Weekly pandemic flu media update
10 September 2009
KEY POINTS
- This week there has been a further reduction in the rates of flu-like illness and related activity.
- Weekly GP consultation rates continued to decrease over the last week in England.
- The majority of cases continue to be mild. There is still no sign that the virus is changing.
- 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 3,000 new cases in England last week (range 1,500 to 6,500).
This estimate incorporates data from National Pandemic Flu Service and GP consultations. - Many countries in the southern hemisphere have now passed the peak of their winter flu epidemic. Flu activity in Australia is now returning to baseline levels and in total there have been 35,897 confirmed cases and 165 deaths.
- Serological studies conducted at the WHO collaborating centres suggest that a proportion of older adults have some level of cross-reactive neutralizing antibodies to the pandemic H1N1 2009 virus (www.who.int/wer/2009/wer8436.pdf)
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 36 (ending 06 September) GP consultation rates for flu-like illness in England decreased compared to the previous week (11.8 per 100,000 to 8.6 per 100,000). The rate continued to decrease in North (4 per 100,000) and Central (10 per 100,000) regions but stayed stable and low in the South (10 per 100,000). The rate has decreased in all age groups.
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 decreased from 14.4 per 100,000 to 10.9 per 100,000 in week 36. The daily rate for flu-like illness for the last few days remained low and continued to decrease slowly 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 36 (ending 06 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. The trend in the <1 year age group is decreasing more than in other age groups. NB: <1 year olds are not considered by the National Pandemic Flu Service and always referred to a GP.
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
Viral characteristics (including antiviral susceptibility (as at 09/09/09): Testing for antiviral susceptibility is carried out by the Agency's Respiratory Virus Unit, Centre for Infections, in Colindale. 839 viruses have been analysed for the marker commonly associated with resistance to oseltamivir in seasonal influenza (H274Y); none were found to carry this marker. In addition, 252 specimens have been fully tested for susceptibility; all were found to be sensitive to oseltamivir and zanamivir.
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: 132 patients (currently hospitalised as of 8am on 09 September).
Deaths - the number of deaths related to swine flu in England is 66. (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 08 September 2009)
|
Total deaths reported |
3,491 |
In the last 7 days, the total number of deaths reported globally has increased by 19% - a similar increase to those seen over 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.
General trends
In tropical regions there is variation between countries within regions though general trends in respiratory disease are continuing to increase in many tropical areas of South and Southeast Asia and South America, while mainly decreasing in Central America and the Caribbean. All these regions continue to experience regional or widespread flu activity.
In temperate southern hemisphere regions many countries have now passed the peak of their winter flu epidemic though sustained flu activity continues to be reported in South Africa and in the Southern and Western parts of Australia.
In temperate northern hemisphere regions there are wide geographical variations in the level of flu activity being reported. Flu activity continues to show an early increase past the seasonal epidemic threshold in Japan. In Canada and the United States, flu activity remains low overall, though with regional increases in the Southeastern United States. In Europe and Central and Western Asia, although little flu activity is being reported, a few countries are reporting geographically widespread flu activity (Austria and Israel) or an increasing trend in respiratory diseases (Netherlands and Romania).
Source: WHO Disease Outbreak News
http://www.who.int/csr/don/2009_09_04/en/index.html
Pandemic (H1N1) influenza virus continues to be the predominant circulating flu virus, both in the northern and southern hemisphere, accounting for 61% of all flu detected in week 34. All pandemic H1N1 2009 influenza viruses analysed to date have been antigenically and genetically similar to A/California/7/2009-like pandemic H1N1 2009 virus.
Serological studies conducted at the WHO collaborating centres (WHOCC) suggest that a proportion of older adults have some level of cross-reactive neutralizing antibodies to the pandemic H1N1 2009 virus (www.who.int/wer/2009/wer8436.pdf):
Data from a study in Japan showed that 40% of 30 elderly persons (aged 72-103 years; average 83 years) had neutralizing antibody titers of >40 against the pandemic virus. Data from the USA showed that children and younger adults aged <30 years had little or no cross-reactive antibodies to human infection with pandemic A (H1N1) 2009 influenza virus, but that cross-reactive neutralizing antibody titers of ?80 were detected in approximately one third of older adults (aged >60 years) tested.
WHO does not report any new information about clinical features, at risk groups, antiviral resistance or public health responses this week.
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: 10 September 2009
