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  1. Fulltext Detection of reassortant influenza B strains from 2004 to 2015 seasons in Barcelona (Catalonia, Spain) by whole genome sequencing
    Andrés C, Del Cuerpo M, Rabella N, Piñana M, Iglesias-Cabezas MJ, González-Sánchez A, et al.
    Virus Res, 2023 Jun;330:199089.
    PMID: 37011863 DOI: 10.1016/j.virusres.2023.199089
    BACKGROUND: Influenza B viruses (FLUBV) have segmented genomes which enables the virus to evolve by segment reassortment. Since the divergence of both FLUBV lineages, B/Victoria/2/87 (FLUBV/VIC) and B/Yamagata/16/88 (FLUBV/YAM), PB2, PB1 and HA have kept the same ancestor, while some reassortment events in the other segments have been reported worldwide. The aim of the present study was to find out reassortment episodes in FLUBV strains detected in cases attended at Hospital Universitari Vall d'Hebron and Hospital de la Santa Creu i Sant Pau (Barcelona, Spain) from 2004 to 2015 seasons.

    METHODS: From October 2004 to May 2015, respiratory specimens were received from patients with respiratory tract infection suspicion. Influenza detection was carried out by either cell culture isolation, immunofluorescence or PCR-based assays. A RT-PCR was performed to distinguish both lineages by agarose gel electrophoresis. Whole genome amplification was performed using the universal primer set by Zhou et al. in 2012, and subsequently sequenced using Roche 454 GS Junior platform. Bioinformatic analysis was performed to characterise the sequences with B/Malaysia/2506/2007 and B/Florida/4/2006 corresponding sequences as reference of (B/VIC) and (B/YAM), respectively.

    RESULTS: A total of 118 FLUBV (75 FLUBV/VIC and 43 FLUBV/YAM), from 2004 to 2006, 2008-2011 and 2012-2015 seasons, were studied. The whole genome of 58 FLUBV/VIC and 42 FLUBV/YAM viruses was successfully amplified. Based on HA sequences, most FLUBV/VIC viruses (37; 64%) belonged to clade 1A (B/Brisbane/60/2008) except to 11 (19%), which fell within clade 1B (B/HongKong/514/2009) and 10 (17%) to B/Malaysia/2506/2004. Nine (20%) FLUBV/YAM viruses belonged to clade 2 (B/Massachusetts/02/2012), 18 (42%) to clade 3 (B/Phuket/3073/2013) and 15 (38%) fell within Florida/4/2006. Numerous intra-lineage reassortments in PB2, PB1, NA and NS were found in 2 2010-2011 viruses. An important inter-lineage reassortment event from 2008 to 2009 (11), 2010-2011 (26) and 2012-2013 (3) FLUBV/VIC (clade 1) strains to FLUBV/YAM (clade 3) was found, in addition to 1 reassortant NS in 2010-2011 B/VIC virus.

    CONCLUSIONS: Intra- and inter-lineage reassortment episodes were revealed by WGS. While PB2-PB1-HA remained in complex, NP and NS reassortant viruses were found in both lineages. Despite reassorment events are not often, the characterisation only by HA and NA sequences might be underestimating their detection.

    Matched MeSH terms: Influenza B virus/genetics
  2. [Genetic variation of the hemagglutinin and neuraminidase of influenza B viruses isolated in Ningbo during 2010-2012]
    Hu FJ, Li YD, Jiao SL, Zhang S
    Zhonghua Yu Fang Yi Xue Za Zhi, 2013 Dec;47(12):1100-4.
    PMID: 24529267
    To investigate the epidemiological characteristics of influenza B viruses and explore the genetic evolution characteristics of the hemagglutinin(HA) and neuraminidase(NA) genes of local isolated strains in Ningbo, Southeast China, during 2010 to 2012.
    Matched MeSH terms: Influenza B virus/classification; Influenza B virus/genetics*; Influenza B virus/isolation & purification
  3. Fulltext Whole-Genome Phylogenetic Analysis of Influenza B/Phuket/3073/2013-Like Viruses and Unique Reassortants Detected in Malaysia between 2012 and 2014
    Oong XY, Ng KT, Tan JL, Chan KG, Kamarulzaman A, Chan YF, et al.
    PLoS One, 2017;12(1):e0170610.
