INFLUENZA (11): EUROPE, UK, WHO
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In this posting:
[1] Europe: WHO
[2] UK
******
[1] Europe: WHO
Date: Fri 4 Feb 2011
Source: WHO Regional Office for Europe, EuroFlu: Weekly Electronic
Bulletin [summ., edited]
<http://www.euroflu.org/cgi-files/bulletin_v2.cgi>
High influenza activity across the European Region
--------------------------------------------------
Current situation -- week 4/2011 [24-30 Jan 2011]
-------------------------------------------------
During week 4/2011, 2 countries (Georgia and Luxembourg) reported
very high intensity of influenza activity; 8 reported high intensity,
and 26 reported medium intensity. The geographical spread of influenza
activity was reported to be widespread in 23 countries. Of the 25
countries reporting on the impact of influenza on health care systems,
1 (Georgia) reported severe impact, 10 countries reported moderate
impact and 14, low impact.
Clinical data also indicated increasing influenza activity in much of
the WHO European Region, as 31 countries reported increasing trends in
consultation rates for influenza-like illness (ILI) and/or acute
respiratory infection (ARI). In general, the highest consultation
rates were reported for children aged 0 to 4 and 5 to 14 years. In
contrast, declining clinical trends in ILI were observed in Ireland
and the United Kingdom, and some southern countries (Israel, Malta,
Portugal, and Spain).
Seven countries (Georgia, Kyrgyzstan, Romania, the Republic of
Moldova, the Russian Federation, Serbia and Ukraine) reported clinical
data on SARI (severe ARI) from sentinel hospitals. Hospitalizations
due to SARI have increased during recent weeks in Georgia, Kyrgyzstan,
Romania, the Russian Federation, and Serbia, which also reported
increases in clinical consultation rates for ILI or ARI.
Virological situation -- week 4/2011 [24-30 Jan 2011]
-----------------------------------------------------
Pandemic influenza A(H1N1) 2009 continued to predominate in the
Region. It was reported to be dominant in 19 countries and co-dominant
with influenza B in 13 countries. Influenza B was dominant in 4
countries. Sentinel physicians collected 3656 respiratory specimens,
of which 1691 (46 percent) were positive for influenza virus: of these
1100 (65 percent) were influenza A and 591 (35 percent) were influenza
B. Of the influenza A viruses, 981 were subtyped: 926 (94 percent) as
pandemic A(H1) and 55 (6 percent) as A(H3). In the 31 countries
testing 20 or more sentinel specimens, influenza positivity ranged
from 9 percent to 75 percent, with a median of 50 percent (mean: 45
percent). In addition, 5940 non-sentinel specimens were reported
positive for influenza: 4428 (75 percent) influenza A and 1512 (25
percent) influenza B. Of the influenza A viruses, 3555 were subtyped:
3480 (98 percent) as pandemic A(H1) and 75 (2 percent) as A(H3). Out
of 195 sentinel SARI specimens collected during week 4/2011, 86 (44
percent) tested positive for influenza: 61 (71 percent) were influenza
A, 25 (29 percent) were influenza B. All the influenza A viruses were
subtyped: 59 (97 percent) as pandemic A(H1), and 2 (3 percent) as
A(H3). The percentage of SARI specimens testing positive for influenza
ranged from 10 percent (Ukraine) to 70 percent (Serbia) with a median
of 45 percent (mean: 43 percent).
Respiratory syncytial viruses (RSV) continue to circulate, and were
detected in 18 countries. In 15 of these countries, however, fewer RSV
detections were reported during week 4/2011 than in week 3/2011 [17-23
Jan 2011].
Cumulative virological update -- weeks 40/2010- 4/2011 [4 Oct 2010-30
Jan 2011]
----------------------------------------------------------------------
A total of 38 300 influenza virus detections was reported during this
period, of which 27 460 (72 percent) were influenza A and 10 840 (28
percent) influenza B. Of the influenza A viruses, 18 944 were
subtyped: 18 073 (95 percent) as pandemic influenza A(H1), 869 (5
percent) as influenza A(H3) and 2 as influenza A(H1).
From week 40/2010 to week 4/2011, 377 out of 1959 sentinel SARI
specimens (19 percent) have tested positive for influenza. Of these
influenza viruses: 140 (37 percent) were influenza A and 237 (63
percent) influenza B. Of the influenza A viruses, 127 were subtyped:
117 (92 percent) as pandemic influenza A(H1) and 10 (8 percent) as
influenza A(H3).
