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EuroFlu - Weekly Electronic Bulletin - Week 15 : 09/04/2012-15/04/2012 - 20 April 2012, Issue N? 442 (edited)
[Source: EuroFlu, full page: (LINK). Edited.]
EuroFlu - Weekly Electronic Bulletin - Week 15 : 09/04/2012-15/04/2012 - 20 April 2012, Issue N? 442
Low and decreasing influenza activity in most countries of the WHO European Region
Current situation: week 15/2012
Outpatient surveillance for ILI and ARI
41 countries reported on trends in clinical activity: 12 stable, 2 increasing and 27 decreasing.
Of the 41 countries reporting on the geographical spread of influenza: 8 reported no activity; 17, sporadic activity; 12, local activity; 1, regional activity; and 3, widespread activity.
All countries reported either medium (5) or low intensity (36).
During week 15/2012 sentinel outpatient clinics collected 482 respiratory specimens, of which 132 (27%) tested positive for influenza viruses, a slight decrease in comparison to the previous week.
Of these positive specimens, 84 (64%) were influenza type A and 48 (37%) were influenza B (Table 1, Fig. 1).
In the 8 countries testing 20 or more sentinel specimens, influenza positivity ranged from 15% to 41%, with a median of 26% (mean: 29%).
Hospital surveillance for SARI
10 countries reported data for hospital-based sentinel surveillance of SARI: Armenia, Belarus, Georgia, Kazakhstan, Kyrgyzstan, the Republic of Moldova, Romania, the Russian Federation, Serbia and Ukraine.
95 respiratory specimens were collected from SARI patients, of which 12 (13%) were positive for influenza: 9 were type A and 3 were type B.
All influenza A viruses were subtyped: 8 as A(H3) and 1 as A(H1)pdm09. (Fig. 2).
Further information on the sentinel SARI surveillance systems represented in the EuroFlu bulletin can be found in ?Overview of sentinel SARI systems in EuroFlu?.
Virological overview
During week 15/2012, 38 countries reported a dominant virus based on both sentinel and non-sentinel detections.
12 countries reported influenza A and/or A(H3N2) as the dominant virus, 1 reported influenza B and 3 reported co-dominance of influenza B with A(H3N2).
22 countries reported that no virus was dominant.
Influenza virus type and subtype detections
Table 1 provides an overview of the influenza virus detections by type and subtype in sentinel ILI/ARI and SARI surveillance for both the current week and the period since week 40/2011.
Table 1. Influenza virus detections in sentinel specimens
[Specimens tested and viruses - Current week (number and %): ILI/ARI ? SARI - Cumulative since week 40 (number and %): ILI/ARI ? SARI]
Of the influenza A viruses, 523 were subtyped: 503 (96%) as A(H3N2) and 20 (4%) as A(H1N1)pdm09.
Since week 40/2011, 39 965 influenza viruses from sentinel and non-sentinel sources have been typed: 36 736 (92%) were influenza A and 3229 (8%) were influenza B.
Of the influenza A viruses, 19 817 were subtyped: 19 003 (96%) as A (H3N2) and 814 (4%) as A(H1N1)pdm09.
Virus strain characterizations
Influenza viruses are monitored each season for antigenic and genetic characteristics, to determine the extent to which they correspond with the viruses included in the seasonal influenza vaccine as well as the occurrence of mutations that affect pathogenicity or that are associated with susceptibility to antiviral drugs.
Since week 40/2011, 17 countries (Austria, the Czech Republic, Denmark, the United Kingdom (England), France, Germany, Greece, Hungary, Italy, Latvia, Portugal, Romania, the Russian Federation, Slovakia, Slovenia, Sweden, Switzerland) have characterized 1699 influenza viruses antigenically (Fig. 3).
16 countries (Austria, Belgium, Denmark, Finland, France, Germany, Greece, Ireland, Italy, Latvia, Norway, Portugal, the Russian Federation, Spain, Sweden, Switzerland) have characterized 1106 influenza viruses genetically (Fig. 4).
# Included in the WHO-recommended composition of influenza virus vaccines for use in the 2011/2012 northern hemisphere influenza season.
* Included in the WHO-recommended composition of influenza virus vaccines for use in the 2012 southern hemisphere influenza season.
Further information
The EuroFlu bulletin describes and comments on influenza activity in the 53 countries in the WHO European Region. Further information can be obtained from the WHO/Europe, WHO headquarters and European Centre for Disease Prevention and Control web sites.
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EuroFlu - Weekly Electronic Bulletin - Week 15 : 09/04/2012-15/04/2012 - 20 April 2012, Issue N? 442
Low and decreasing influenza activity in most countries of the WHO European Region
Current situation: week 15/2012
- This issue is based on data for week 15/2012 reported by 46 Member States in the WHO European Region.
- Consultation rates have decreased in most of the countries with only 2 of them reporting increasing trends.
