HPS National Influenza Report
Summary of surveillance of influenza and
other seasonal respiratory illnesses
Week ending 28 April 2013 – week 17
1 Summary
• This report provides an update on influenza and other seasonal respiratory pathogen activity for
the week ending 28 April 2013. For the remainder of the season we will publish bulletin style weekly
updates unless there are significant changes in influenza activity which would require more detailed
reporting.
• This report contains summary epidemiological information on influenza-like illness (ILI), its severity
and impact in the community and secondary care settings, and estimates of vaccine uptake.
• The GP consultation rate for influenza-like illness (ILI) has been calculated using the same method as
in the season 2011/12. Please refer to the technical document for further information.
• Clinical influenza activity decreased compared to the previous week and was below the threshold for
normal seasonal activity overall. Virological influenza activity detected through the GP sentinel scheme
and through non-sentinel sources decreased compared to the previous week. Please note that the
data for week 17 is provisional.
• One influenza case with severe infection requiring management in an intensive care unit (ICU) was
reported to HPS in the last week. Since week 40 2012, a total of 124 influenza infections requiring ICU
have been reported to HPS (60 A(H3), 20 A(H1N1)pdm09, 7 A (subtype unknown), 37 B), 35 of who
were known to have died.
• Levels of non-influenza seasonal respiratory pathogens overall were in line with expected levels, with
the exception of the levels of Human Metapneumovirus and parainfluenza infections, which were
slightly higher than at the same time last year.
• Whilst community circulation of influenza appears to be decreasing, antivirals can still be used in
primary care where clinically appropriate. The CMO letter on antiviral prescribing was issued on 20
December 2012 and can be accessed at: http://www.sehd.scot.nhs.uk/cmo/CMO(2012)10.pdf.
2 Community Surveillance – GP consultation rates and NHS 24 calls
• GP consultation rates for ILI are estimated
based on weekly data submissions by 99% of
all Scottish GP practices.
• The proportion of cold/flu calls to NHS 24
increased slightly this week but remained low
and within expected levels at this time of year.
Figure 1: GP consultation rates for ILI in Scotland; weekly
rates per 100,000 population, week 40 2012 to week 17 2013,
compared to seasons 2010/11 and 2011/12
300
ILI rate per 100,000 population
• In week 17, the GP consultation rate for ILI
decreased compared to last week (11.4 per
100,000 population), and was within expected
levels for this time of year, and below the
threshold for normal seasonal activity.
2010/11 weekly rate
250
2011/12 weekly rate
2012/13 weekly rate
threshold for normal
seasonal activity
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
• Since week 40 2012, a total of 124 influenza
infections requiring ICU have been reported
to HPS (60 A(H3), 20 A(H1N1)pdm09, 7 A
(subtype unknown), 37 B).
• Influenza A or B has been identified in 70%
and 30% of cases, respectively to date.
• Of the 124 cases, 15 were under 15 years of
age, 64 were in the age group 15-64 and 45
were 65 years or older. Twenty-eight cases
were reported by Health Boards in the North
of Scotland, 54 from the West of Scotland
and 42 from the East of Scotland1. Thirty-five
individuals were known to have died.
Figure 2: Number of influenza cases with severe infection
requiring intensive care management by week of hospital
admission, week 40 2012 to week 17 2013
18
16
14
Number of cases
• One influenza case with severe infection
requiring management in an intensive care
unit (ICU) was reported to HPS in the last
week (one B) (Figure 2).
12
10
8
6
4
2
0
40
42 44 46
48 50
52
2
4
Week
Influenza A - reported to week 16
Influenza B - reported to week 16
6
8
10 12
14 16 18
20
Influenza A - reported in week 17
Influenza B - reported in week 17
4 Virological Surveillance (sentinel and non-sentinel)
• In week 17, 18 influenza infections (five A (subtype unknown), two A(H1N1)pdm09, 11 B) were
reported through non-sentinel sources (ECOSS). The ECOSS swab positivity2 for any type of influenza
(3.8%) decreased compared to the previous week (8.4%). No influenza infections were reported
through the GP sentinel scheme (0/19), compared to a swab positivity of 11.1% (4/36) in the previous
week. Please note that the data for week 17 is provisional.
• In general, the levels of non-influenza seasonal pathogens reported through the GP sentinel scheme
and ECOSS were in line with expected seasonal levels.
• Levels of parainfluenza and Human Metapneumovirus reported through ECOSS were raised and
slightly above levels seen at the same time last year.
• Whilst community circulation of influenza appears to be decreasing, antivirals can still be used in
primary care where clinically appropriate. The CMO letter on antiviral prescribing was issued on 20
December 2012 and can be accessed at: http://www.sehd.scot.nhs.uk/cmo/CMO(2012)10.pdf.