Since week 40/2010, 1083 influenza viruses have been characterized
antigenically: 618 were A(H1) pandemic A/California/7/2009
(H1N1)-like; 363 were B/Brisbane/60/2008-like (B/Victoria/2/87
lineage); 79 were A(H3) A/Perth/16/2009 (H3N2)-like; 22 were
B/Florida/4/2006-like (B/Yamagata/16/88 lineage); and 1 was
B/Bangladesh/3333/2007-like (B/Yamagata/16/88 lineage). Based on the
genetic characterization of 165 influenza viruses, 90 belonged to the
pandemic A/California/7/2009 A(H1N1) clade; 4 belonged to the pandemic
A/Christchurch/16/2010 A(H1) clade; 23 belonged to the pandemic A/Hong
Kong/2213/2010 A(H1) clade; 16 were reported as A(H1) pandemic not
attributed to group category but belonging to the recently emerged
A/England/142/2010 subgroup characterized by S185T substitution in the
HA; 5 belonged to the A(H3) clade represented by A/Perth/16/2009; 2
belonged to the A(H3) clade represented by A/Victoria/208/2009; 17
belonged to the subgroup represented by A/Hong Kong/2121/2010 in the
A/Victoria/208/2009 A(H3) clade; 7 belonged to the
B/Bangladesh/3333/2007 clade (Yamagata lineage); and 1 to the
B/Brisbane/60/2008 clade (Victoria lineage).
Since week 40/2010, 3 countries (Italy, Norway, and the United
Kingdom) have screened viruses for resistance to the neuraminidase
inhibitors oseltamivir and zanamivir. The United Kingdom analysed most
of the viruses screened (678). Out of the total of 714 isolates of
pandemic influenza A(H1N1) 2009 viruses that were tested, 688 were
sensitive to both inhibitors and 26 viruses (3.6 percent) carried the
H275Y mutation. These 26 viruses were resistant to oseltamivir but
remained sensitive to zanamivir. One influenza A(H3N2) virus was
tested and found to be sensitive to both inhibitors. All of the 61
influenza B viruses tested for oseltamivir resistance and the 62
tested for zanamivir resistance were found to be sensitive. All 35
pandemic (H1N1) 2009 viruses and 2 A(H3N2) viruses that were screened
for susceptibility to adamantanes were found to be resistant.
Comment
-------
ILI and ARI consultation rates are increasing in much of the WHO
European Region. In week 4/2011 [24-30 Jan 2011], 46 percent of
sentinel ILI/ARI specimens and 44 percent of sentinel SARI specimens
were positive for influenza. Influenza A(H3N2) has substantially
decreased in circulation relative to pandemic influenza A(H1N1) 2009
during the course of the 2010/2011 influenza season. Influenza B
viruses continue to co-circulate. During this week the relative
distribution of influenza types and subtypes in hospitalized SARI
patients appeared similar to that observed from other sentinel and
non-sentinel data sources. There is a notable difference in the
proportion of influenza A to influenza B among viruses from SARI
patients in week 4/2011, when compared to all viruses from SARI
patients for the cumulative 2010/2011 influenza season. This reflects
the recent shift in the relative circulation of influenza A to
influenza B viruses in the Caucasus, central Asia, and Russian
Federation, as most of the countries that are conducting sentinel SARI
surveillance are located in this part of the WHO European Region.
Since the genetic characterization algorithms were put in place for
pandemic influenza A(H1N1) viruses at the start of the 2010/2011
influenza season, a new genetic subgroup has been observed to emerge
that is geographically dispersed and increasing in prevalence. This
genetic subgroup is characterized by an S185T substitution in HA and
is represented by A/England/142/2010. To date, viruses carrying the
S185T substitution remain antigenically similar to the current vaccine
virus A/California/7/2009. At present, 98 percent of antigenically
characterized viruses from the 2010/2011 influenza season are similar
to the viruses included in the 2010/2011 northern hemisphere influenza
vaccines.
******
[2] UK: HPA
Date: Fri 4 Feb 2011
Source: Health Protection Agency (HPA) Report, 5(5) [edited]
<http://www.hpa.org.uk/hpr/archives/2011/news0511.htm#flu>
Influenza activity declining in the UK
--------------------------------------
Influenza activity has been declining in the UK in recent weeks. In
England, community, primary care and secondary care indictors have all
declined from the peak in activity over the Christmas period.
The cumulative number of confirmed influenza deaths has increased but
most of the increase is due to deaths which occurred during the
Christmas and New Year period rather than more recently.
