Giuseppe
Emeritus
[Source: EuroFlu, full page: (LINK). Extracts.]
EuroFlu - Weekly Electronic Bulletin, Week 45 : 04/11/2013-10/11/2013, 15 November 2013, Issue No. 504
Influenza activity remains at preseason levels in Europe
Summary, week 45/2013
For a description of influenza surveillance in the WHO European Region see below.
Virological surveillance for influenza
Cumulatively, 4488 specimens from sentinel and non-sentinel sources were tested for influenza during week 45/2013, 54 (1.2%) of which were positive: 43 (80%) for influenza A and 11 (20%) for influenza B (Fig. 1 and 2).
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Of the 29 influenza A viruses that were subtyped during week 45/2013, 16 (55%) were A(H1N1)pdm09 and 13 (45%) A(H3N2) (Fig. 2a).
Since the beginning of the season (week 40/2013), 279 influenza viruses from sentinel and non-sentinel sources have been detected and typed, with influenza A being predominant: cumulatively, 205 (73%) viruses were influenza A and 74 (27%)influenza B.
Of the 131 influenza A viruses that have been subtyped, 63 (48%) were A(H1N1)pdm09 and 68 (52%) were A(H3N2) (Fig. 2b).
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Since the beginning of the season, the number of influenza detections in reporting countries has remained too low to allow inference of any dominant virus; consequently 40 countries reported ?none? in the dominant virus type category for week 45/2013 (Map 1).
Virus strain characterizations
Circulating influenza viruses are assessed each season for their antigenic and genetic characteristics, to determine the extent of their antigenic similarity to the viruses included in the seasonal influenza vaccine, and determine the prevalence of mutations that affect pathogenicity or are associated with susceptibility to antiviral drugs.
Since week 40/2013, 2 countries (Germany and United Kingdom (England)) have characterized 3 influenza viruses antigenically: all were A(H1N1)pdm09 viruses (A/California/7/2009 (H1N1)-like).
4 countries (Denmark, Finland, Norway and Spain) have characterized 11 influenza viruses genetically: 8 A(H3N2), 2 A(H1N1)pdm09 and 1 influenza B virus (Yamagata lineage).
Eight A(H3N2) viruses belonged to the subgroup (3C) represented by A/Texas/50/2012 in the A/Perth/16/2009, A(H3) clade; 2 A(H1N1)pdm09 belonged to the genetic group 6 represented by A/St Petersburg/27/2011 in the A(H1N1)pdm09 clade; 1 influenza B virus belonged to clade 2 represented by B/Massachusetts/02/2012 in the B(Yamagata) lineage.
Since week 40/2013, 2 countries (Spain and Sweden) have screened 3 influenza A(H1N1)pdm09 viruses for susceptibility to oseltamivir, zanamivir, and to adamantanes. All showed susceptibility to oseltamivir and zanamivir, but resistance to adamantanes.
For the 2013/2014 northern hemisphere influenza season, WHO recommended inclusion of A/California/7/2009 (H1N1)pdm09-like, A/Texas/50/2012 (H3N2)-like (an egg-adapted virus antigenically like the cell-propagated prototype virus A/Victoria/361/2011) and B/Massachusetts/2/2012-like (Yamagata lineage) viruses in vaccines (see the WHO headquarters web site).
Outpatient surveillance for influenza-like illness (ILI) and/or acute respiratory infection (ARI)
Similarly to previous weeks, during week 45/2013, all reporting countries in the Region reported low influenza activity (Map 2) mainly stable trends (Map 4) with predominantly no or sporadic influenza activity (Map 3), which resembles the situation in previous seasons at this time of year.
Consultation rates for ILI and/or ARI remained below the national baselines or at preseason levels in all countries reporting clinical data, except the Republic of Moldova, during week 45/2013.
(?)
The number of ILI and ARI cases testing positive for influenza in the Region remained low. Only 11 sentinel samples tested positive, mainly in European Union (EU) countries, during week 45.
Fig. 5 presents historical data on the weekly percentage of influenza positive sentinel ILI/ARI specimens from the previous 4 seasons; the percentage of sentinel ILI/ARI influenza positive samples was not calculated in weeks 40?45 2013, because there were fewer than 20 influenza positive specimens per week.
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11 (1.6%) of the 681 specimens collected from sentinel sources tested positive during week 45/2013, with the majority being influenza A. Click here for a detailed overview in a table format.
