Giuseppe
Emeritus
[Source: EuroFlu, full page: (LINK). Extracts.]
EuroFlu - Weekly Electronic Bulletin, Week 46 : 11/11/2013-17/11/2013, 22 November 2013, Issue No. 505
Low influenza activity in Europe
Summary, week 46/2013
For a description of influenza surveillance in the WHO European Region see below.
(?)
Virological surveillance for influenza
During week 46/2013 the number of influenza detections in the Region remained low.
Cumulatively, 5585 specimens from sentinel and non-sentinel sources were tested for influenza during week 46/2013, 55 (1%) of which were positive: 35 (63%) for influenza A and 20 (37%) for influenza B (Fig. 1 and 2).
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Of the 22 influenza A viruses that were subtyped during week 46/2013, 12 (55%) were A(H1N1)pdm09 and 10 (45%) A(H3N2) (Fig. 2a).
Since the beginning of the season (week 40/2013), 356 influenza viruses from sentinel and non-sentinel sources have been detected and typed.
Influenza A was predominant: 257 (72%) were influenza A and 99 (28%) influenza B viruses. Of the 165 influenza A viruses that have been subtyped, 82 were A(H1N1)pdm09 and 83 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 category for week 46/2013 (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 8 influenza viruses antigenically: all were A(H1N1)pdm09 viruses (A/California/7/2009 (H1N1)-like).
4 countries (Denmark, Finland, Norway and Sweden) have characterized 16 influenza viruses genetically: 9 A(H3N2), 6 A(H1N1)pdm09 and 1 influenza B virus (Yamagata lineage).
The 9 A(H3N2) viruses belonged to subgroup 3C, represented by A/Texas/50/2012 in the A/Perth/16/2009, A(H3) clade; 6 A(H1N1)pdm09 belonged to genetic group 6, represented by A/St Petersburg/27/2011 in the A(H1N1)pdm09 clade; the influenza B virus belonged to clade 2 represented by B/Massachusetts/02/2012 in the Yamagata lineage.
Since week 40/2013, 4 countries (Norway, Spain, Sweden and United Kingdom (England)) have screened 8 influenza A(H1N1)pdm09, 8 influenza A(H3N2) viruses and 1 influenza B virus for susceptibility to oseltamivir and zanamivir. All showed susceptibility to both drugs. The 5 influenza A(H1N1)pdm09 and 7 influenza A(H3N2) viruses screened for susceptibility to adamantanes were found to be resistant.
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 46/2013, 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 during week 46/2013.
(?)
The number of ILI and ARI cases testing positive for influenza in the Region remained low. Only 1 sentinel sample tested positive for influenza during week 46/2013.
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?46/2013, because there were fewer than 20 influenza positive specimens per week.
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1 (0.1%) of the 778 specimens collected from sentinel sources tested positive for influenza A during week 46/2013. 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 46/2013 was lower than in the preceding week, but similar to those in previous weeks. It remained at interseason levels in reporting countries participating in hospital surveillance for SARI in the WHO European Region (Fig. 7).
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Similarly to previous weeks none of the 128 SARI samples collected in Belarus, Georgia, Kazakhstan, Kyrgyzstan, the Republic of Moldova, Romania, the Russian Federation and Ukraine tested positive for influenza during week 46/2013. Click here for a detailed overview in table format.
(?)
Since week 40/2013, Ireland, Sweden and the United Kingdom reported 15 hospitalized laboratory-confirmed influenza cases, with 7 of them being influenza B, 3 A(H1N1)pdm09 and 5 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 46/2013 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 Rhinovirus and RNA hParainfluenza virus type 1, and 2 - positive for RNA Rhinovirus.
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EuroFlu - Weekly Electronic Bulletin, Week 46 : 11/11/2013-17/11/2013, 22 November 2013, Issue No. 505
Low influenza activity in Europe
Summary, week 46/2013
- Levels of influenza activity in the WHO European Region remained low, with co-circulation of influenza A(H1N1)pdm09, A(H3N2) and type-B viruses reported by countries for week 46/2013.