    PMID: 28129386 DOI: 10.1371/journal.pone.0170610
    Reassortment of genetic segments between and within influenza B lineages (Victoria and Yamagata) has been shown to generate novel reassortants with unique genetic characteristics. Based on hemagglutinin (HA) and neuraminidase (NA) genes, recent surveillance study has identified reassortment properties in B/Phuket/3073/2013-like virus, which is currently used in the WHO-recommended influenza vaccine. To understand the potential reassortment patterns for all gene segments, four B/Phuket/3073/2013-like viruses and two unique reassortants (one each from Yamagata and Victoria) detected in Malaysia from 2012-2014 were subjected to whole-genome sequencing. Each gene was phylogenetically classified into lineages, clades and sub-clades. Three B/Phuket/3073/2013-like viruses from Yamagata lineage were found to be intra-clade reassortants, possessing PA and NA genes derived from Stockholm/12-like sub-clade, while the remaining genes from Wisconsin/01-like sub-clade (both sub-clades were within Yamagata Clade 3/Yam-3). However, the other B/Phuket/3073/2013-like virus had NS gene that derived from Stockholm/12-like sub-clade instead of Wisconsin/01-like sub-clade. One inter-clade reassortant had Yamagata Clade 2/Yam-2-derived HA and NP, and its remaining genes were Yam-3-derived. Within Victoria Clade 1/Vic-1 in Victoria lineage, one virus had intra-clade reassortment properties: HA and PB2 from Vic-1B sub-clade, MP and NS from a unique sub-clade "Vic-1C", and the remaining genes from Vic-1A sub-clade. Although random reassortment event may generate unique reassortants, detailed phylogenetic classification of gene segments showed possible genetic linkage between PA and NA genes in B/Phuket/3073/2013-like viruses, which requires further investigation. Understanding on reassortment patterns in influenza B evolution may contribute to future vaccine design.
    Matched MeSH terms: Influenza B virus/classification; Influenza B virus/genetics*; Influenza B virus/pathogenicity
  4. [Analysis of genetic features of influenza B virus in Hunan province from 2007 to 2010]
    Liu YZ, Zhao X, Huang YW, Chen Z, Li FC, Gao LD, et al.
    Zhonghua Yu Fang Yi Xue Za Zhi, 2012 Mar;46(3):258-63.
    PMID: 22800599
    To investigate the gene variations of influenza B virus isolated in Hunan province from 2007 to 2010.
    Matched MeSH terms: Influenza B virus/genetics*; Influenza B virus/isolation & purification
  5. Antiviral activity of Embelia ribes Burm. f. against influenza virus in vitro
    Hossan MS, Fatima A, Rahmatullah M, Khoo TJ, Nissapatorn V, Galochkina AV, et al.
    Arch Virol, 2018 Aug;163(8):2121-2131.
    PMID: 29633078 DOI: 10.1007/s00705-018-3842-6
    Viral respiratory infections are raising serious concern globally. Asian medicinal plants could be useful in improving the current treatment strategies for influenza. The present study examines the activity of five plants from Bangladesh against influenza virus. MDCK cells infected with influenza virus A/Puerto Rico/8/34 (H1N1) were treated with increasing concentrations of ethyl acetate extracts, and their cytotoxicity (CC50), virus-inhibiting activity (IC50), and selectivity index (SI) were calculated. The ethyl acetate extract of fruits of Embelia ribes Burm. f. (Myrsinaceae) had the highest antiviral activity, with an IC50 of 0.2 µg/mL and a SI of 32. Its major constituent, embelin, was further isolated and tested against the same virus. Embelin demonstrated antiviral activity, with an IC50 of 0.3 µM and an SI of 10. Time-of-addition experiments revealed that embelin was most effective when added at early stages of the viral life cycle (0-1 h postinfection). Embelin was further evaluated against a panel of influenza viruses including influenza A and B viruses that were susceptible or resistant to rimantadine and oseltamivir. Among the viruses tested, avian influenza virus A/mallard/Pennsylvania/10218/84 (H5N2) was the most susceptible to embelin (SI = 31), while A/Aichi/2/68 (H3N2) virus was the most resistant (SI = 5). In silico molecular docking showed that the binding site for embelin is located in the receptor-binding domain of the viral hemagglutinin. The results of this study provide evidence that E. ribes can be used for development of a novel alternative anti-influenza plant-based agent.