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Hospital surveillance for SARI
The number of SARI hospitalizations during week 45/2013 was similar to those in previous weeks, and remained at interseason levels in reporting countries participating in hospital surveillance for SARI in the WHO European Region (Fig. 7). Currently, only 9 countries are reporting on SARI hospitalizations, because Albania, Belgium, Slovakia and Romania have not yet started such reporting for this season.
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Similarly to previous weeks none of the 100 SARI samples collected in Armenia, Belarus, Georgia, Kazakhstan, Kyrgyzstan, Republic of Moldova, Russian Federation and Ukraine tested positive for influenza during week 43/2013. Click here for a detailed overview in table format.
(?)
Since week 40/2013, Ireland, Sweden and the United Kingdom reported 14 hospitalized laboratory-confirmed influenza cases, with 7 of them being influenza B, 3 A(H1N1)pdm09 and 4 A not subtyped. For more information on surveillance of confirmed hospitalized influenza, please see ECDC?s Weekly Influenza Surveillance Overview (WISO) at European Centre for Disease Prevention and Control web site.
EuroMOMO (European Mortality Monitoring Project)
EuroMOMO is a project set up to develop and operate a routine public health mortality monitoring system to detect and measure, on a real-time basis, excess deaths related to influenza and other possible public health threats across 20 European Union (EU) countries.
Pooled analysis of week data for 45/2013 showed that all-cause mortality was within the normal range for all reporting countries. Results of pooled analysis may vary, depending on which countries are included in the weekly analysis. For more information about the EUROMOMO mortality monitoring system please click here).
(?)
Country comments (where available)
Republic of Moldova: 20 sentinel samples were tested for Influenza A and B - none of them were positive. 1 sample was positive for RNA hParainfluenza virus type 1, 1 sample - positive for RNA RSV, 2 - positive for RNA Rhinovirus, and 2 samples - positive for RNA hParainfluenza virus type 3.
Scotland: Virology data from non-sentinel sources for week 45 is incomplete and should be interpreted with caution, due to a data transfer problem from one main laboratory.
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EuroFlu - Weekly Electronic Bulletin, Week 45 : 04/11/2013-10/11/2013, 15 November 2013, Issue No. 504
Influenza activity remains at preseason levels in Europe
Summary, week 45/2013
- During week 45/2013 influenza activity in the WHO European Region remained at preseason levels, but with several countries reporting sporadic detections of influenza A(H1N1)pdm09, A(H3N2) and type-B viruses.
- The influenza positivity rate remained low, which is usual for this time of the year and similar to previous seasons.
- The number of hospitalizations due to severe acute respiratory infection (SARI) remains stable, with none of the cases reported this week positive for influenza virus.
For a description of influenza surveillance in the WHO European Region see below.
Virological surveillance for influenza
Cumulatively, 4488 specimens from sentinel and non-sentinel sources were tested for influenza during week 45/2013, 54 (1.2%) of which were positive: 43 (80%) for influenza A and 11 (20%) for influenza B (Fig. 1 and 2).
________
________
Of the 29 influenza A viruses that were subtyped during week 45/2013, 16 (55%) were A(H1N1)pdm09 and 13 (45%) A(H3N2) (Fig. 2a).
Since the beginning of the season (week 40/2013), 279 influenza viruses from sentinel and non-sentinel sources have been detected and typed, with influenza A being predominant: cumulatively, 205 (73%) viruses were influenza A and 74 (27%)influenza B.
Of the 131 influenza A viruses that have been subtyped, 63 (48%) were A(H1N1)pdm09 and 68 (52%) were A(H3N2) (Fig. 2b).
_________
________
(?)
Since the beginning of the season, the number of influenza detections in reporting countries has remained too low to allow inference of any dominant virus; consequently 40 countries reported ?none? in the dominant virus type category for week 45/2013 (Map 1).
Virus strain characterizations
Circulating influenza viruses are assessed each season for their antigenic and genetic characteristics, to determine the extent of their antigenic similarity to the viruses included in the seasonal influenza vaccine, and determine the prevalence of mutations that affect pathogenicity or are associated with susceptibility to antiviral drugs.
Since week 40/2013, 2 countries (Germany and United Kingdom (England)) have characterized 3 influenza viruses antigenically: all were A(H1N1)pdm09 viruses (A/California/7/2009 (H1N1)-like).
