Weekly pandemic flu media update

26 November 2009

KEY POINTS

• The consultation rate for flu-like illness in England from the Royal College of General Practitioners (RCGP) scheme has increased slightly to 39.2 per 100,000 in week 47 compared to 35.9 in week 46. This remains above the English baseline threshold of 30/100,000.
• The estimated cases self referring to the National Pandemic Flu Service have shown a slight increase. These are primarily the result of increases in collection rates in the 1-4 and 5-14 year old age groups.
• 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 46,000 new cases in England last week (range 23,000 to 99,000) which represents a decrease from the previous week.    
  This estimate incorporates data from National Pandemic Flu Service and GP consultations.
• The HPA estimates a cumulative total number of cases of 760,000 (with a range 360,000 to 1,580,000) since the pandemic began.
  

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 47 (ending 22 November) GP consultation rates for flu-like illness in England have shown a slight increase compared to the previous week (35.9 per 100,000 in week 46 to 39.2 per 100,000 in week 47) which is still above the English baseline threshold of 30/100,000.

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 of 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 showed a slight increase from 48.4 per 100,000 in week 46 to 50.5 per 100,000 in week 47. The weekly rate for flu-like illness in all SHA regions and all age groups showed a mixed picture with some increasing and others decreasing. Larger increases are in the South Central and South West SHAs.

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® - weekly consultation rate for influenza-like illness by English SHA (all ages)

Figure 4: QSurveillance influenza-like illness rate by age band in week 47 (ending 22 November)

The latest weekly flu-like illness rates show that the highest flu-like illness consultation rates were in the 1-4 year-old age group. Compared with week 46 this week (week 47) rates have increased in all age bands except the 15-24 and 65+ year age bands where the rates have decreased. The largest increase are in the <1 (25%)="(25%)" and="and" 1-4="1-4" (30%)="(30%)" year="year" age="age" bands.</p="bands.</p" />

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

To date (as of 25 November 2009) 3,695 viruses have been analysed by the HPA Centre for Infections for the genetic marker commonly associated with resistance to oseltamivir in seasonal H1N1 flu (H274Y). 22 viruses have been found to carry this marker in the UK with three of these, through additional testing, showing evidence of resistance when viral growth is tested in the presence of oseltamivir whilst retaining sensitivity to zanamivir. In addition, 293 specimens have been fully tested for susceptibility. 

Information on medical history was available for 17 cases, all of whom had an underlying medical condition: 14 were immunosuppressed and three had chronic respiratory or neurological illnesses.

Testing of samples, taken before and after treatment with oseltamivir, show that the antiviral resistance in 14 of the cases was treatment-induced, four are probably acquired through person to person transmission, and in four cases the origin of the resistant virus is still under investigation.

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.

There have been no significant changes in the virus.

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: 783 patients (currently hospitalised as of 8am on 25 November). 

Deaths - the number of deaths related to swine flu in England is 163 (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 25 November 2009)
Total deaths reported: 7,909

In the last 7 days, the total number of deaths reported globally has increased by 10% on the previous week.

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 20 November that for:

• Tropical regions: the intensity of influenza transmission is variable in tropical regions of the Americas and Asia. Most countries of the tropical regions of Central and South America continue to report declining influenza activity, with the exception of Peru and Colombia. In the Caribbean Epidemiology Centre (CAREC) countries, after a recent peak of disease activity, rates of ARI (Acute Respiratory Illness)  have declined over the past 3-4 weeks. With the exception of Sri Lanka, overall transmission continues to decline in most parts of tropical South and South East Asia. In Hong Kong SAR, rates of ILI (Influenza-like illness) have returned to baseline after a recent wave of predominantly pandemic H1N1 influenza in September and October.
• Central and Western Asia: increasing disease activity and pandemic influenza virus isolation continues to be reported in several countries. A high intensity of respiratory diseases with an increasing trend was reported in Kazakhstan. Recent increases in rates of ILI or ARI have been observed in Uzbekistan and in parts of Afghanistan (particularly in the capital region and in southern and north-eastern provinces). In Israel, sharp increases in rates of ILI and pandemic virus detections have been reported in recent weeks.
• Temperate northern hemisphere regions: The situation remains similar since the last update. The early arriving winter influenza season continues to intensify across parts of North America and much of Europe. However, there are early signs of a peak in disease activity in some areas of the northern hemisphere.
  • In Europe: In Europe, widespread and increasing transmission of pandemic influenza virus was observed across much of the continent but the most intense circulation of virus occurred in northern, eastern, and south-eastern Europe. Transmission appears to have peaked in a few countries of Western Europe including Iceland, Ireland, and Belgium after a period of sustained intense transmission. Further east, sharp increases in the rates of ILI were reported in Serbia, Moldova, Norway, Lithuania, and Georgia, and in ARI in Belarus, Bulgaria, Romania, and Ukraine. A moderate or greater impact on the healthcare system was reported in parts of northern and south-eastern Europe. Greater than 20% of all sentinel respiratory specimens tested positive for influenza in at least 20 countries, with ? 50% of samples testing positive for influenza in Spain, Portugal, Estonia, Slovenia, Slovakia, Moldova, Bosnia and Herzegovina, Greece, Norway, Finland, Denmark, Belgium, Iceland, and Ireland. Over 99% of subtyped influenza A viruses in the European region were pandemic H1N1 2009.
  • In the United States: influenza transmission remains active and geographically widespread, although disease activity appears to have recently peaked in most areas except in the north eastern states. In Canada, influenza transmission continues to intensify without a clear peak in activity; the ILI consultation rate, which has been highest among children aged 5-19, continues to significantly exceed mean rates observed over the past 12 influenza seasons.
• Temperate southern hemisphere region: very little pandemic activity reported.
• East Asia: influenza transmission remains active. Intense influenza activity continues to be observed in Mongolia with a severe impact on the healthcare system; however, disease activity may have recently peaked in the past 1-2 weeks. In Japan, influenza activity remains elevated but stable nationally, and may be decreasing slightly in populated urban areas. A small number of seasonal H3N2 and H1N1 influenza viruses continue to be detected in China and South East Asia, though the proportion of seasonal viruses is declining in relation to the proportion of pandemic influenza H1N1.

More information on the latest global situation can be found on the WHO website at: http://www.who.int/csr/don/2009_11_20a/en/index.html

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: 3 June 2010