- The number of specimens testing positive for influenza was low, which is typical for this time of the year and comparable with previous seasons.
- The number of hospitalizations due to severe acute respiratory infection (SARI) was similar to that in the previous week, with none of the cases testing positive for influenza.
For a description of influenza surveillance in the WHO European Region see below.
(?)
Virological surveillance for influenza
During week 46/2013 the number of influenza detections in the Region remained low.
Cumulatively, 5585 specimens from sentinel and non-sentinel sources were tested for influenza during week 46/2013, 55 (1%) of which were positive: 35 (63%) for influenza A and 20 (37%) for influenza B (Fig. 1 and 2).
_________
________
Of the 22 influenza A viruses that were subtyped during week 46/2013, 12 (55%) were A(H1N1)pdm09 and 10 (45%) A(H3N2) (Fig. 2a).
Since the beginning of the season (week 40/2013), 356 influenza viruses from sentinel and non-sentinel sources have been detected and typed.
Influenza A was predominant: 257 (72%) were influenza A and 99 (28%) influenza B viruses. Of the 165 influenza A viruses that have been subtyped, 82 were A(H1N1)pdm09 and 83 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 category for week 46/2013 (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 8 influenza viruses antigenically: all were A(H1N1)pdm09 viruses (A/California/7/2009 (H1N1)-like).
4 countries (Denmark, Finland, Norway and Sweden) have characterized 16 influenza viruses genetically: 9 A(H3N2), 6 A(H1N1)pdm09 and 1 influenza B virus (Yamagata lineage).
The 9 A(H3N2) viruses belonged to subgroup 3C, represented by A/Texas/50/2012 in the A/Perth/16/2009, A(H3) clade; 6 A(H1N1)pdm09 belonged to genetic group 6, represented by A/St Petersburg/27/2011 in the A(H1N1)pdm09 clade; the influenza B virus belonged to clade 2 represented by B/Massachusetts/02/2012 in the Yamagata lineage.
Since week 40/2013, 4 countries (Norway, Spain, Sweden and United Kingdom (England)) have screened 8 influenza A(H1N1)pdm09, 8 influenza A(H3N2) viruses and 1 influenza B virus for susceptibility to oseltamivir and zanamivir. All showed susceptibility to both drugs. The 5 influenza A(H1N1)pdm09 and 7 influenza A(H3N2) viruses screened for susceptibility to adamantanes were found to be resistant.
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 46/2013, 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 during week 46/2013.
(?)
The number of ILI and ARI cases testing positive for influenza in the Region remained low. Only 1 sentinel sample tested positive for influenza during week 46/2013.
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?46/2013, because there were fewer than 20 influenza positive specimens per week.
_________
________
1 (0.1%) of the 778 specimens collected from sentinel sources tested positive for influenza A during week 46/2013. Click here for a detailed overview in a table format.
_________
_________
Hospital surveillance for SARI
The number of SARI hospitalizations during week 46/2013 was lower than in the preceding week, but similar to those in previous weeks. It remained at interseason levels in reporting countries participating in hospital surveillance for SARI in the WHO European Region (Fig. 7).
_________
_________
Similarly to previous weeks none of the 128 SARI samples collected in Belarus, Georgia, Kazakhstan, Kyrgyzstan, the Republic of Moldova, Romania, the Russian Federation and Ukraine tested positive for influenza during week 46/2013. Click here for a detailed overview in table format.
(?)
Since week 40/2013, Ireland, Sweden and the United Kingdom reported 15 hospitalized laboratory-confirmed influenza cases, with 7 of them being influenza B, 3 A(H1N1)pdm09 and 5 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 46/2013 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 Rhinovirus and RNA hParainfluenza virus type 1, and 2 - positive for RNA Rhinovirus.
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