scholarly journals Genetic and Antigenic Characterization of an Influenza A(H3N2) Outbreak in Cambodia and the Greater Mekong Subregion during the COVID-19 Pandemic, 2020

2021 ◽  
Author(s):  
Jurre Y. Siegers ◽  
Vijaykrishna Dhanasekaran ◽  
Ruopeng Xie ◽  
Yi-Mo Deng ◽  
Sarika Patel ◽  
...  
Keyword(s):  
Influenza Vaccine ◽  
Northern Hemisphere ◽  
Influenza A ◽  
Respiratory Diseases ◽  
Vaccine Virus ◽  
Control Measures ◽  
Influenza Surveillance ◽  
Multiple Virus ◽  
Influenza Activity ◽  
Greater Mekong Subregion

Introduction of non-pharmaceutical interventions to control COVID-19 in early 2020 coincided with a global decrease in active influenza circulation. However, between July and November 2020, an influenza A(H3N2) epidemic occurred in Cambodia and in other neighboring countries in the Greater Mekong Subregion in Southeast Asia. We characterized the genetic and antigenic evolution of A(H3N2) in Cambodia and found that the 2020 epidemic comprised genetically and antigenically similar viruses of Clade3C2a1b/131K/94N, but they were distinct from the WHO recommended influenza A(H3N2) vaccine virus components for 2020-2021 Northern Hemisphere season. Phylogenetic analysis revealed multiple virus migration events between Cambodia and bordering countries, with Laos PDR and Vietnam also reporting similar A(H3N2) epidemics immediately following the Cambodia outbreak: however, there was limited circulation of these viruses elsewhere globally. In February 2021, a virus from the Cambodian outbreak was recommended by WHO as the prototype virus for inclusion in the 2021-2022 Northern Hemisphere influenza vaccine. Importance The 2019 coronavirus disease (COVID-19) pandemic has significantly altered the circulation patterns of respiratory diseases worldwide and disrupted continued surveillance in many countries. Introduction of control measures in early 2020 against Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) infection has resulted in a remarkable reduction in the circulation of many respiratory diseases. Influenza activity has remained at historically low levels globally since March 2020, even when increased influenza testing was performed in some countries. Maintenance of the influenza surveillance system in Cambodia in 2020 allowed for the detection and response to an influenza A(H3N2) outbreak in late 2020, resulting in the inclusion of this virus in the 2021-2022 Northern Hemisphere influenza vaccine.

scholarly journals Epidemiological and virological assessment of influenza activity in Europe, during the 2006-2007 winter

2008 ◽  
Vol 13 (34) ◽  
Author(s):  
J MS Arkema ◽  
A Meijer ◽  
T J Meerhoff ◽  
J Van Der Velden ◽  
W J Paget ◽  
...  
Keyword(s):  
Influenza A ◽  
New Caledonia ◽  
Respiratory Infections ◽  
Vaccine Virus ◽  
Influenza Surveillance ◽  
Clinical Activity ◽  
Influenza B ◽  
Influenza Like Illness ◽  
Influenza Activity ◽  
Virus Strains

Influenza surveillance in Europe is based on influenza surveillance networks that cooperate and share information through the European Influenza Surveillance Scheme (EISS). EISS collected clinical and virological data on influenza in 33 countries during the 2006-2007 winter. Influenza activity started around 1 January and first occurred in Greece, Scotland and Spain. It then moved gradually across Europe from south to north and lasted until the end of March. In 29 out of 33 countries, the consultation rates for influenza-like-illness or acute respiratory infections in the winter of 2006-2007 were similar or somewhat higher than in the 2005-2006 winter. The highest consultation rates for influenza-like-illness were generally observed among children aged 0-4 years and 5-14 years. The predominant virus strain was influenza A (97% of total detections) of the H3 subtype (93% of H-subtyped A viruses; 7% were A(H1)). The influenza A(H3) and A(H1) viruses were similar to the vaccine reference strains for the 2006-2007 season, A/Wisconsin/67/2005 (H3N2) and A/New Caledonia/20/99 (H1N1) respectively. The majority of the influenza B viruses were similar to the reference strain B/Malaysia/2506/2004, included in the 2006-2007 vaccine. In conclusion, the 2006-2007 influenza season in Europe was characterised by moderate clinical activity, a south to north spread pattern across Europe, and a dominance of influenza A(H3). Overall there was a good match between the vaccine virus strains and the reported virus strains.

