Get documents about "NPHS Weekly Influenza Surveillance Report
Document Sample
NPHS Weekly Influenza Surveillance Report
Wednesday 12 August 2009
Summary
The clinical consultation rate for influenza in Wales reported through the GP
Surveillance of Infections Scheme decreased during week 32 to 49.4 per 100,000 (from
69.9 per 100,000 in week 31) this is above the baseline level threshold of 25
consultations per 100,000 practice population and would be considered to be normal
seasonal activity for the winter period.
During week 32 (week ending 09/08/09), ten samples from sentinel GPs were submitted for
virological testing (see table 2), one of which tested positive for influenza A(H1N1)v (patient
aged 1 – 4yrs, from South Wales) and one tested positive for rhinovirus (patient aged 15 –
24yrs from North Wales). Since week 25 (week ending 21/06/09), 55 samples have been
submitted by sentinel GPs for testing (including nine from the Out of Hours Service), four of
these samples have tested positive for swine influenza A(H1N1)v and four have tested
positive for rhinovirus.
As at 10am 12/08/09, 100 laboratory-confirmed cases of swine influenza A(H1N1)v have
been reported by NPHS Wales Health Protection Teams in 20 LHB areas (table 3). Thirty-
three of these cases have been admitted to hospital, 31 of whom have now been discharged.
During week 31 (week ending 02/08/09) the RCGP influenza like illness rate for England
decreased from 137.0 per 100,000 to 42.0 per 100,000, which is above the baseline
threshold of 30 consultations per 100,000. In Northern Ireland the combined influenza and
influenza like illness consultation rate increased from 130.4 per 100,000 to 142.5 per 100,000
(thresholds have not yet been set). In Scotland the GP influenza consultation rate decreased
slightly from 55 per 100,000 to 48.4 per 100,000, during week 31. Updates for UK countries
are produced on a weekly basis each Thursday and are available from:
http://www.hpa.org.uk/web/HPAweb&Page&HPAwebAutoListName/Page/1243928258560
ECDC report that as of 28 July, the cumulative number of swine influenza cases in the EU
and EFTA countries is 34,152 of which 12,470 have occurred in the UK. ECDC report that
there have been 54 deaths throughout Europe attributed to swine influenza A(H1N1)v, 40 of
these occurred in the UK, nine in Spain, one in Hungary, one in Belgium, one in France, one
in Ireland and one in the Netherlands. Thirty of the 31 EU and EEA/EFTA countries have now
reported cases of swine influenza A(H1N1)v. Latest data (week 31) from Euroflu, indicates
most European countries are reporting moderate – low activity. Wales, England, Malta and
Austria report widespread activity, Italy reports geographic spread at a regional level, all other
countries report local/ sporadic/ no geographical spread. Pandemic influenza A(H1N1)v
continues to be the dominant influenza virus, accounting for 76% of the 85 influenza A
detections in European sentinel physician influenza A positive samples and 80% of the 2,032
European non-sentinel physician influenza A positive samples. Latest European level
surveillance data is published each Friday at 12pm on: http://www.euroflu.org/
The rolling seven day consultation rate for influenza from the NPHS Wales Rapid
Surveillance of Influenza using Audit+ (containing data submitted up to 12/08/09 from 72% of
General Practices in Wales) has decreased compared to the rate reported 7 days ago (from
89.0 per 100,000 to 55.3 per 100,000). Consultation rates are between 25 and 100 per
100,000 in all 22 LHB areas in Wales.
Data from the NPHS Wales Specialist Virology Centre indicate that out of 354 samples from
patients with respiratory illness (from hospital and the community) submitted for testing
between 20/07/09 – 11/08/09, 22 tested positive for influenza A(H1N1)v, 31 samples tested
positive for rhinovirus, 6 samples tested positive for parainfluenza and two samples tested
positive for RSV. This suggests that while influenza A(H1N1)v is the dominant influenza virus,
other respiratory viruses are also presently in circulation.
Daily influenza surveillance updates are available from the NPHS Wales Rapid Influenza
Surveillance internet site: http://www.wales.nhs.uk/sites3/page.cfm?orgid=457&pid=38241
-1-
Figure 1. Clinical consultation rate per 100,000 practice population in Welsh sentinel
practices (as of 12/08/09).
1
1999 - 2000 2007 - 2008 2008 - 2009
200
180
160
Consultation rate per 100,000
Higher than average seasonal activity
140
120
100
Normal seasonal activity
80
60
40
20 Baseline activity
0
40
42
44
46
48
50
52
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
32
34
36
38
Week
Table 1. Age specific consultations (per 100,000) for influenza in Welsh sentinel
practices, week 27 2009 – week 32 2009 (as of 12/08/09).