- The number of specimens tested from both sentinel and non-sentinel sources is decreasing with a slight decrease in the percentage of influenza-positive cases.
- The number of hospitalizations due to severe acute respiratory infection (SARI) is more or less stable with a slight decrease in the influenza-positivity rate.
- Influenza A(H3N2) viruses continue to dominate, with few A(H1N1)pdm09 detections and some influenza B detections.
Outpatient surveillance for ILI and ARI
41 countries reported on trends in clinical activity: 12 stable, 2 increasing and 27 decreasing.
Of the 41 countries reporting on the geographical spread of influenza: 8 reported no activity; 17, sporadic activity; 12, local activity; 1, regional activity; and 3, widespread activity.
All countries reported either medium (5) or low intensity (36).
During week 15/2012 sentinel outpatient clinics collected 482 respiratory specimens, of which 132 (27%) tested positive for influenza viruses, a slight decrease in comparison to the previous week.
Of these positive specimens, 84 (64%) were influenza type A and 48 (37%) were influenza B (Table 1, Fig. 1).
In the 8 countries testing 20 or more sentinel specimens, influenza positivity ranged from 15% to 41%, with a median of 26% (mean: 29%).
Hospital surveillance for SARI
10 countries reported data for hospital-based sentinel surveillance of SARI: Armenia, Belarus, Georgia, Kazakhstan, Kyrgyzstan, the Republic of Moldova, Romania, the Russian Federation, Serbia and Ukraine.
95 respiratory specimens were collected from SARI patients, of which 12 (13%) were positive for influenza: 9 were type A and 3 were type B.
All influenza A viruses were subtyped: 8 as A(H3) and 1 as A(H1)pdm09. (Fig. 2).
Virological overview
During week 15/2012, 38 countries reported a dominant virus based on both sentinel and non-sentinel detections.
12 countries reported influenza A and/or A(H3N2) as the dominant virus, 1 reported influenza B and 3 reported co-dominance of influenza B with A(H3N2).
22 countries reported that no virus was dominant.
Influenza virus type and subtype detections
Table 1 provides an overview of the influenza virus detections by type and subtype in sentinel ILI/ARI and SARI surveillance for both the current week and the period since week 40/2011.
Table 1. Influenza virus detections in sentinel specimens
[Specimens tested and viruses - Current week (number and %): ILI/ARI ? SARI - Cumulative since week 40 (number and %): ILI/ARI ? SARI]
- Specimens tested - 482 - 95 - 34236 - 3963
- Influenza A + B - 132 (27.4%) - 12 (12.6%) - 10557 (30.8%) - 614 (15.5%)
- Influenza A - 84 (63.6%) - 9 (75.0%) - 9331 (88.4%) - 583 (95.0%)
- Influenza B - 48 (36.4%) - 3 (25.0%) - 1226 (11.6%) - 31 (5.1%)
- Influenza A subtyped - 53 - 9 - 8418 - 550
- A (H1N1)pdm09 - 3 (5.7%) - 1 (11.1%) - 158 (1.9%) - 63 (11.5%)
- A (H3N2) - 50 (94.3%) - 8 (88.9%) - 8260 (98.1%) - 486 (88.4%)
- A (H1N1) - 0 (0.0%) - 0 (0.0%) - 0 (0.0%) - 1 (0.2%)
Of the influenza A viruses, 523 were subtyped: 503 (96%) as A(H3N2) and 20 (4%) as A(H1N1)pdm09.
Since week 40/2011, 39 965 influenza viruses from sentinel and non-sentinel sources have been typed: 36 736 (92%) were influenza A and 3229 (8%) were influenza B.
Of the influenza A viruses, 19 817 were subtyped: 19 003 (96%) as A (H3N2) and 814 (4%) as A(H1N1)pdm09.
Virus strain characterizations
Influenza viruses are monitored each season for antigenic and genetic characteristics, to determine the extent to which they correspond with the viruses included in the seasonal influenza vaccine as well as the occurrence of mutations that affect pathogenicity or that are associated with susceptibility to antiviral drugs.
Since week 40/2011, 17 countries (Austria, the Czech Republic, Denmark, the United Kingdom (England), France, Germany, Greece, Hungary, Italy, Latvia, Portugal, Romania, the Russian Federation, Slovakia, Slovenia, Sweden, Switzerland) have characterized 1699 influenza viruses antigenically (Fig. 3).
16 countries (Austria, Belgium, Denmark, Finland, France, Germany, Greece, Ireland, Italy, Latvia, Norway, Portugal, the Russian Federation, Spain, Sweden, Switzerland) have characterized 1106 influenza viruses genetically (Fig. 4).
* Included in the WHO-recommended composition of influenza virus vaccines for use in the 2012 southern hemisphere influenza season.
Further information
The EuroFlu bulletin describes and comments on influenza activity in the 53 countries in the WHO European Region. Further information can be obtained from the WHO/Europe, WHO headquarters and European Centre for Disease Prevention and Control web sites.
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