9 July 2009
Following the move from laboratory testing for confirmation of swine flu (H1N1v) to clinical diagnosis of cases, the level of flu in the community is being monitored using a range of surveillance mechanisms. These enable HPA to accurately estimate flu levels, monitor new and emerging viruses and identify trends in activity. Our experience over many flu seasons means we can confidently continue to monitor the incidence and distribution of this pandemic virus over the summer and beyond.
Figures 1 & 2 below are sample graphical representations to show how primary care surveillance of flu-like illness proves a good comparator to laboratory confirmations (daily reporting of laboratory confirmed cases alongside weekly and daily primary care surveillance reports for flu-like illness).
Figure 1: Comparison of daily laboratory confirmed H1N1v case reports and weekly RCGP reports of flu-like illness, UK
Figure 2: Comparison of daily laboratory confirmed H1N1v case reports and daily QSurveillance® reports of influenza-like illness, UK
Clinical data are obtained from GP surgeries that report the weekly and daily consultations for flu-like illness and other acute respiratory illness.
Current estimated weekly Royal College of General Practitioners (RCGP) consultation rates of flu-like illness
From a network of approximately 100 general practices located throughout England covering a population of approximately 900,000 with an equal distribution within each of three defined reporting regions; North, Central and South.
In week 27 (ending 5 July), GP consultation rates for flu-like illness have increased markedly in England. This rate (51.9 per 100,000) is now above the threshold level for normal seasonal flu activity (30 per 100,000); rates in the South of England were particularly high (77.6), and Northern England low (6.8).
Figure 3: Current estimated weekly RCGP consultation rates of flu-like illness
Set up by the University of Nottingham and EMIS (the main supplier of general practice computer systems within the UK) in collaboration with the Health Protection Agency. QSurveillance® is a not-for-profit network over 3,300 general practices covering a total population of almost 22 million patients (> 25% of the UK population).
For QSurveillance® the flu-like illness daily consultation rate was 9.8 per 100,000 on Tues 7th July (this remains the highest Tuesday rate recorded since the start of the outbreak, equivalent to estimated rates expected when 'normal seasonal flu' is circulating).
NB: QSurveillance® is based on data from 43% of England's population (about 3000 practices), 10% of the population in Wales, 17% in Northern Ireland, and 0% in Scotland.
Figure 4: QSurveillance® - daily consultation rate for flu-like illness in UK (all ages) with 7-day moving average for 2008 and 2009
Figure 5: QSurveillance® flu-like illness weekly rate for week 27 (week ending 5 July) by age band
NHS Direct has an existing algorithm for cold/flu calls. There is a significantly higher proportion of 'cold/flu' calls to NHS Direct across most of England and Wales compared with seasonal data from previous winters, especially for West Midlands and London SHAs.
Figure 6: Daily NHS Direct/HPA Syndromic Surveillance System estimated total 'cold/flu' calls by SHA.(comparative data provided*)
* Based on between 8,000 and 18,000 calls each day to NHS Direct in April, May and June 2009. In recent winter flu seasons, the maximum proportion of calls to NHS Direct for 'cold/flu' has been 2.8%.
Antiviral susceptibility (as at 03/07/09): 17 of the swine flu (H1N1v) isolates have been fully tested for susceptibility by the Health Protection Agency. All 17 were found to be sensitive to oseltamivir and zanamivir and resistant to amantadine. One hundred and ninety-nine positive specimens have been analysed for the marker commonly associated with resistance to oseltamivir in seasonal influenza (H274Y), all were found not to carry this marker.
Disease severity continues to be monitored. The disease is generally mild in most people so far, but is proving severe in a small minority of cases.
Swine flu hospitalisations in England: 335 patients
12 deaths have been reported in England.
(Health warning: this figure represents cases that have been confirmed with swine flu through laboratory testing. It does not represent the number of deaths that can be attributed to swine flu)
Notes to editors
General infection control practices and good respiratory hand hygiene can help to reduce transmission of all viruses, including swine flu. This includes:
Further information on swine flu is available on the Health Protection Agency's website at www.hpa.org.uk/swineflu.
For media enquiries only please contact the Health Protection Agency's Centre for Infections press office on
020 8327 7080
020 8327 6647
020 8327 7098
020 8327 7097
020 8327 6690
Last reviewed: 10 July 2009