Age Week
group 27 28 29 30 31 32
Age specific
0-4 0.0 34.8 58.0 189.0 92.1 86.6
consultation rate
5 - 14 6.3 18.4 9.4 104.9 56.4 43.4 during week 32
15 - 24 11.7 27.0 66.7 109.6 110.2 61.9 were highest
25 - 34 9.2 16.7 57.9 129.2 106.9 97.2 among patients
35 - 44 7.5 12.0 40.5 91.2 58.4 48.1 aged 25 - 34 yrs
45 - 64 1.8 17.2 34.6 75.0 74.2 37.9
65 + 1.9 1.9 9.9 45.6 24.7 19.3
Total 5.1 15.8 36.0 92.8 69.9 49.4
Figure 2. Historical clinical consultation rate per 100,000 practice population in Welsh
sentinel practices (week 41 1996 – week 32 2009).
450
Epidemic activity
400
Consultation rate per 100,000
350
300
250 Higher than average
seasonal (winter) activity
200
150
100
Normal seasonal
50 activity (winter)
0
October 1996
April 1997
October 1997
April 1998
October 1998
April 1999
October 1999
April 2000
October 2000
April 2001
October 2001
April 2002
October 2002
April 2003
October 2003
April 2004
October 2004
April 2005
October 2005
April 2006
October 2006
April 2007
October 2007
April 2008
October 2008
March 2009
-2-
Enhanced virological surveillance for influenza and respiratory viruses
Table 2. Specimens submitted for virological surveillance (as at 12/08/09, by week of
sample collection, combined results from GP sentinel surveillance and Out of Hours
GP sentinel surveillance) .
Week Specimens Specimens Positive identifications
submitted tested influenza A influenza
RSV parainfluenza rhinovirus
Total A A(H1N1)v* B
26 3 3 0 0 0 0 0 0
27 4 4 1 1 0 0 0 0
28 10 10 0 0 0 0 0 0
29 13 13 1 1 0 0 0 1
30 4 4 0 0 0 0 0 0
31 11 11 1 1 0 0 0 2
32 10 10 1 1 0 0 0 1
Total 55 55 4 4 0 0 0 4
* swine influenza A(H1N1)v
During week 32 (week ending 09/08/09) ten samples were submitted by sentinel GPs for testing,
one of which tested positive for swine influenza A(H1N1)v and one of which tested positive for
rhinovirus. Since week 26 (22 Jun 2009) 55 samples have been received and tested from sentinel
GPs (including nine Out of Hours GP Service sample). Four samples have tested positive for
influenza A and were further identified as swine influenza A(H1N1)v and four samples have
tested positive for rhinovirus.
-3-
Summary of Confirmed swine influenza A(H1N1)v cases in Wales
Table 3. Confirmed Swine influenza A(H1N1)v cases reported to NPHS Wales, as at
12/08/09, by LHB area of residence.
LHB Laboratory
confirmed cases
Anglesey 2
Blaenau Gwent 2
Bridgend 1
Caerphilly 7
Cardiff 26
Carmarthen 3
Ceredigion 3
Conwy 2
Denbighshire 4
Merthyr 5
Monmouthshire 5
Neath Port Talbot 2
Newport 16
Pembrokeshire 2
Powys 4
RCT 3
Swansea 8
Torfaen 2
Vale of Glamorgan 2
Wrexham 1
Total 100
Tables 4 and 5. Confirmed Swine influenza A(H1N1)v cases reported to NPHS Wales,
as at 12/08/09, by reporting week (Table 4) and age group (Table 5)
4 Week Laboratory N umber 5 Age group Laboratory
notified confirmed cases Hospitalised confirmed cases
22 1 0 <1 2
23 1 0 1-4 7
24 1 0 5-14 12
25 2 0 15-24 42
26 19 1 25-34 13
27 34 0 35-44 7
28 6 5 45-64 14
29 13 9 65-74 3
30 8 8 75+ 0
31 6 2 Total 100
32 8 7
33 1 1
Total 100 33
As at 12/08/2009 there have been 100 laboratory confirmed cases reported to NPHS Wales.
Thirty-three of these cases were hospitalised, 31 of whom have now been discharged. The age
group currently with the highest numbers of confirmed cases is 15 - 24 years. Confirmed cases
have been reported in 20 LHB areas in Wales. These figures represent only laboratory confirmed
cases which are reported directly to NPHS Wales. Actual numbers of cases are likely to be higher
and during the treatment phase of the pandemic most cases will not be reported directly to NPHS
Wales or virologically confirmed. The laboratory confirmed hospitalised patients in tables 3 - 5 are
a subset of the total number of patients who have been admitted to hospital with influenza like
symptoms.
