Giuseppe
Emeritus
[Source: EuroFlu, full page: (LINK). Edited.]
EuroFlu - Weekly Electronic Bulletin - Week 48 : 25/11/2013-01/12/2013 - 06 December 2013, Issue No. 507
Influenza detections still sporadic in Europe
Summary, week 48/2013
For a description of influenza surveillance in the WHO European Region see below.
Virological surveillance for influenza
During week 48/2013 the number of influenza detections in the Region remained low.
Cumulatively, 6371 specimens from sentinel and non-sentinel sources were tested for influenza during the week, 94(1.5%) of which were positive: 65 (69%) for influenza A and 29 (31%) for influenza B (Fig. 1 and 2).
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Of the 40 influenza A viruses that were subtyped during week 48/2013, 11 (28%) were A(H1N1)pdm09 and 29 (72%) A(H3N2) (Fig. 2a).
Since the beginning of the season (week 40/2013), sentinel and non-sentinel sources have yielded 528 influenza detections: 377 (71%) were influenza A viruses and 151 (29%) influenza B.
Of the 233 influenza A viruses that have been subtyped, 104 (45%) were A(H1N1)pdm09 and 129 (55%) were A(H3N2) (Fig. 2b).
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Owing to the low number of viruses detected in week 48/2013, only 1 country (Italy) reported a dominant virus, influenza A, subtype H3N2, as shown in 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, 3 countries (Germany, Portugal and the United Kingdom (England)) have characterized 11 influenza viruses antigenically:
The 12 A(H3N2) viruses belonged to subgroup 3C, represented by A/Texas/50/2012 in the A/Perth/16/2009, A(H3) clade; the 15 A(H1N1)pdm09 viruses belonged to genetic group 6, represented by A/St Petersburg/27/2011; the 2 influenza B viruses 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 21 influenza A(H1N1)pdm09, 12 influenza A(H3N2) and 2 influenza B viruses for susceptibility to oseltamivir and zanamivir. All showed susceptibility to both drugs.
The 12 influenza A(H1N1)pdm09 and 8 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 48/2013 the European countries making reports all indicated low influenza activity (Map 2) and 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 pre-season levels in all countries reporting clinical data during week 48/2013.
(?)
The number of ILI and ARI cases testing positive for influenza in the Region remained low. Only 32 sentinel samples tested positive for influenza during week 48/2013, reported mainly by a few western European countries.
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32 (4%) of the 811 specimens collected from sentinel sources tested positive for influenza, with the majority being influenza A, during week 48/2013. 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 48/2013 was 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 146 SARI samples collected in Armenia, Belarus, Georgia, Kazakhstan, Kyrgyzstan, the Republic of Moldova, Romania, the Russian Federation and Ukraine tested positive for influenza during week 48/2013. Click here for a detailed overview in table format.
(?)
Since week 40/2013, Ireland, Sweden and the United Kingdom reported 19 hospitalized laboratory-confirmed influenza cases, with 8 of them being influenza B, 4 A(H1N1)pdm09 and 7 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.
Respiratory syncytial virus (RSV)
Based on the data presented by countries reporting on RSV, the positivity rate has been gradually increasing since week 40/2013 (see Country data and graphs for individual country data).
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 48/2013 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: 21 samples were tested for Influenza A and B - none of them were positive. 2 samples were positive for RNA hRSV, 1 sample - positive for RNA Rhinovirus, 1 - positive for RNA hRhinovirus and hParainfluenza type 1 and 1- positive for hParainfluenza type 1.
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EuroFlu - Weekly Electronic Bulletin - Week 48 : 25/11/2013-01/12/2013 - 06 December 2013, Issue No. 507
Influenza detections still sporadic in Europe
Summary, week 48/2013
- Consultation rates for influenza-like illness (ILI) and acute respiratory infection (ARI) in outpatient clinics and hospitalizations due to severe acute respiratory infection (SARI) remain at low levels throughout the WHO European Region.