    Matched MeSH terms: Influenza B virus/drug effects*; Influenza B virus/physiology
  6. Capture of cell culture-derived influenza virus by lectins: strain independent, but host cell dependent
    Opitz L, Zimmermann A, Lehmann S, Genzel Y, Lübben H, Reichl U, et al.
    J Virol Methods, 2008 Dec;154(1-2):61-8.
    PMID: 18840469 DOI: 10.1016/j.jviromet.2008.09.004
    Strategies to control influenza outbreaks are focused mainly on prophylactic vaccination. Human influenza vaccines are trivalent blends of different virus subtypes. Therefore and due to frequent antigenic drifts, strain independent manufacturing processes are required for vaccine production. This study verifies the strain independency of a capture method based on Euonymus europaeus lectin-affinity chromatography (EEL-AC) for downstream processing of influenza viruses under various culture conditions propagated in MDCK cells. A comprehensive lectin binding screening was conducted for two influenza virus types from the season 2007/2008 (A/Wisconsin/67/2005, B/Malaysia/2506/2004) including a comparison of virus-lectin interaction by surface plasmon resonance technology. EEL-AC resulted in a reproducible high product recovery rate and a high degree of contaminant removal in the case of both MDCK cell-derived influenza virus types demonstrating clearly the general applicability of EEL-AC. In addition, host cell dependency of EEL-AC was studied with two industrial relevant cell lines: Vero and MDCK cells. However, the choice of the host cell lines is known to lead to different product glycosylation profiles. Hence, altered lectin specificities have been observed between the two cell lines, requiring process adaptations between different influenza vaccine production systems.
    Matched MeSH terms: Influenza B virus/growth & development*; Influenza B virus/isolation & purification*
  7. Molecular analysis of isolates from influenza B outbreaks in the U.S. and Nepal, 2005
    Daum LT, Canas LC, Klimov AI, Shaw MW, Gibbons RV, Shrestha SK, et al.
    Arch Virol, 2006 Sep;151(9):1863-74.
    PMID: 16736092
    Currently circulating influenza B viruses can be divided into two antigenically and genetically distinct lineages referred to by their respective prototype strains, B/Yamagata/16/88 and B/Victoria/2/87, based on amino acid differences in the hemagglutinin surface glycoprotein. During May and July 2005, clinical specimens from two early season influenza B outbreaks in Arizona and southeastern Nepal were subjected to antigenic (hemagglutinin inhibition) and nucleotide sequence analysis of hemagglutinin (HA1), neuraminidase (NA), and NB genes. All isolates exhibited little reactivity with the B/Shanghai/361/2002 (B/Yamagata-like) vaccine strain and significantly reduced reactivity with the previous 2003/04 B/Hong Kong/330/2001 (B/Victoria-like) vaccine strain. The majority of isolates were antigenically similar to B/Hawaii/33/2004, a B/Victoria-like reference strain. Sequence analysis indicated that 33 of 34 isolates contained B/Victoria-like HA and B/Yamagata-like NA and NB proteins. Thus, these outbreak isolates are both antigenically and genetically distinct from the current Northern Hemisphere vaccine virus strain as well as the previous 2003-04 B/Hong Kong/330/2001 (B/Victoria lineage) vaccine virus strain but are genetically similar to B/Malaysia/2506/2004, the vaccine strain proposed for the coming seasons in the Northern and Southern Hemispheres. Since these influenza B outbreaks occurred in two very distant geographical locations, these viruses may continue to circulate during the 2006 season, underscoring the importance of rapid molecular monitoring of HA, NA and NB for drift and reassortment.
    Matched MeSH terms: Influenza B virus/genetics*; Influenza B virus/immunology; Influenza B virus/isolation & purification*
  8. [The 2006/'07 influenza season in the Netherlands and the vaccine composition for the 2007/'08 season]
    de Jong JC, Rimmelzwaan GF, Donker GA, Meijer A, Fouchier RA, Osterhaus AD
    Ned Tijdschr Geneeskd, 2007 Sep 29;151(39):2158-65.
