HPS Weekly National Influenza Report
Summary of surveillance of influenza and other
seasonal respiratory illnesses
Week ending 1 April 2012 – week 13
1Summary
• This report provides an update on influenza and other seasonal respiratory pathogen activity for the
week ending 1 April 2012. For this season, we will provide detailed influenza update reports on a
monthly basis with bulletin style weekly updates in the weeks in between.
• This report contains summary epidemiological information on influenza-like illness (ILI), its severity
and impact in the community and secondary care settings, and information on vaccine uptake
estimates.
• The GP consultation rate for influenza-like illness (ILI) has been calculated using a different method
this season. Please refer to the technical document for further information on this.
• Clinical influenza activity is low overall in Scotland and virological influenza activity was stable
compared to the previous week. Levels of non-influenza seasonal viral pathogens are in line with
expected levels. RSV activity is lower than at the same time last year. The number of Mycoplasma
pneumoniae reports peaked towards the end of 2011, and has now decreased to levels comparable to
the same time in previous years.
2 Community Surveillance – GP consultation rates and NHS24 calls
• The proportion of cold/flu calls to NHS24
increased slightly this week but remained low
overall and below expected levels at this time
of year.
Figure 1: GP consultation rates for ILI in Scotland; weekly rates per
100,000 population, week 40 2011 to week 13 2012
300
2010/11 weekly rate
Rate per 100,000 population
• In week 13, the GP consultation rate for ILI
was low (11.6 per 100,000 population). This
is a slight decrease on last week and within
expected levels for this time of year, below the
threshold for normal seasonal activity.
2011/12 weekly rate
250
200
150
100
50
0
40
42
44
46
48
50
52
2
4
Week
6
8
10
12
14
16
18
20
3 Severe Illness Surveillance
• There was one laboratory confirmed case with severe infection requiring intensive care management
due to an Influenza A/H3 infection reported to HPS last week.
• A total of fourteen influenza infections requiring intensive care management have been reported to
HPS since week 40 2011 (10 Influenza A/H3, 3 Influenza A (subtype unknown), 1 Influenza B).
• Of these 14 cases, the majority of cases were over 45 years of age and had risk factors reported. Two
individuals are known to have died. 4 Virological Surveillance (sentinel and non-sentinel)
• In week 13, a total of 38 influenza infections (8 A/H3, 30 A (subtype unknown)) were reported through
non-sentinel sources (ECOSS).The percentage positive for any influenza for non-sentinel samples was
4.4%.1 Three Influenza A/H3 infections were reported through the GP sentinel scheme (percentage
positive: 3/27, 11.1%). Please note that the data for week 13 is provisional.
• In general, the levels of non-influenza viral pathogens reported through the GP sentinel system and
ECOSS were in line with expected seasonal levels.
• The number of adenovirus infections reported through ECOSS has decreased since week 11 and was
within levels seen at the same time last year.
• The level of RSV and rhinovirus reports in ECOSS was lower than at the same time last year.
• The number of Mycoplasma pneumoniae reports was stable over recent weeks and within levels seen
at the same time last year.
• Levels of Human metapneumovirus and parainfluenza reports were within levels seen at this time last
year.
5Outbreaks
• There were two confirmed closed setting Influenza A/H3 outbreaks in a nursing home and a hospital,
reported to HPS in the last week.
6 Vaccine uptake
• Estimated uptake in pregnant women without
additional risk factors was lower than at this
time last year; 39.6% (2012) vs 64.9% (2011).
Uptake in pregnant women with additional risk
factors was also lower than this time last year;
59.9% (2012) vs 74.8% (2011).
Figure 2: Estimated seasonal influenza vaccine uptake
in Scotland by risk group, week 40 to week 13 for season
2010/2011 and season 2011/2012 respectively
100
90
80
Vaccine uptake (%)
• To week 13, provisional data showed that
estimated vaccine uptake overall for Scotland
was higher than at the same time last year;
76.2% (2012) vs 75.4% (2011) for those aged
65 years and above; 56.4% (2012) vs 56.1%
(2011) for those under 65 years old in an atrisk group.
65 and over, 2011-12
65 and over, 2010-11
All risk groups, 2011-12
All risk groups, 2010-11
Pregnant/no risk 2011-12
Pregnant/no risk 2010-11
Pregnant/at risk 2011-12
Pregnant/at risk 2010-11
70
60
50
40
30
20
10
0
40 41 42 43 44 45 46 47 48 49 50 51 52 1
• Figure 2 shows the estimated cumulative
vaccine uptake in Scotland by calendar week
for the season 2011/2012, compared to the previous season.
2 3 4 5
6 7
8 9 10 11 12 13
Week
• This is the final estimated seasonal influenza vaccine uptake for the 2011/2012 season. In the early
summer, HPS will provide information from NSS Practitioner Services Division on the final validated
vaccine uptake or usage. Such data is collated on the basis of claims for payment by General
Practitioners to the end of the financial year 2011/2012.
7 International Situation
• During week 12, clinical indicators of influenza activity in the UK remained relatively low and virological
indicators of influenza activity declined slightly compared to the previous week [Datamart swab
positivity: 12.9% (79/612), RCGP/RMN sentinel swab positivity 35.1% (13/37)].
1 Percentage positive is derived from data from the Glasgow, Edinburgh and Aberdeen laboratories, for which denominator data is available.
5 April 2012
HPS Weekly National Influenza Report (Week ending 1 April 2012 – week 13)
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• From week 40 to week 12, a total of 213 ICU/HDU severe acute respiratory illness cases were
reported across the UK, with 22 (10.3%) resulting from Influenza A/H1N1 pdm09, 63 (29.6%) from
Influenza A/H3N2, 116 from A (subtype unknown) and 12 (5.6%) from Influenza B. Twenty ICU/HDU
influenza deaths across the UK have been reported (five A (unknown subtype), twelve A/H3N2 and
three B). For the most up to date information on ICU/HDU cases in the UK please see the HPA report.
• Across Europe, decreasing trends in influenza activity were reported by 21 countries in week 12
(fourteen of which have reported such trends for at least two consecutive weeks). Only 3 countries
(Lithuania, Poland, Slovakia) reported increasing trends. The decrease in the proportion of influenzapositive sentinel specimens together with the growing number of countries reporting continuously
decreasing trends in the incidence of ILI or ARI indicated that the epidemic peak has passed in most
European countries.
• Overall, influenza activity in the northern hemisphere was reported to be decreasing. In North America
this influenza season was later than most other seasons, and whilst activity in some areas appeared to
be peaking, increasing activity was still reported from some areas. Most countries in North Africa and
the Middle East were reporting influenza activity at or near inter-seasonal levels. Influenza activity in
northern China decreased slightly. • Most countries in the tropical zone reported low levels of influenza activity.
• The most commonly detected virus type and subtype throughout most of the northern hemisphere
temperate zone has been Influenza A/H3N2 to date, although the proportion of Influenza B has
increased. In the later part of the season, increasing genetic and antigenic diversity in A/H3N2 viruses
has been noted. In Mexico, Influenza A/H1N1 pdm09 was still the predominant virus circulating. China
and surrounding countries were still reporting a predominance of Influenza B.
© Health Protection Scotland 2012
Report produced by: HPS Flu Team
5 April 2012
Email: [email protected]
HPS Weekly National Influenza Report (Week ending 1 April 2012 – week 13)
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