• Since 20 December 2012, a small increase in antiviral prescriptions has been recorded through
ePharmacy, the majority of prescriptions appear to be associated with closed setting influenza
outbreaks.
• Antiviral guidance is available at: http://www.hps.scot.nhs.uk/resp/publicationsdetail.aspx?id=53562
1 North: Western Isles, Shetland, Orkney, Highland, Grampian, Tayside; East: Fife, Lothian, Borders, Forth Valley; West: Greater Glasgow & Clyde,
Lanarkshire, Ayrshire & Arran, Dumfries & Galloway
2 Percentage positive is derived from data from the Glasgow, Edinburgh and Aberdeen laboratories, for which denominator data is available.
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HPS National Influenza Report (Week ending 28 April 2013 – week 17)
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5 Outbreaks
• No closed setting outbreaks of acute respiratory infections were reported to HPS in the last week.
6 Vaccine uptake
• Data on estimated vaccine uptake are compiled to the end of March each season. The data provided
for week 13 (76.5% in those aged 65 years and above; 55.9% in the at-risk groups) is the last update
for the estimated vaccine uptake for this 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 2012/2013.
7 Mortality
• Information on mortality from all causes is available from the General Registrar’s Office for Scotland
(now part of National Records of Scotland). Excess deaths relating to all causes of death during the
winter months are often attributed in part to influenza.
• The number of deaths by age group was within the expected levels for the past four weeks, with the
exception of a small excess detected in the age group 65 years and older in week 15. The cumulative
excess mortality for Scotland since week 40 is estimated to be 730. This should be interpreted with
caution as data, especially for the last two weeks, are still provisional.
• Please note, that the number of influenza cases with severe infection requiring ICU management,
(including deaths) are reported in section 3.
8 International Situation
• During week 16, GP consultation rates for influenza-like illness remained low in all schemes across
the rest of the UK. Datamart swab positivity decreased compared to the previous week: 8.5% (65/761);
the RCGP sentinel swab posivity increased slightly to 26.3% (5/19).
• In week 16, 22 new admissions of confirmed influenza cases to ICU/HDU (13 A (subtype unknown),
six A(H3N2), two A(H1N1)pdm09) and one B and one confirmed influenza death in ICU/HDU were
reported through the national USISS mandatory ICU scheme across the UK . For the most up to date
information on ICU/HDU cases in the UK please see the HPA report.
• Nine new acute respiratory outbreaks were reported in week 16 across the UK (seven in care homes
and two in hospitals). Six had a virological result available (five Influenza A (subtype unknown) and
one B).
• In week 16, influenza activity continued to decline or had already returned to baseline levels in all
reporting countries across Europe. After more than three months of active transmission, the 2012–13
influenza season appears to be coming to an end. Twenty-four countries reported low-intensity
transmission while three countries (Latvia, the Netherlands and Sweden) still reported medium
intensity. Decreasing or stable trends were reported by almost all reporting countries.
• Across Europe, the proportion of influenza-positive sentinel specimens (week 16: 26%) continued
to decrease since the peak observed in week 5 2013 (61%). Since week 40 2012, 47% of sentinel
surveillance specimens testing positive for influenza virus have been type A and 53% type B. Of the
Influenza A viruses subtyped, the proportion of A(H1)pdm09 viruses was 62%.
2 May 2013
HPS National Influenza Report (Week ending 28 April 2013 – week 17)
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• Influenza activity across the northern temperate regions have continued to decline to near interseasonal levels in much of North America and northern Asia though low level persistent transmission
was still noted in many countries. The persistence of transmission in the northern hemisphere
temperate regions has been associated with increasing numbers of Influenza B virus appearing late in
the season in a number of countries of North America. Prior to this, Influenza A(H3N2) was the most
commonly detected virus in North America, and both A(H1N1)pdm09 and A(H3N2) were detected in
varying proportions in different countries of northern Asia.
• Low levels of influenza activity continued to be reported across the tropical regions of the world and
activity in countries of the southern hemisphere remained at inter-seasonal levels.
• To 29 April 2013, 121 cases of human infection with Influenza A(H7N9) in China have been reported
by ECDC. Twenty-three of the cases have died. There is currently no evidence of on-going human-tohuman transmission of the Influenza A(H7N9) virus. Based on current evidence the risk of disease
spread to Europe has been assessed as low, although individual cases coming from China cannot
be ruled out. Further information on investigation and management of possible cases in returning
travellers is available on the HPS website http://www.hps.scot.nhs.uk/resp/publicationsdetail.
aspx?id=54528. For the most up to date information on A(H7N9) cases and assessment of the risk to
Europe, please see the ECDC website: http://www.ecdc.europa.eu/en/press/news/Pages/News.aspx
© Health Protection Scotland 2013
Report produced by: HPS Flu Team
2 May 2013
Email: [email protected]
HPS National Influenza Report (Week ending 28 April 2013 – week 17)
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