scholarly journals Start of the influenza season 2008-9 in Europe - increasing influenza activity moving from West to East dominated by A(H3N2)

2009 ◽  
Vol 14 (3) ◽  
Author(s):  
N Goddard ◽  
P Zucs ◽  
B Ciancio ◽  
F Plata ◽  
O Hungnes ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Influenza Vaccine ◽  
Northern Hemisphere ◽  
Virus Type ◽  
Influenza Season ◽  
Type A ◽  
Neuraminidase Inhibitors ◽  
Influenza Activity

The influenza season 2008-9 started in week 49 of 2008 and is so far characterised by influenza virus type A subtype H3N2. Isolates of this subtype that were tested proved susceptible to neuraminidase inhibitors, but resistant to M2 inhibitors. The circulating A(H3N2) viruses are antigenically similar to the component in the current northern hemisphere influenza vaccine.

Antigenic and genomic characterization of human influenza A and B viruses circulating in Argentina after the introduction of influenza A(H1N1)pdm09

2014 ◽  
Vol 63 (12) ◽  
pp. 1626-1637 ◽  
Author(s):  
Mara L. Russo ◽  
Andrea V. Pontoriero ◽  
Estefania Benedetti ◽  
Andrea Czech ◽  
Martin Avaro ◽  
...  
Keyword(s):  
Southern Hemisphere ◽  
Influenza A ◽  
Vaccine Virus ◽  
Influenza Viruses ◽  
World Health ◽  
Influenza Surveillance ◽  
Human Influenza ◽  
Surveillance Network ◽  
Influenza A H1n1 ◽  
Health Organization

This study was conducted as part of the Argentinean Influenza and other Respiratory Viruses Surveillance Network, in the context of the Global Influenza Surveillance carried out by the World Health Organization (WHO). The objective was to study the activity and the antigenic and genomic characteristics of circulating viruses for three consecutive seasons (2010, 2011 and 2012) in order to investigate the emergence of influenza viral variants. During the study period, influenza virus circulation was detected from January to December. Influenza A and B, and all current subtypes of human influenza viruses, were present each year. Throughout the 2010 post-pandemic season, influenza A(H1N1)pdm09, unexpectedly, almost disappeared. The haemagglutinin (HA) of the A(H1N1)pdm09 viruses studied were segregated in a different genetic group to those identified during the 2009 pandemic, although they were still antigenically closely related to the vaccine strain A/California/07/2009. Influenza A(H3N2) viruses were the predominant strains circulating during the 2011 season, accounting for nearly 76 % of influenza viruses identified. That year, all HA sequences of the A(H3N2) viruses tested fell into the A/Victoria/208/2009 genetic clade, but remained antigenically related to A/Perth/16/2009 (reference vaccine recommended for this three-year period). A(H3N2) viruses isolated in 2012 were antigenically closely related to A/Victoria/361/2011, recommended by the WHO as the H3 component for the 2013 Southern Hemisphere formulation. B viruses belonging to the B/Victoria lineage circulated in 2010. A mixed circulation of viral variants of both B/Victoria and B/Yamagata lineages was detected in 2012, with the former being predominant. A(H1N1)pdm09 viruses remained antigenically closely related to the vaccine virus A/California/7/2009; A(H3N2) viruses continually evolved into new antigenic clusters and both B lineages, B/Victoria/2/87-like and B/Yamagata/16/88-like viruses, were observed during the study period. The virological surveillance showed that the majority of the circulating strains during the study period were antigenically related to the corresponding Southern Hemisphere vaccine strains except for the 2012 A(H3N2) viruses.

scholarly journals Spotlight influenza: The 2019/20 influenza season and the impact of COVID-19 on influenza surveillance in the WHO European Region

