineage. Five out of six isolates belong to clade 1A3-DEL, which relate closely to B/Washington/02/2009, with one isolate lacking the three amino acid deletion on the HA segment at position K162, N163, and D164. In comparison to the B/Colorado/06/2017, which is the representative of influenza B Victoria lineage vaccine strain, these substitutions include G129D, G133R, K136E, and V180R for HA protein. Importantly, the susceptibility to oseltamivir of influenza B isolates, but not A/H1N1 and A/H3N2 isolates, were reduced as assessed by the phenotypic assay. This study demonstrates the importance of monitoring genetic variation in influenza viruses regarding how acquired mutations could be associated with an improved adaptability for efficient transmission.

scholarly journals Phase III Randomized, Double-Blind Study Comparing Single-Dose Intravenous Peramivir with Oral Oseltamivir in Patients with Seasonal Influenza Virus Infection

2011 ◽  
Vol 55 (11) ◽  
pp. 5267-5276 ◽  
Author(s):  
Shigeru Kohno ◽  
Muh-Yong Yen ◽  
Hee-Jin Cheong ◽  
Nobuo Hirotsu ◽  
Tadashi Ishida ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Virus Infection ◽  
Influenza A ◽  
Seasonal Influenza ◽  
Influenza Virus Infection ◽  
Influenza Viruses ◽  
Phase Iii ◽  
Controlled Study ◽  
Double Blind Study ◽  
Double Blind

ABSTRACTAntiviral medications with activity against influenza viruses are important in controlling influenza. We compared intravenous peramivir, a potent neuraminidase inhibitor, with oseltamivir in patients with seasonal influenza virus infection. In a multinational, multicenter, double-blind, double-dummy randomized controlled study, patients aged ≥20 years with influenza A or B virus infection were randomly assigned to receive either a single intravenous infusion of peramivir (300 or 600 mg) or oral administration of oseltamivir (75 mg twice a day [b.i.d.] for 5 days). To demonstrate the noninferiority of peramivir in reducing the time to alleviation of influenza symptoms with hazard model analysis and a noninferiority margin of 0.170, we planned to recruit 1,050 patients in South Korea, Japan, and Taiwan. A total of 1,091 patients (364 receiving 300 mg and 362 receiving 600 mg of peramivir; 365 receiving oseltamivir) were included in the intent-to-treat infected population. The median durations of influenza symptoms were 78.0, 81.0, and 81.8 h in the groups treated with 300 mg of peramivir, 600 mg of peramivir, and oseltamivir, respectively. The hazard ratios of the 300- and 600-mg-peramivir groups compared to the oseltamivir group were 0.946 (97.5% confidence interval [CI], 0.793, 1.129) and 0.970 (97.5% CI, 0.814, 1.157), respectively. Both peramivir groups were noninferior to the oseltamivir group (97.5% CI, <1.170). The overall incidence of adverse drug reactions was significantly lower in the 300-mg-peramivir group, but the incidence of severe reactions in either peramivir group was not different from that in the oseltamivir group. Thus, a single intravenous dose of peramivir may be an alternative to a 5-day oral dose of oseltamivir for patients with seasonal influenza virus infection.

scholarly journals Bacterial Sinusitis and Otitis Media following Influenza Virus Infection in Ferrets

2006 ◽  
Vol 74 (5) ◽  
pp. 2562-2567 ◽  
Author(s):  
Ville T. Peltola ◽  
Kelli L. Boyd ◽  
Julie L. McAuley ◽  
Jerold E. Rehg ◽  
Jonathan A. McCullers
Keyword(s):  
Influenza Virus ◽  
Otitis Media ◽  
Influenza A ◽  
Bacterial Colonization ◽  
Influenza Virus Infection ◽  
Influenza Viruses ◽  
Influenza B Virus ◽  
Influenza B ◽  
Complication Rates ◽  
Pneumococcal Infections

ABSTRACT Streptococcus pneumoniae is the leading cause of otitis media, sinusitis, and pneumonia. Many of these infections result from antecedent influenza virus infections. In this study we sought to determine whether the frequency and character of secondary pneumococcal infections differed depending on the strain of influenza virus that preceded bacterial challenge. In young ferrets infected with influenza virus and then challenged with pneumococcus, influenza viruses of any subtype increased bacterial colonization of the nasopharynx. Nine out of 10 ferrets infected with H3N2 subtype influenza A viruses developed either sinusitis or otitis media, while only 1 out of 11 ferrets infected with either an H1N1 influenza A virus or an influenza B virus did so. These data may partially explain why bacterial complication rates are higher during seasons when H3N2 viruses predominate. This animal model will be useful for further study of the mechanisms that underlie viral-bacterial synergism.