    PMID: 17957994
    The influenza epidemic of 2006/'07 began late in the season, like the two previous influenza epidemics. In week 8 a peak of modest height was reached. As usual, the causal strains were mainly A/H3N2 viruses and to a lesser extent A/H1N1 and B viruses. A new A/H1N1 virus variant has emerged, an event that on average takes place only every 10 years. However, almost all A/H1N1 virus isolates belonged to the old variant and were similar to the vaccine virus. The A/H3N2 virus isolates appeared to deviate from the vaccine strain, but after antigenic cartographic analysis and correction for low avidity they proved also closely related to the vaccine strain. The few type B virus isolates belonged to the B/Yamagata/16/88 lineage, whereas the used B vaccine virus had been chosen from the B/Victoria/2/87 lineage. The vaccine therefore will have provided almost optimal protection against the circulating influenza A/H1N1 and A/H3N2 viruses but not against the influenza B viruses. For the 2007/'08 influenza season the World Health Organization has recommended the following vaccine composition: A/Solomon Islands/3/06 (H1N1) (new), A/Wisconsin/67/05 (H3N2), and B/Malaysia/2506/04.
    Matched MeSH terms: Influenza B virus/immunology
  9. Fulltext Evolution of Influenza B Virus in Kuala Lumpur, Malaysia, between 1995 and 2008
    Sam IC, Su YC, Chan YF, Nor'E SS, Hassan A, Jafar FL, et al.
    J Virol, 2015 Sep;89(18):9689-92.
    PMID: 26136576 DOI: 10.1128/JVI.00708-15
    Influenza B virus causes significant disease but remains understudied in tropical regions. We sequenced 72 influenza B viruses collected in Kuala Lumpur, Malaysia, from 1995 to 2008. The predominant circulating lineage (Victoria or Yamagata) changed every 1 to 3 years, and these shifts were associated with increased incidence of influenza B. We also found poor lineage matches with recommended influenza virus vaccine strains. While most influenza B virus lineages in Malaysia were short-lived, one circulated for 3 to 4 years.
    Matched MeSH terms: Influenza B virus/genetics*
  10. Influenza B outbreak in female psychiatric ward of Hospital Kuala Lumpur, Malaysia
    Mohamad Isa MF, Tan JM, Abdul Aziz MF, Leong CL
    Med J Malaysia, 2018 12;73(6):405-406.
    PMID: 30647214
    Influenza outbreaks in tropical countries are rarely reported. This article reports four cases of influenza within a psychiatric ward of a tertiary hospital in Malaysia. These were patients with severe mental illness who were involuntarily admitted and did not show the classical triad of influenza-like-illness (ILI) at the beginning. However, severe respiratory complications developed requiring intubation. Referral and cooperation with the infectious disease team was initiated to help manage the outbreak while continuing psychiatric treatment. Incidences of influenza among hospitalised psychiatric patients should be treated seriously with immediate multidisciplinary approach to prevent severe unwanted complications.
    Matched MeSH terms: Influenza B virus*
  11. Seasonal influenza virus strains circulating in Malaysia from 2005 to 2009
    Saat Z, Abdul Rashid TR, Yusof MA, Kassim FM, Thayan R, Kuen LS, et al.
    Southeast Asian J Trop Med Public Health, 2010 Nov;41(6):1368-73.
    PMID: 21329312
    From 2005 to 2009, the Institute for Medical Research (IMR), Kuala Lumpur received a total of 7,117 respiratory specimens from patients with influenza-like illness (ILI) for influenza screening. Seasonal influenza virus was isolated from 17.3% of patients with ILI in 2005, 31.6% in 2006, 12.8% in 2007, 10.2% in 2008 and 13.5% in 2009. There were one or more influenza A and B virus strains circulating in Malaysia throughout the year, with distinctly a peak in May to August. The predominant circulating strains of seasonal influenza A were A/California/7/2004-like (H3N2) in 2005, A/New Caledonia/20/99-like (H1N1) in 2006, A/ Brisbane/10/2007-like (H3N2) in 2007 and 2008, and A/Perth/16/2009-like (H3N2) virus in 2009. The predominant circulating strains of influenza B were B/Hong Kong/330/2001-like in 2005, B/Malaysia/2506/2004-like in 2006, B/Florida/4/2006-like in 2007 and 2008, and B/Brisbane/60/2008-like in 2009.
    Matched MeSH terms: Influenza B virus/isolation & purification*
  12. Cold adaptation improves the growth of seasonal influenza B vaccine viruses
    Kim H, Schoofs P, Anderson DA, Tannock GA, Rockman SP
    Vaccine, 2014 May 1;32(21):2474-9.
