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Home News centre National Press Releases 2009 Press Releases ›  Weekly pandemic flu media update

Weekly pandemic flu media update

17 September 2009

KEY POINTS

  • The rates of flu-like illness and related activity have started to increase in England. The increase was mainly seen in school age children.
  • Hospitalisations of people with suspected pandemic flu in England have levelled overall. The majority of cases continue to be mild.
  • Two samples from UK patients have been shown to have the genetic change associated with oseltamivir resistance. Both were from immunocompromised patients. One has been shown to be resistant, the other is undergoing further tests to confirm resistance. Globally over 10,000 specimens have been tested and 23 have been shown to be resistant to oseltamivir.
  • Interpretation of data to produce estimates on the number of new cases continues to be subject to a considerable amount of uncertainty. HPA modelling gives an estimate of 5,000 new cases in England last week (range 3,000 to 11,000). 
    This estimate incorporates data from National Pandemic Flu Service and GP consultations.

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:
www.hpa.org.uk/swineflu/surveillance&epidemiology

CLINICAL INDICATORS
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

Figure 1: Current estimated weekly RCGP consultation rates of flu-like illness

QSurveillance®
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 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 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)

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.

SYNDROMIC SURVEILLANCE

NHS Direct
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.

VIRAL CHARACTERISTICS
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.

SEVERITY
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).

INTERNATIONAL SUMMARY

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:

  • Tropical regions: increasing levels of respiratory disease continue to be reported from tropical regions of Asia (India, Bangladesh, and Cambodia) and South America (Bolivia, Ecuador, and Venezuela), though many countries in Central America and the Caribbean have reported declining activity for the second week in a row.
  • Temperate southern hemisphere regions: (represented by countries such as Chile, Argentina, Australia, New Zealand, and South Africa); flu activity continues to decrease or return to baseline.
  • Temperate northern hemisphere regions: activity is variable. In the United States, regional increases in flu activity are being reported (particularly in the south eastern states). Most of Europe is reporting low or moderate respiratory disease activity, but parts of Eastern Europe are beginning to report increases in activity.

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/
ENDS
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:

  • Maintaining good basic hygiene, for example washing hands frequently with soap and water to reduce the spread of virus from your hands to face or to other people.
  • Cleaning hard surfaces (e.g. door handles) frequently using a normal cleaning product.
  • Covering your nose and mouth when coughing or sneezing, using a tissue when possible.
  • Disposing of dirty tissues promptly and carefully.
  • Making sure your children follow this advice. 

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