scholarly journals What will the next influenza season bring about: seasonal influenza or the new A(H1N1)v? An analysis of German influenza surveillance data

2009 ◽  
Vol 14 (32) ◽  
Author(s):  
H Uphoff ◽  
S Geis ◽  
A Grüber ◽  
A M Hauri
Keyword(s):  
Influenza A ◽  
Seasonal Influenza ◽  
Influenza Season ◽  
Influenza Viruses ◽  
Moderate Intensity ◽  
Influenza Surveillance ◽  
Influenza B ◽  
Low Intensity ◽  
Influenza A H1n1 ◽  
Using Data

For the next influenza season (winter 2009-10) the relative contributions to virus circulation and influenza-associated morbidity of the seasonal influenza viruses A(H3N2), A(H1N1) and B, and the new influenza A(H1N1)v are still unknown. We estimated the chances of seasonal influenza to circulate during the upcoming season using data of the German influenza sentinel scheme from 1992 to 2009. We calculated type and subtype-specific indices for past exposure and the corresponding morbidity indices for each season. For the upcoming season 2009-10 our model suggests that it is unlikely that influenza A(H3N2) will circulate with more than a low intensity, seasonal A(H1N1) with more than a low to moderate intensity, and influenza B with more than a low to median intensity. The probability of a competitive circulation of seasonal influenza A with the new A(H1N1)v is low, increasing the chance for the latter to dominate the next influenza season in Germany.

Population immunity for influenza in population of Sverdlovsk Region in epidemic season of 2018–2019

2020 ◽  
pp. 26-28
Author(s):  
I. A. Malchikov ◽  
A. V. Slobodenyuk ◽  
I. V. Vyalykh ◽  
A. Yu. Markaran ◽  
Yu. V. Grigorieva ◽  
...  
Keyword(s):  
Influenza A ◽  
Adult Population ◽  
Laboratory Data ◽  
Influenza Viruses ◽  
H3n2 Virus ◽  
Influenza B Virus ◽  
Influenza B ◽  
Epidemic Season ◽  
Influenza A H1n1 ◽  
Epidemic Period

Donor blood serum was tested to detect antibodies against circulating influenza viruses. The titer of specific antibodies was determined in the hemagglutination inhibition test (RTGA) against influenza viruses A/California/07/09(H1N1) pdm09, A/HongKong/4801/14(H3N2) and B/Brisben/46/15. In the pre-epidemic period 2018–2019, the immune layer of people with conditionally protective titers of antiviral antibodies was detected in terms of the lowest to A(H3N2) virus (50.0 %), the highest to influenza B (85.4 %). In the post-epidemic season of 2018–2019, the immune layer to influenza A(H1N1) pdm09 virus did not change significantly, which could indicate the preservation of the activity of this virus in the adult population; an increase in the immune layer of individuals with protective titers of antibodies to influenza A(H3N2) – 67.4 % and a decrease in influenza B virus – 49.2 %. A comparison of the results of laboratory data carried out in the pre- and post-epidemic seasons revealed significant differences in the number of people with average antibody titers against influenza A(H3N2) and B viruses (p < 0.05).

scholarly journals Report on influenza viruses received and tested by the Melbourne WHO Collaborating Centre for Reference and Research on Influenza in 2017

2019 ◽  
Vol 43 ◽  
Author(s):  
Merryn Roe ◽  
Matthew Kaye ◽  
Pina Iannello ◽  
Hilda Lau ◽  
Iwona Buettner ◽  
...  
Keyword(s):  
Influenza A ◽  
Seasonal Influenza ◽  
Vaccine Virus ◽  
Influenza Viruses ◽  
World Health ◽  
Influenza Surveillance ◽  
Influenza B ◽  
Neuraminidase Inhibitors ◽  
Response System ◽  
Surveillance And Response