4 countries (Denmark, Finland, Norway and Spain) have characterized 11 influenza viruses genetically: 8 A(H3N2), 2 A(H1N1)pdm09 and 1 influenza B virus (Yamagata lineage).
Eight A(H3N2) viruses belonged to the subgroup (3C) represented by A/Texas/50/2012 in the A/Perth/16/2009, A(H3) clade; 2 A(H1N1)pdm09 belonged to the genetic group 6 represented by A/St Petersburg/27/2011 in the A(H1N1)pdm09 clade; 1 influenza B virus belonged to clade 2 represented by B/Massachusetts/02/2012 in the B(Yamagata) lineage.
Since week 40/2013, 2 countries (Spain and Sweden) have screened 3 influenza A(H1N1)pdm09 viruses for susceptibility to oseltamivir, zanamivir, and to adamantanes. All showed susceptibility to oseltamivir and zanamivir, but resistance to adamantanes.
For the 2013/2014 northern hemisphere influenza season, WHO recommended inclusion of A/California/7/2009 (H1N1)pdm09-like, A/Texas/50/2012 (H3N2)-like (an egg-adapted virus antigenically like the cell-propagated prototype virus A/Victoria/361/2011) and B/Massachusetts/2/2012-like (Yamagata lineage) viruses in vaccines (see the WHO headquarters web site).
Outpatient surveillance for influenza-like illness (ILI) and/or acute respiratory infection (ARI)
Similarly to previous weeks, during week 45/2013, all reporting countries in the Region reported low influenza activity (Map 2) mainly stable trends (Map 4) with predominantly no or sporadic influenza activity (Map 3), which resembles the situation in previous seasons at this time of year.
Consultation rates for ILI and/or ARI remained below the national baselines or at preseason levels in all countries reporting clinical data, except the Republic of Moldova, during week 45/2013.
(?)
The number of ILI and ARI cases testing positive for influenza in the Region remained low. Only 11 sentinel samples tested positive, mainly in European Union (EU) countries, during week 45.
Fig. 5 presents historical data on the weekly percentage of influenza positive sentinel ILI/ARI specimens from the previous 4 seasons; the percentage of sentinel ILI/ARI influenza positive samples was not calculated in weeks 40?45 2013, because there were fewer than 20 influenza positive specimens per week.
_________
________
11 (1.6%) of the 681 specimens collected from sentinel sources tested positive during week 45/2013, with the majority being influenza A. Click here for a detailed overview in a table format.
_________
Hospital surveillance for SARI
The number of SARI hospitalizations during week 45/2013 was similar to those in previous weeks, and remained at interseason levels in reporting countries participating in hospital surveillance for SARI in the WHO European Region (Fig. 7). Currently, only 9 countries are reporting on SARI hospitalizations, because Albania, Belgium, Slovakia and Romania have not yet started such reporting for this season.
_________
_________
Similarly to previous weeks none of the 100 SARI samples collected in Armenia, Belarus, Georgia, Kazakhstan, Kyrgyzstan, Republic of Moldova, Russian Federation and Ukraine tested positive for influenza during week 43/2013. Click here for a detailed overview in table format.
(?)
Since week 40/2013, Ireland, Sweden and the United Kingdom reported 14 hospitalized laboratory-confirmed influenza cases, with 7 of them being influenza B, 3 A(H1N1)pdm09 and 4 A not subtyped. For more information on surveillance of confirmed hospitalized influenza, please see ECDC?s Weekly Influenza Surveillance Overview (WISO) at European Centre for Disease Prevention and Control web site.
EuroMOMO (European Mortality Monitoring Project)
EuroMOMO is a project set up to develop and operate a routine public health mortality monitoring system to detect and measure, on a real-time basis, excess deaths related to influenza and other possible public health threats across 20 European Union (EU) countries.
Pooled analysis of week data for 45/2013 showed that all-cause mortality was within the normal range for all reporting countries. Results of pooled analysis may vary, depending on which countries are included in the weekly analysis. For more information about the EUROMOMO mortality monitoring system please click here).
(?)
Country comments (where available)
Republic of Moldova: 20 sentinel samples were tested for Influenza A and B - none of them were positive. 1 sample was positive for RNA hParainfluenza virus type 1, 1 sample - positive for RNA RSV, 2 - positive for RNA Rhinovirus, and 2 samples - positive for RNA hParainfluenza virus type 3.
Scotland: Virology data from non-sentinel sources for week 45 is incomplete and should be interpreted with caution, due to a data transfer problem from one main laboratory.
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