17 September 2009
Following the move from laboratory testing for confirmation of swine flu to clinical diagnosis of cases, the level of flu in the community is being monitored using a range of surveillance mechanisms, including the RCGP consultation rates, QSurveillance®, and the National Pandemic Flu Service.
A more detailed UK weekly epidemiology update can be accessed at:
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 covering a population of approximately 900,000 with an equal distribution within each of three defined reporting regions; North, Central and South.
In week 37 (ending 13 September) GP consultation rates for flu-like illness in England increased compared to the previous week (8.6 per 100,000 to 12.9 per 100,000). The increase was mainly seen in school age children.
Figure 1: 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).
The weekly QSurveillance® flu-like illness consultation rate increased from 10.9 per 100,000 in week 36 to 14.5 per 100,000 in week 37. The daily rate for flu-like illness for the last few days remained low and at similar levels for all regions.
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 2: QSurveillance® - weekly consultation rate for flu-like illness in England, Wales and Northern Ireland (all ages)
Figure 3: QSurveillance® - daily consultation rate for influenza-like illness by English SHA (all ages)
Figure 4: QSurveillance influenza-like illness rate by age band in week 37 (ending 13 September)
The latest weekly flu-like illness rates show that the highest consultation rates were in the 15-24 year age group followed by the 25-44 year age group. Compared to week 36 there has been an increase in all age groups.
On 23 July the National Pandemic Flu Service was implemented. This had an impact on the number of 'cold/flu' calls received through the routine NHS Direct service. For this reason, data from NHS Direct do not reflect the true pattern of cold/ flu callers and so are not currently an accurate surveillance tool.
The Health Protection Agency has reported to the World Health Organization (WHO) the identification in the UK of a pandemic H1N1 2009 flu virus resistant to the antiviral oseltamivir (Tamilflu®).
The resistant virus was identified in an immuno-compromised patient. The virus has a genetic change, H274Y in the N1 gene and is resistant to oseltamivir but retains susceptibility to the antiviral zanamivir (Relenza®).
Preliminary test results have also shown that a second virus (in a separate immuno-compromised patient) has the genetic change. We will be able to confirm if this virus is resistant at the end of the week.
There is no evidence of onward transmission of the resistant viruses.
This is not an unexpected development. If the second sample is confirmed, then these two samples are among a small number of resistant pandemic H1N1 2009 flu viruses to have already been identified worldwide through enhanced surveillance during the current pandemic. To date the manufacturers of oseltamivir (Roche) have reported 23 cases globally. Based on current information, these isolates appear to be sporadic and at this time there is no evidence of widespread antiviral resistance among pandemic H1N1 2009 flu viruses.
Testing carried out by the HPA indicates that both patients were initially infected with oseltamivir-susceptible virus, with resistance to the drug developing during their treatment. The emergence of antiviral drug resistant flu viruses during treatment has been reported in the past and its link to immuno-compromised patients is well established.
In a healthy individual the body's immune system would ordinarily effectively eliminate any virus. However, with immuno-compromised individuals, their immune response is affected and they continue to shed flu virus for prolonged periods.
The one, possibly two, UK cases were identified through testing carried out on flu virus samples received at the Agency's Centre for Infections. We are confident that these surveillance measures will enable us to identify any further resistant isolates.
To date (as of 16 September 2009) 913 viruses have been analysed by the Centre for Infections for the genetic marker commonly associated with resistance to oseltamivir in seasonal H1N1 flu (H274Y). These are the only two viruses found to carry this marker in the UK. In addition, 253 specimens have been fully tested for susceptibility; all, apart from one, were found to be sensitive to both oseltamivir and zanamivir.
The Agency is continually assessing its advice to government on health protection policies such as antiviral use. Currently there is no requirement to change existing guidance.
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: 143 patients (currently hospitalised as of 8am on 16 September).
Deaths - the number of deaths related to swine flu in England is 67 (This figure represents the number of deaths in individuals with swine flu but does not represent the number of deaths that can be attributed to swine flu).
Confirmed global deaths reported by ECDC (Update 17:00 CEST 15 September 2009)
Total deaths reported: 3,696
In the last 7 days, the total number of deaths reported globally has increased by 6% - a much slower increase compared to recent weeks.
NB: Laboratory confirmed case numbers are no longer being reported for most countries as they do not give a representative view of the actual number of cases worldwide.
The World Health Organization (WHO) reported on 11 September that for:
This update summarises information published by WHO about the latest global situation and is also published on the HPA website at http://www.hpa.org.uk/HPA/Topics/InfectiousDiseases/InfectionsAZ/1251473469008/
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 7097
020 8327 7098
020 8327 6690
020 8327 6647
Last reviewed: 27 May 2010