    PMID: 24631096 DOI: 10.1016/j.vaccine.2014.02.079
    Gene reassortment has proved useful in improving yields of influenza A antigens of egg-based inactivated vaccines, but similar approaches have been difficult with influenza B antigens. Current regulations for influenza vaccine seed viruses limit the number of egg passages and as a result resultant yields from influenza B vaccine seed viruses are frequently inconsistent. Therefore, reliable approaches to enhance yields of influenza B vaccine seed viruses are required for efficient vaccine manufacture. In the present study three stable cold-adapted (ca) mutants, caF, caM and caB derived from seasonal epidemic strains, B/Florida/4/2006, B/Malaysia/2506/2004 and B/Brisbane/60/2008 were prepared, which produced high hemagglutinin antigen yields and also increased viral yields of reassortants possessing the desired 6:2 gene constellation. The results demonstrate that consistent improvements in yields of influenza B viruses can be obtained by cold adaptation following extended passage. Taken together, the three ca viruses were shown to have potential as donor viruses for the preparation of high-yielding influenza B vaccine viruses by reassortment.
    Matched MeSH terms: Influenza B virus/genetics; Influenza B virus/growth & development*
  13. [The 2005-2006 influenza season in the Netherlands and the vaccine composition for the 2006-2007 season]
    Rimmelzwaan GF, de Jong JC, Donker GA, Meijer A, Fouchier RA, Osterhaus AD
    Ned Tijdschr Geneeskd, 2006 Oct 7;150(40):2209-14.
    PMID: 17061434
    The first sign of influenza activity in the Netherlands during the 2005-2006 influenza season was the isolation of influenza viruses in the last week of 2005. From Week 1 of 2006 onwards, an increase in clinical influenza activity was also observed that did not return to baseline levels until Week 15. Two waves of influenza activity were observed with peak incidences of 13.8 and 9.8 influenza-like illnesses per 10,000 inhabitants on Weeks 7 and 12, respectively. The first wave of influenza was caused primarily by influenza B viruses, whereas the second wave was caused predominantly by influenza A/H3N2 viruses. The influenza B viruses appeared to belong to two different phylogenetic lineages and were antigenically distinguishable from the vaccine strain. The isolated influenza A/H3N2 viruses were closely related to the vaccine strain for this subtype and only minor antigenic differences with the vaccine strain were observed for a limited number of isolates. Only a small number of influenza A/H1N1 viruses were isolated, which all closely resembled the H1N1 vaccine strain. For the 2006-2007 influenza season, the World Health Organization has recommended the following vaccine composition: A/Wisconsin/67/05 (H3N2), A/New Caledonia/20/99 (H1N1) and B/Malaysia/2506/05.
    Matched MeSH terms: Influenza B virus/immunology*; Influenza B virus/isolation & purification
  14. Molecular characterization of influenza viruses circulating in Northern Italy during two seasons (2005/2006 and 2006/2007) of low influenza activity
    Pariani E, Amendola A, Zappa A, Bianchi S, Colzani D, Anselmi G, et al.
    J Med Virol, 2008 Nov;80(11):1984-91.
    PMID: 18814246 DOI: 10.1002/jmv.21323
    The influenza activity and circulation of influenza viruses in Lombardy (the most populous Italian region) were observed during two consecutive seasons (2005/2006 and 2006/2007) characterized by low influenza activity by the Italian Influenza Surveillance Network. The molecular characteristics of circulating viruses were analyzed to evaluate the introduction of new variants and emergence of vaccine-escape viruses. In both seasons, the epidemic in Lombardy was sustained almost exclusively by influenza A viruses, accounting for 80.5% and 93.6% of total detections, respectively, and the co-circulation of A/H3 viruses belonging to distinct phylogenetic groups was observed. The A/H1N1 viruses isolated during the 2005/2006 season were closely related to A/New Caledonia/20/99, while the hemagglutinin (HA) sequences of the A/H1N1 viruses from the 2006/2007 season exhibited a greater diversity. These viruses were A/Solomon Islands/3/2006-like and showed several variants. All B isolates were similar to B/Malaysia/2506/2004 belonging to the B/Victoria/2/87-lineage. Influenza B virus was the dominant virus in Europe in the 2005/2006 season and accounted for the 20% of total detections in Lombardy. Overall, the viruses studied presented heterogeneity in their HA sequences suggesting the circulation of a miscellaneous set of variants during the two seasons notwithstanding the medium-low activity of influenza. The importance of virological surveillance of influenza viruses is recognized widely and the molecular characterization of the viruses, especially in vaccinated subjects, is of particular importance to evaluate the introduction and circulation of new variants.