- Several countries reported sporadic detections of influenza A(H3N2), influenza B and influenza A(H1N1)pdm09.
- The percentage of sentinel samples that tested positive for influenza in week 48/2013 (4%) remained low, as is common for this time of year, while respiratory syncytial virus detections have slowly increased since week 40/2013.
For a description of influenza surveillance in the WHO European Region see below.
Virological surveillance for influenza
During week 48/2013 the number of influenza detections in the Region remained low.
Cumulatively, 6371 specimens from sentinel and non-sentinel sources were tested for influenza during the week, 94(1.5%) of which were positive: 65 (69%) for influenza A and 29 (31%) for influenza B (Fig. 1 and 2).
________
________
Of the 40 influenza A viruses that were subtyped during week 48/2013, 11 (28%) were A(H1N1)pdm09 and 29 (72%) A(H3N2) (Fig. 2a).
Since the beginning of the season (week 40/2013), sentinel and non-sentinel sources have yielded 528 influenza detections: 377 (71%) were influenza A viruses and 151 (29%) influenza B.
Of the 233 influenza A viruses that have been subtyped, 104 (45%) were A(H1N1)pdm09 and 129 (55%) were A(H3N2) (Fig. 2b).
________
________
(?)
Owing to the low number of viruses detected in week 48/2013, only 1 country (Italy) reported a dominant virus, influenza A, subtype H3N2, as shown in 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, 3 countries (Germany, Portugal and the United Kingdom (England)) have characterized 11 influenza viruses antigenically:
- 9 were A(H1N1)pdm09 viruses (A/California/7/2009 (H1N1)-like) and
- 2 B/Yamagata/16/88 lineage viruses:
- 1 B/Massachusetts/2/2012-like and
- 1 B/Wisconsin/1/2010-like.
The 12 A(H3N2) viruses belonged to subgroup 3C, represented by A/Texas/50/2012 in the A/Perth/16/2009, A(H3) clade; the 15 A(H1N1)pdm09 viruses belonged to genetic group 6, represented by A/St Petersburg/27/2011; the 2 influenza B viruses 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 21 influenza A(H1N1)pdm09, 12 influenza A(H3N2) and 2 influenza B viruses for susceptibility to oseltamivir and zanamivir. All showed susceptibility to both drugs.
The 12 influenza A(H1N1)pdm09 and 8 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 48/2013 the European countries making reports all indicated low influenza activity (Map 2) and 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 pre-season levels in all countries reporting clinical data during week 48/2013.
(?)
The number of ILI and ARI cases testing positive for influenza in the Region remained low. Only 32 sentinel samples tested positive for influenza during week 48/2013, reported mainly by a few western European countries.
_________
________
32 (4%) of the 811 specimens collected from sentinel sources tested positive for influenza, with the majority being influenza A, during week 48/2013. Click here for a detailed overview in a table format.
________
Hospital surveillance for SARI
The number of SARI hospitalizations during week 48/2013 was 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 146 SARI samples collected in Armenia, Belarus, Georgia, Kazakhstan, Kyrgyzstan, the Republic of Moldova, Romania, the Russian Federation and Ukraine tested positive for influenza during week 48/2013. Click here for a detailed overview in table format.
(?)
Since week 40/2013, Ireland, Sweden and the United Kingdom reported 19 hospitalized laboratory-confirmed influenza cases, with 8 of them being influenza B, 4 A(H1N1)pdm09 and 7 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.
Respiratory syncytial virus (RSV)
Based on the data presented by countries reporting on RSV, the positivity rate has been gradually increasing since week 40/2013 (see Country data and graphs for individual country data).
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 48/2013 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: 21 samples were tested for Influenza A and B - none of them were positive. 2 samples were positive for RNA hRSV, 1 sample - positive for RNA Rhinovirus, 1 - positive for RNA hRhinovirus and hParainfluenza type 1 and 1- positive for hParainfluenza type 1.
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