2021 ◽  
Vol 26 (40) ◽  
Author(s):  
Cornelia Adlhoch ◽  
Miriam Sneiderman ◽  
Oksana Martinuka ◽  
Angeliki Melidou ◽  
Nick Bundle ◽  
...  
Keyword(s):  
Influenza A ◽  
Influenza Season ◽  
Healthcare Access ◽  
World Health ◽  
European Region ◽  
Influenza Surveillance ◽  
Influenza B ◽  
Rapid Reduction ◽  
Influenza Activity ◽  
The Impact

Background Annual seasonal influenza activity in the northern hemisphere causes a high burden of disease during the winter months, peaking in the first weeks of the year. Aim We describe the 2019/20 influenza season and the impact of the COVID-19 pandemic on sentinel surveillance in the World Health Organization (WHO) European Region. Methods We analysed weekly epidemiological and virological influenza data from sentinel primary care and hospital sources reported by countries, territories and areas (hereafter countries) in the European Region. Results We observed co-circulation of influenza B/Victoria-lineage, A(H1)pdm09 and A(H3) viruses during the 2019/20 season, with different dominance patterns observed across the Region. A higher proportion of patients with influenza A virus infection than type B were observed. The influenza activity started in week 47/2019, and influenza positivity rate was ≥ 50% for 2 weeks (05–06/2020) rather than 5–8 weeks in the previous five seasons. In many countries a rapid reduction in sentinel reports and the highest influenza activity was observed in weeks 09–13/2020. Reporting was reduced from week 14/2020 across the Region coincident with the onset of widespread circulation of SARS-CoV-2. Conclusions Overall, influenza type A viruses dominated; however, there were varying patterns across the Region, with dominance of B/Victoria-lineage viruses in a few countries. The COVID-19 pandemic contributed to an earlier end of the influenza season and reduced influenza virus circulation probably owing to restricted healthcare access and public health measures.

scholarly journals Late season interim estimates of influenza vaccine effectiveness reliably predict end of season estimates in Victoria, Australia, 2007 to 2012

2013 ◽  
Vol 18 (41) ◽  
Author(s):  
S G Sullivan ◽  
H Kelly
Keyword(s):  
Influenza Vaccine ◽  
World Health Organization ◽  
Influenza A ◽  
Vaccine Effectiveness ◽  
Strain Selection ◽  
World Health ◽  
Percentage Points ◽  
The World ◽  
Influenza Activity ◽  
Health Organization

Twice each year the World Health Organization makes a recommendation for the composition of the influenza vaccine, based on circulating strains of influenza A(H3N2), A(H1N1) and B. Strain selection has always been based on immunogenicity studies with limited human data. Immunogenicity can be considered as a proxy for vaccine effectiveness (VE). However, only interim VE estimates for the target hemisphere can be considered in time for the strain selection meeting. Using surveillance data from Victoria, Australia, we retrospectively estimated and compared interim and final VE estimates for 2007 to 2012. In general, interim estimates were within five percentage points of final estimates. However, estimates made too early or in years of low influenza activity may be unreliable.

Absenteeism in schools during the 2009 influenza A(H1N1) pandemic: a useful tool for early detection of influenza activity in the community?

2011 ◽  
Vol 140 (7) ◽  
pp. 1328-1336 ◽  
Author(s):  
E. O. KARA ◽  
A. J. ELLIOT ◽  
H. BAGNALL ◽  
D. G. F. FOORD ◽  
R. PNAISER ◽  
...  
Keyword(s):  
Syndromic Surveillance ◽  
Influenza A ◽  
Laboratory Data ◽  
Influenza Surveillance ◽  
Surveillance Systems ◽  
H1n1 Pandemic ◽  
School Absenteeism ◽  
Sentinel Network ◽  
Influenza A H1n1 ◽  
Influenza Activity