    Matched MeSH terms: Influenza B virus/classification*; Influenza B virus/isolation & purification*
  15. Seasonal influenza activity based on laboratory surveillance in Malaysia, 2011-2016
    Sam IC, Noraini W, Sandhu SS, Norizah I, Selvanesan S, Thayan R, et al.
    J Med Virol, 2019 03;91(3):498-502.
    PMID: 30199092 DOI: 10.1002/jmv.25313
    Influenza seasonality in equatorial countries is little understood. Seasonal and alert influenza thresholds were determined for Malaysia, using laboratory-based data obtained from the Malaysia Influenza Surveillance System and a major teaching hospital, from 2011 to 2016. Influenza was present year-round, with no clear annual seasons. Variable periods of higher transmission occurred inconsistently, in November to December, January to March, July to September, or a combination of these. These coincide with seasons in the nearby southeast Asian countries or winter seasons of the northern and southern hemispheres. Changes in the predominant circulating influenza type were only sometimes associated with increased transmission. The data can provide public health interventions such as vaccines.
    Matched MeSH terms: Influenza B virus
  16. Fulltext Immunogenicity and safety of quadrivalent versus trivalent inactivated influenza vaccine: a randomized, controlled trial in adults
    Beran J, Peeters M, Dewé W, Raupachová J, Hobzová L, Devaster JM
    BMC Infect Dis, 2013;13:224.
    PMID: 23688546 DOI: 10.1186/1471-2334-13-224
    Two phylogenetic lineages of influenza B virus coexist and circulate in the human population (B/Yamagata and B/Victoria) but only one B-strain is included in each seasonal vaccine. Mismatch regularly occurs between the recommended and circulating B-strain. Inclusion of both lineages in vaccines may offer better protection against influenza.
    Matched MeSH terms: Influenza B virus/immunology
  17. A case-control study of influenza vaccine effectiveness among Malaysian pilgrims attending the Haj in Saudi Arabia
    Mustafa AN, Gessner BD, Ismail R, Yusoff AF, Abdullah N, Ishak I, et al.
    Int J Infect Dis, 2003 Sep;7(3):210-4.
    PMID: 14563225
    To determine influenza vaccine effectiveness against clinically defined influenza-like illness among Malaysian pilgrims attending the Haj in Saudi Arabia.
    Matched MeSH terms: Influenza B virus/immunology
  18. Production of cell culture (MDCK) derived live attenuated influenza vaccine (LAIV) in a fully disposable platform process
    George M, Farooq M, Dang T, Cortes B, Liu J, Maranga L
    Biotechnol Bioeng, 2010 Aug 15;106(6):906-17.
    PMID: 20589670 DOI: 10.1002/bit.22753
    The majority of influenza vaccines are manufactured using embryonated hens' eggs. The potential occurrence of a pandemic outbreak of avian influenza might reduce or even eliminate the supply of eggs, leaving the human population at risk. Also, the egg-based production technology is intrinsically cumbersome and not easily scalable to provide a rapid worldwide supply of vaccine. In this communication, the production of a cell culture (Madin-Darby canine kidney (MDCK)) derived live attenuated influenza vaccine (LAIV) in a fully disposable platform process using a novel Single Use Bioreactor (SUB) is presented. The cell culture and virus infection was maintained in a disposable stirred tank reactor with PID control of pH, DO, agitation, and temperature, similar to traditional glass or stainless steel bioreactors. The application of this technology was tested using MDCK cells grown on microcarriers in proprietary serum free medium and infection with 2006/2007 seasonal LAIV strains at 25-30 L scale. The MDCK cell growth was optimal at the agitation rate of 100 rpm. Optimization of this parameter allowed the cells to grow at a rate similar to that achieved in the conventional 3 L glass stirred tank bioreactors. Influenza vaccine virus strains, A/New Caledonia/20/99 (H1N1 strain), A/Wisconsin/67/05 (H3N2 strain), and B/Malaysia/2506/04 (B strain) were all successfully produced in SUB with peak virus titers > or =8.6 log(10) FFU/mL. This result demonstrated that more than 1 million doses of vaccine can be produced through one single run of a small bioreactor at the scale of 30 L and thus provided an alternative to the current vaccine production platform with fast turn-around and low upfront facility investment, features that are particularly useful for emerging and developing countries and clinical trial material production.