Influenza A(H1N1)2009 has been the predominant virus and continues to
circulate but influenza B, which is mainly affecting children, is now
being reported more frequently than A(H1N1)2009.
The heightened activity in influenza this season is also thought to
have contributed to increases in invasive _Streptococcus pyrogenes_
and _S. pneumoniae_ above the seasonally expected levels [1].
Fatalities have been documented from invasive group A streptococcal
infections implicating influenza co-infection [2].
Another area of concern is that in contrast to the 2009/2010 season,
low-level community transmission of oseltamivir-resistant strains of
influenza A(H1N1)2009 virus has been reported which, if it increases,
may have implications for antiviral prescribing recommendations [3].
The headline influenza indicators reported in the 3 Feb 2011 edition
of the HPA National Weekly Influenza Bulletin were [4] included the
following:
- in week 4 (ending 30 Jan 2011) the weekly ILI consultation rate
decreased in England (24.1 per 100 000), Scotland (45.7 per 100 000),
Wales (24.7 per 100 000), and Northern Ireland (76.2 per 100 000). GP
consultation rates are below baseline levels in England, Wales, and
Scotland.
- 28 of 128 (21.96 percent) specimens from patients with ILI
presenting to sentinel GPs in England in week 4 were reported as
positive for influenza;
- since week 36, 395 UK deaths associated with influenza infection
have been reported. Excess all-cause mortality continues to be
observed in week 3;
- 45 H1N1 (2009) viruses have been found to carry the H275Y mutation,
which confers resistance to the antiviral drug oseltamivir.
References
----------
1. Zakikhany K, Degail MA, Lamanghi T, et al: Increase in invasive
_Streptococcus pyogenes_ and _Streptococcus pneumoniae_ infections in
England, December 2010 to January 2011. Euro Surveill. 16(5), 2011.
Rapid communication [available at
<http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=19785>].
2. Scaber J, Saeed S, Ihekweazu C, et al: Group A streptococcal
infections during the seasonal influenza outbreak 2010/11 in South
East England. Euro Surveill. 16(5), 2011. Rapid communication
[available at
<http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=19780>].
3. Lackenby A, Gilad JM, Pebody R, et al: Continued emergence and
changing epidemiology of oseltamivir-resistant influenza A(H1N1)2009
virus, United Kingdom, Winter 2010/11. Euro Surveill. 16(5), 2011.
Rapid communication [available at
<http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=19784>].
4. HPA Weekly National Influenza Report, 3 Feb 2011. Available from
the HPA website at
<http://www.hpa.org.uk/web/HPAweb&HPAwebStandard/HPAweb_C/1287147913271>.
--
Communicated by:
ProMED-mail
<promed@promedmail.org>
[[In brief; influenza activity is increasing in most countries in the
region, and 23 of them report widespread influenza activity. The
outbreak continues to progress west to east, with decline in the UK. A
slightly higher percentage of specimens from patients with ILI
(influenza-like illness) and/or acute respiratory infections (ARI),
were positive for influenza in week 4/2011 (24-30 Jan 2011) than
previously. Most antigenically characterized viruses are similar to
the viruses included in the 2010/2011 northern hemisphere influenza
vaccines. Influenza A(H3N2) has substantially decreased in circulation
relative to pandemic influenza A(H1N1) 2009 during the course of the
2010/2011 influenza season. The previous seasonal (H1N1) virus has
virtually disappeared. In the UK the heightened activity in influenza
this season is thought to have contributed to increases in invasive
_Streptococcus pyrogenes_ and _S. pneumoniae_
A new genetic subgroup has emerged that is geographically dispersed
and increasing in prevalence. This genetic subgroup is characterized
by an S185T substitution in HA. To date, viruses carrying the S185T
substitution remain antigenically similar to the current vaccine virus
A/California/7/2009.
Low-level community transmission of oseltamivir-resistant strains of
influenza A(H1N1)2009 virus has been reported in the UK which, if it
increases, may have implications for antiviral prescribing
recommendations. - Mod.CP]]
[see also:
Influenza (10): Europe 20110129.0351
Influenza (09): WHO update 126 20110128.0337
Influenza (08): Europe 20110121.0247
Influenza (07): Israel 20110119.0232
Influenza (06): Europe, comment 20110115.0175
Influenza (05): WHO update 125 20110115.0171
Influenza (04): Europe 20110114.0163
Influenza (03): Egypt, France 20110111.0128
Influenza (02): UK 20110107.0086
Influenza: Egypt 20110103.0029]
................................................. cp/mj/jw
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