-4-
Latest data from the Welsh Assembly Government’s Service Delivery and Performance
Management Directorate indicate that as at 12/09/08 there were Eight patients across Wales
hospitalized in connection with swine influenza, three of whom suffer from identified co-
morbidities or underlying conditions, with two patients in critical care (although swine influenza
A(H1N1)v has not been confirmed in either of these cases).
Rapid surveillance of influenza using Audit+
Figure 3. Rapid surveillance of influenza in Wales using Audit+, clinical consultation
rate, rolling 7 day rate as at 12/08/09.
400
350
Consultation rate per 100,000
300
250
200
150
100
50
0
01/05/2009
05/05/2009
09/05/2009
13/05/2009
17/05/2009
21/05/2009
25/05/2009
29/05/2009
02/06/2009
06/06/2009
10/06/2009
14/06/2009
18/06/2009
22/06/2009
26/06/2009
30/06/2009
04/07/2009
08/07/2009
12/07/2009
16/07/2009
20/07/2009
24/07/2009
28/07/2009
01/08/2009
05/08/2009
09/08/2009
13/08/2009
17/08/2009
21/08/2009
25/08/2009
29/08/2009
Figure 4. Rapid surveillance of influenza in Wales LHB influenza consultation rates
(per 100,000 practice population), rolling 7 day rate as at 12/08/09.
Surveillance for influenza consultations in Wales using Audit+, shows the rolling seven day
consultation rate for influenza has decreased over the last week (see figure 3), with most LHB
areas showing similar trends. As at 12/08/09 the consultation rate for Wales as a whole was 55.3
per 100,000 (compared to 89.02 per 100,000 reported seven days ago). Consultation rates in all
LHB areas exceed 25 per 100,000 (see figure 4), no LHB area has a consultation rate exceeding
100 per 100,000 (compared to five LHB areas in the preceding week). Consultation rates appear
-5-
highest in South East Wales. Rolling 7 day age specific consultation rates have decreased in all
age groups over the last seven days, but are highest in children aged four years and under (figure
5).
Figure 5. Rapid surveillance of influenza in Wales LHB influenza age group specific
consultation rates (per 100,000 practice population), rolling 7 day rate as at 12/08/09.
400
350
Consultation rate per 100,000
300
250
200
150
100
50
0
<01 1-4 5-14 15-44 45-64 65-75 75+
Age group
1
Figure 6. Influenza related calls to NHS direct Wales (as a percentage of total calls)
to week 32 2009 (as of 12/08/09).
60.0
50.0
Percentage
40.0
30.0
20.0
10.0
0.0
17-Jul-06
06-Nov-06
23-Apr-07
18-Jun-07
13-Aug-07
08-Oct-07
14-Jul-08
03-Nov-08
20-Apr-09
15-Jun-09
06-Dec-05
31-Jan-06
27-Mar-06
22-May-06
11-Sep-06
01-Jan-07
26-Feb-07
03-Dec-07
28-Jan-08
24-Mar-08
19-May-08
08-Sep-08
29-Dec-08
23-Feb-09
Week commencing
During week 32, the percentage of total calls to NHS Direct Wales which were influenza related
decreased to 29.8% (figure 6).
1
Data supplied by Health Statistics and Analysis Unit, Welsh Assembly Government.
Flu related calls are the sum of calls recorded as 'cold/flu', 'cough', 'headache', 'fever' and 'sore throat'.
-6-
Links:
NPHS Wales Swine influenza webpage:
http://www.wales.nhs.uk/sites3/page.cfm?orgid=457&pid=37250
HPA Swine influenza webpage:
http://www.hpa.org.uk/webw/HPAweb&HPAwebStandard/HPAweb_C/1240732818210?p=12
31252394302
NICE influenza antiviral usage guidance:
http://www.nice.org.uk/Guidance/TA158
Wales influenza information:
http://www.wales.nhs.uk/sites3/page.cfm?orgid=457&pid=27922
England influenza information:
http://www.hpa.org.uk/infections/topics_az/influenza/seasonal/default.htm
Scotland influenza information:
http://www.hps.scot.nhs.uk/search/atozdetail.aspx?subject=95
Northern Ireland influenza information:
http://www.cdscni.org.uk/publications/default.asp
European Centre for Communicable Disease:
http://ecdc.europa.eu/
European influenza information:
http://www.euroflu.org/
Avian influenza in the UK:
http://www.hpa.org.uk/infections/topics_az/influenza/avian/default.htm
Avian influenza/ pandemic information:
http://www.who.int/csr/disease/avian_influenza/en/index.html
-7-