As part of its role in the World Health Organization’s (WHO) Global Influenza Surveillance and Response System (GISRS), the WHO Collaborating Centre for Reference and Research on Influenza in Melbourne received a record total of 5866 human influenza positive samples during 2017. Viruses were analysed for their antigenic, genetic and antiviral susceptibility properties and were propagated in qualified cells and hens’ eggs for use as potential seasonal influenza vaccine virus candidates. In 2017, influenza A(H3) viruses predominated over influenza A(H1)pdm09 and B viruses, accounting for a total of 54% of all viruses analysed. The majority of A(H1)pdm09, A(H3) and influenza B viruses analysed at the Centre were found to be antigenically similar to the respective WHO recommended vaccine strains for the Southern Hemisphere in 2017. However, phylogenetic analysis indicated that the majority of circulating A(H3) viruses had undergone genetic drift relative to the WHO recommended vaccine strain for 2017. Of 3733 samples tested for susceptibility to the neuraminidase inhibitors oseltamivir and zanamivir, only two A(H1)pdm09 viruses and one A(H3) virus showed highly reduced inhibition by oseltamivir, while just one A(H1)pdm09 virus showed highly reduced inhibition by zanamivir.

scholarly journals Alternative Strategy for a Quadrivalent Live Attenuated Influenza Virus Vaccine

2018 ◽  
Vol 92 (21) ◽  
Author(s):  
Zhimin Wan ◽  
Stivalis Cardenas Garcia ◽  
Jing Liu ◽  
Jefferson Santos ◽  
Silvia Carnaccini ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Influenza A ◽  
Seasonal Influenza ◽  
Influenza Virus Vaccine ◽  
H1n1 Influenza ◽  
Influenza Viruses ◽  
Influenza B ◽  
Lethal Challenge ◽  
B Virus ◽  
Live Attenuated Influenza Virus

ABSTRACT Influenza virus infections continue to pose a major public health threat worldwide associated with seasonal epidemics and sporadic pandemics. Vaccination is considered the first line of defense against influenza. Live attenuated influenza virus vaccines (LAIVs) may provide superior responses compared to inactivated vaccines because the former can better elicit a combination of humoral and cellular responses by mimicking a natural infection. Unfortunately, during the 2013–2014, 2014–2015, and 2015–2016 seasons, concerns emerged about the effectiveness of the only LAIV approved in the United States that prevented the Advisory Committee on Immunization Practices (ACIP) from recommending its use. Such drawbacks open up the opportunity for alternative LAIV strategies that could overcome such concerns. Previously, we developed a combined strategy of temperature-sensitive mutations in the PB2 and PB1 segments and an epitope tag in the C terminus of PB1 that effectively attenuates influenza A viruses of avian and mammalian origin. More recently, we adopted a similar strategy for influenza B viruses. The resulting attenuated (att) influenza A and B viruses were safe, immunogenic, and protective against lethal influenza virus challenge in a variety of animal models. In this report, we provide evidence of the potential use of our att strategy in a quadrivalent LAIV (QIV) formulation carrying H3N2 and H1N1 influenza A virus subtype viruses and two antigenic lineages of influenza B viruses. In naive DBA/2J mice, two doses of the QIV elicited hemagglutination inhibition (HI) responses with HI titers of ≥40 and effectively protected against lethal challenge with prototypical pandemic H1N1 influenza A and influenza B virus strains. IMPORTANCE Seasonal influenza viruses infect 1 billion people worldwide and are associated with ∼500,000 deaths annually. In addition, the never-ending emergence of zoonotic influenza viruses associated with lethal human infections and of pandemic concern calls for the development of better vaccines and/or vaccination strategies against influenza virus. Regardless of the strategy, novel influenza virus vaccines must aim at providing protection against both seasonal influenza A and B viruses. In this study, we tested an alternative quadrivalent live attenuated influenza virus vaccine (QIV) formulation whose individual components have been previously shown to provide protection. We demonstrate in proof-of principle studies in mice that the QIV provides effective protection against lethal challenge with either influenza A or B virus.

scholarly journals Global dynamic spatiotemporal pattern of seasonal influenza since 2009 influenza pandemic

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Zhi-Wei Xu ◽  
Zhong-Jie Li ◽  
Wen-Biao Hu
Keyword(s):  
South Africa ◽  
Influenza A ◽  
Seasonal Influenza ◽  
Influenza Pandemic ◽  
Influenza Viruses ◽  
Sub Saharan Africa ◽  
Spatiotemporal Pattern ◽  
Influenza B ◽  
2009 Influenza Pandemic ◽  
Influenza Seasonality