SUMMARYCertain influenza outbreaks, including the 2009 influenza A(H1N1) pandemic, can predominantly affect school-age children. Therefore the use of school absenteeism data has been considered as a potential tool for providing early warning of increasing influenza activity in the community. This study retrospectively evaluates the usefulness of these data by comparing them with existing syndromic surveillance systems and laboratory data. Weekly mean percentages of absenteeism in 373 state schools (children aged 4–18 years) in Birmingham, UK, from September 2006 to September 2009, were compared with established syndromic surveillance systems including a telephone health helpline, a general practitioner sentinel network and laboratory data for influenza. Correlation coefficients were used to examine the relationship between each syndromic system. In June 2009, school absenteeism generally peaked concomitantly with the existing influenza surveillance systems in England. Weekly school absenteeism surveillance would not have detected pandemic influenza A(H1N1) earlier but daily absenteeism data and the development of baselines could improve the timeliness of the system.

scholarly journals Heterogeneous influenza activity across Europe during the winter of 2002-2003

2003 ◽  
Vol 8 (12) ◽  
pp. 230-239 ◽  
Author(s):  
W J Paget ◽  
T J Meerhoff ◽  
H Rebelo de Andrade ◽  
Keyword(s):  
Influenza Vaccine ◽  
Influenza A ◽  
Historical Data ◽  
Slovak Republic ◽  
Incidence Rates ◽  
Clinical Activity ◽  
Influenza B ◽  
The United Kingdom ◽  
Influenza Activity ◽  
Virus Strains

Influenza activity varied across Europe during the 2002-2003 season both in terms of the intensity of clinical activity and the circulating virus types/subtypes. Influenza B was generally predominant in the 'western' parts of Europe (Portugal, Spain, the United Kingdom and Ireland) and influenza A (H3N2) in the 'central' and 'eastern´ areas (Germany, Italy, Denmark, Switzerland, Poland, Slovenia, the Slovak Republic, the Netherlands). A number of countries experienced mixed seasons, first experiencing activity associated with influenza B and then with influenza A (Belgium, France and Spain). Generally, countries where influenza B was predominant had low (compared to historical data) levels of intensity (a mild season) and longer periods of influenza activity compared to countries where influenza A (H3N2) was predominant. A number of countries, all where influenza A (H3N2) was predominant, reported high levels of intensity compared to historical data: the Czech Republic, Denmark, Germany and Poland. In the six countries where age-specific incidence rates were available, the highest rates were observed among those aged 0-14 years. The influenza virus strains circulating in Europe had a good match with the virus strains in the influenza vaccine. A small number of isolates (A/Fujian/411/2002 (H3N2)-like) were reported at the end of the season that had a reduced reactivity to anti-sera of the vaccine strain. The composition of the 2003-2004 influenza vaccine is the same as during the 2002-2003 season.

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 The spatiotemporal characteristics of influenza A and B in the WHO European Region: can one define influenza transmission zones in Europe?

2017 ◽  
Vol 22 (35) ◽  
Author(s):  
Saverio Caini ◽  
Wladimir J Alonso ◽  
Clotilde El-Guerche Séblain ◽  
François Schellevis ◽  
John Paget
Keyword(s):  
Influenza A ◽  
Western Europe ◽  
Control Measures ◽  
World Health ◽  
European Region ◽  
Influenza B ◽  
Influenza Activity ◽  
Influenza Transmission ◽  
Prevention And Control Measures ◽  
Health Organization

We aimed to assess the epidemiology and spatiotemporal patterns of influenza in the World Health Organization (WHO) European Region and evaluate the validity of partitioning the Region into five influenza transmission zones (ITZs) as proposed by the WHO. We used the FluNet database and included over 650,000 influenza cases from 2000 to 2015. We analysed the data by country and season (from July to the following June). We calculated the median proportion of cases caused by each virus type in a season, compared the timing of the primary peak between countries and used a range of cluster analysis methods to assess the degree of overlap between the WHO-defined and data-driven ITZs. Influenza A and B caused, respectively, a median of 83% and 17% cases in a season. There was a significant west-to-east and non-significant (p = 0.10) south-to-north gradient in the timing of influenza activity. Typically, influenza peaked in February and March; influenza A earlier than influenza B. Most countries in the WHO European Region would fit into two ITZs: ‘Western Europe’ and ‘Eastern Europe’; countries bordering Asia may be better placed into extra-European ITZs. Our findings have implications for the presentation of surveillance data and prevention and control measures in this large WHO Region.

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