    Matched MeSH terms: Influenza B virus/growth & development*
  19. Fulltext Epidemiological and Evolutionary Dynamics of Influenza B Viruses in Malaysia, 2012-2014
    Oong XY, Ng KT, Lam TT, Pang YK, Chan KG, Hanafi NS, et al.
    PLoS One, 2015;10(8):e0136254.
    PMID: 26313754 DOI: 10.1371/journal.pone.0136254
    Epidemiological and evolutionary dynamics of influenza B Victoria and Yamagata lineages remained poorly understood in the tropical Southeast Asia region, despite causing seasonal outbreaks worldwide. From 2012-2014, nasopharyngeal swab samples collected from outpatients experiencing acute upper respiratory tract infection symptoms in Kuala Lumpur, Malaysia, were screened for influenza viruses using a multiplex RT-PCR assay. Among 2,010/3,935 (51.1%) patients infected with at least one respiratory virus, 287 (14.3%) and 183 (9.1%) samples were tested positive for influenza A and B viruses, respectively. Influenza-positive cases correlate significantly with meteorological factors-total amount of rainfall, relative humidity, number of rain days, ground temperature and particulate matter (PM10). Phylogenetic reconstruction of haemagglutinin (HA) gene from 168 influenza B viruses grouped them into Yamagata Clade 3 (65, 38.7%), Yamagata Clade 2 (48, 28.6%) and Victoria Clade 1 (55, 32.7%). With neuraminidase (NA) phylogeny, 30 intra-clade (29 within Yamagata Clade 3, 1 within Victoria Clade 1) and 1 inter-clade (Yamagata Clade 2-HA/Yamagata Clade 3-NA) reassortants were identified. Study of virus temporal dynamics revealed a lineage shift from Victoria to Yamagata (2012-2013), and a clade shift from Yamagata Clade 2 to Clade 3 (2013-2014). Yamagata Clade 3 predominating in 2014 consisted of intra-clade reassortants that were closely related to a recent WHO vaccine candidate strain (B/Phuket/3073/2013), with the reassortment event occurred approximately 2 years ago based on Bayesian molecular clock estimation. Malaysian Victoria Clade 1 viruses carried H274Y substitution in the active site of neuraminidase, which confers resistance to oseltamivir. Statistical analyses on clinical and demographic data showed Yamagata-infected patients were older and more likely to experience headache while Victoria-infected patients were more likely to experience nasal congestion and sore throat. This study describes the evolution of influenza B viruses in Malaysia and highlights the importance of continuous surveillance for better vaccination policy in this region.
    Matched MeSH terms: Influenza B virus/genetics*
  20. Influenza B outbreak among influenza-vaccinated welfare home residents in Singapore
    Win MK, Chow A, Chen M, Lau YF, Ooi EE, Leo YS
    Ann Acad Med Singap, 2010 Jun;39(6):448-52.
    PMID: 20625620
    INTRODUCTION: Outbreaks of acute respiratory illness occur commonly in long-term care facilities (LTCF), due to the close proximity of residents. Most influenza outbreak reports have been from temperate countries. This study reports an outbreak of influenza B among a highly immunised resident population in a welfare home in tropical Singapore, and discusses vaccine efficacy and the role of acute respiratory illness surveillance for outbreak prevention and control.

    MATERIALS AND METHODS: During the period from 16 to 21 March 2007, outbreak investigations and active case finding were carried out among residents and nursing staff at the welfare home. Interviews and medical notes review were conducted to obtain epidemiological and clinical data. Hospitalised patients were tested for respiratory pathogens. Further genetic studies were also carried out on positive respiratory samples.

    RESULTS: The overall clinical attack rate was 9.4% (17/180) in residents and 6.7% (2/30) in staff. All infected residents and staff had received influenza immunisation. Fifteen residents were hospitalised, with 2 developing severe complications. Genetic sequencing revealed that the outbreak strain had an 8.2% amino acid difference from B/Malaysia/2506/2004, the 2006 southern hemisphere influenza vaccine strain, which the residents and staff had earlier received.

    CONCLUSIONS: A mismatch between the vaccine and circulating influenza virus strains can result in an outbreak in a highly immunised LTCF resident population. Active surveillance for acute respiratory illness in LTCFs could be implemented for rapid detection of antigenic drift. Enhanced infection control and other preventive measures can then be deployed in a timely manner to mitigate the effect of any outbreaks.

    Matched MeSH terms: Influenza B virus/immunology*
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