Abstract Background Understanding the global spatiotemporal pattern of seasonal influenza is essential for influenza control and prevention. Available data on the updated global spatiotemporal pattern of seasonal influenza are scarce. This study aimed to assess the spatiotemporal pattern of seasonal influenza after the 2009 influenza pandemic. Methods Weekly influenza surveillance data in 86 countries from 2010 to 2017 were obtained from FluNet. First, the proportion of influenza A in total influenza viruses (PA) was calculated. Second, weekly numbers of influenza positive virus (A and B) were divided by the total number of samples processed to get weekly positive rates of influenza A (RWA) and influenza B (RWB). Third, the average positive rates of influenza A (RA) and influenza B (RB) for each country were calculated by averaging RWA, and RWB of 52 weeks. A Kruskal-Wallis test was conducted to examine if the year-to-year change in PA in all countries were significant, and a universal kriging method with linear semivariogram model was used to extrapolate RA and RB in all countries. Results PA ranged from 0.43 in Zambia to 0.98 in Belarus, and PA in countries with higher income was greater than those countries with lower income. The spatial patterns of high RB were the highest in sub-Saharan Africa, Asia-Pacific region and South America. RWA peaked in early weeks in temperate countries, and the peak of RWB occurred a bit later. There were some temperate countries with non-distinct influenza seasonality (e.g., Mauritius and Maldives) and some tropical/subtropical countries with distinct influenza seasonality (e.g., Chile and South Africa). Conclusions Influenza seasonality is not predictable in some temperate countries, and it is distinct in Chile, Argentina and South Africa, implying that the optimal timing for influenza vaccination needs to be chosen with caution in these unpredictable countries.

scholarly journals Circulating influenza viruses and the effectiveness of seasonal influenza vaccine in Romania, season 2012-2013 / Virusurile gripale circulante și eficacitatea vaccinului gripal sezonier în România, în sezonul 2012-2013

2015 ◽  
Vol 23 (1) ◽  
Author(s):  
Daniela Pitigoi ◽  
George Necula ◽  
Viorel Alexandrescu ◽  
Maria Elena Mihai ◽  
Carmen Maria Cherciu ◽  
...  
Keyword(s):  
Influenza Vaccine ◽  
Vaccine Strain ◽  
Influenza A ◽  
Seasonal Influenza ◽  
Influenza Viruses ◽  
Nucleotide Sequencing ◽  
Influenza B ◽  
Seasonal Influenza Vaccine ◽  
Negative Case ◽  
Influenza A H1n1

AbstractBackgound. Using influenza epidemiological and virological surveillance data, we aimed at investigating the profile of influenza viruses circulating in Romania during the season 2012-2013 and estimating the effectiveness (VE) of the seasonal vaccine. Methods. We tested all specimens collected from patients with influenza like illness (ILI) in the national surveillance system between week 40/2012 to week 20/2013. Influenza A/B positive specimens identified by molecular detection (RT-PCR) were further characterized. We used hemagglutination inhibition assay for antigenic characterization and chemiluminiscence assay for the antiviral susceptibility testing. Subsequently we conducted nucleotide sequencing of hemagglutinin and neuraminidase genes and phylogenetic tree analyses. We estimated influenza VE using the test negative case-control study design, as 1-odds ratio of vaccination among ILI cases positive for influenza and ILI negative controls. Results and Discussions. We tested 1087 specimens, and 537 cases were positive (56.2% influenza B, 40.6% A(H1N1)pdm09, 3.2% A(H3N2). Sixty-four influenza viruses were antigenically and/or genetically characterized. A(H1N1)pdm09 viruses were related to the vaccine strain A/ California/07/2009 and clustered with genetic group 6 similar to A/St. Petersburg/27/2011. Influenza B viruses belonged to clade 2 of type B/Yamagata lineage, related to B/Estonia/55669/2011 except one, B/Victoria lineage, representative strain B/Brisbane/60/2008. A(H3) viruses clustered with group 3C of the A/Victoria/208/2009 clade, similar to the vaccine strain A/Victoria/361/2011. All tested strains (57) demonstrated susceptibility to oseltamivir and zanamivir. The adjusted seasonal influenza vaccine effectiveness against influenza A(H1N1)pdm09 (N=119) was 76.9% (95% CI: -113.4, 98.5), suggesting a good protection, consistent with the good match between the vaccine and circulating strains.

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