Weekly pandemic flu media update

19 November 2009

KEY POINTS

• The consultation rate for flu-like illness in England from the Royal College of General Practitioners (RCGP) scheme has decreased slightly to 35.9 per 100,000 in week 46 compared to 37.8 in week 45. This is still above the English baseline threshold of 30/100,000.
• The estimated cases self referring to the National Pandemic Flu Service have shown an overall decline. Antiviral collection numbers are variable across England with increases in some regions and decreases in others. Increases in collection rates were seen in the 1-4, 5-14 and 75+ 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 53,000 new cases in England last week (range 26,000 to 114,000) 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 715,000 (with a range 336,000 to 1,483,000) 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 46 (ending 15 November) GP consultation rates for flu-like illness in England have shown a small decrease compared to the previous week (37.8 per 100,000 in week 45 to 35.9 per 100,000 in week 46) 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 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 47.2 per 100,000 in week 45.to 48.4 per 100,000 in week 46. 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.

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 46 (ending 15 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 45 this week (week 46) rates have increased in all age bands except the 15-24 and 25-44 age bands where the rates have decreased. The largest increase (38%) was seen in the 5-14 year old age band.

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 18 November 2009) 3,359 viruses have been analysed by the Centre for Infections for the genetic marker commonly associated with resistance to oseltamivir in seasonal H1N1 flu (H274Y). 12 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 antivirals. In addition, 293 specimens have been fully tested for susceptibility. 

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 18 November). 

Deaths - the number of deaths related to swine flu in England is 142 (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 16 November 2009)

Total deaths reported: 7,051 

In the last 7 days, the total number of deaths reported globally has increased by 7% - a small increase from the figure reported last 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 13 November that for:

• Tropical regions: Most countries in the tropical region of Central and South America continue to report declining influenza activity. Overall transmission continues to decline in most parts of South and Southeast Asia, with the exception of Nepal and Sri Lanka.
• Western Asia: increasing activity has been observed in several countries including Israel and Afghanistan
• Temperate northern hemisphere regions: The winter influenza season, which began unusually early across much of the Northern Hemisphere, shows early signs of peaking in parts of North America but is intensifying across much of Europe and Central and Eastern Asia..
  • In Europe and Central Asia: overall influenza transmission continues to intensify as pandemic activity spreads eastward. At least 10 countries in Western Europe (Iceland, Poland, Romania, Belgium, Germany, the Netherlands, Norway, Spain, Sweden and the United Kingdom) now report active circulation of pandemic influenza viruses. High to very high intensity of respiratory diseases with concurrent circulation of pandemic H1N1 2009 was also reported in the Netherlands, Italy, much of Northern Europe, Belarus, Bulgaria, and in the Russian Federation (particularly in the Urals). Disease activity may be peaking in a few countries, notably Iceland and Ireland that experienced intense transmission during early autumn. The Ukraine has experienced a sharp rise in the number of cases, however this does not appear to represent a change in the transmission or virulence of the virus. Preliminary investigation of samples taken from patients in the Ukraine has not revealed significant changes in the pandemic (H1N1) 2009 virus.
  • Canada has reported sharp increases in rates of influenza-like-illness (ILI), detections of pandemic H1N1 2009 virus, and school outbreaks over the past three weeks as pandemic activity continues to spread eastwards. In the United States, influenza transmission remains geographically widespread and intense, however, disease activity may have peaked in southern and south eastern areas. In Mexico, influenza activity remains geographically widespread with a significant wave of cases reported since early September, most notably from central and southern Mexico.
• Africa: Somalia, Nigeria and Burundi have reported their first confirmed cases of pandemic (H1N1) 2009.
  More information on the latest global situation can be found on the WHO website at: http://www.who.int/csr/don/2009_11_13/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: 19 May 2010