SEASONAL INFLUENZA

What is Flu ?
● Flu (influenza) is a highly contagious respiratory infection caused by the influenza virus.
●   It is mainly transmitted via respiratory droplets in the air produced by coughing or sneezing.
●   Seasonal influenza is characterised by a sudden onset of high fever, cough (usually dry), headache, muscle and joint pain, severe malaise (feeling unwell), sore throat and runny nose.
●   For most people, the infection causes several days of acute illness followed by a complete recovery. For some, though, flu can be lead to more serious illnesses, such as pneumonia, which can be fatal. Those at high risk of suffering complications are people with underlying medical conditions and those who are less able to cope because of their age.
● Influenza occurs most often in winter and usually peaks between December and March in the northern hemisphere.

There are two major types of flu virus: influenza A, generally the cause of more serious illness, and influenza B.

The difficulty in combating flu occurs because the viruses can change their identity.
This may be a slight change (a drift) meaning that individuals no longer have immunity to the virus, resulting in outbreaks of illness. Alternatively, the virus can change identity very significantly (a shift) which may result in a worldwide epidemic of flu - a pandemic.

How serious is Flu ?
●   Deaths as a direct result of flu infection are often under-reported[1] because flu is not documented as the cause of death on the death certificate. Instead, the death may be attributed to pneumonia or other causes.
●   Even in non-epidemic years as many as 3,000 to 4,000 excess deaths are attributable to flu in the UK. During epidemics this level is much higher – for example during the epidemic of 1989-90 there were more than 23,000 excess deaths in England and Wales as a result of flu.[2]
●   In 2008/09, the peak rate of seasonal flu activity was higher than any year since 1999/2000, with GP consultations one third higher than in 2007/08. Nevertheless, this was still only a quarter of the rate seen in 1999/2000.[3]

Flu vaccination
●   Each year the World Health Organisation (WHO) announces the strains of flu virus which their reference laboratories have identified throughout the world as the likely cause of outbreaks during the following winter. To date, the WHO recommendations have shown a good match between the forecast strains and the actual strains which cause the outbreaks.
●   The flu vaccines which are currently available are clinically effective and give 70-80% protection against infection with strains related to those contained in the vaccine.[2]
●   Repeat annual vaccination is necessary due to the changing strains.[2]
●   Vaccination reduces the possibility of death as a result of flu infection by as much as 69%.4 and prevents 43-57% of deaths from influenza associated respiratory illness.[5]
●   Generally, the risks of serious complications and death associated with seasonal influenza can be avoided through repeated annual flu vaccination.[2]

Who should be offered seasonal flu vaccination ?
According to the influenza immunisation program for 2009/10, groups recommended to receive influenza vaccine remain unchanged from last year.
Influenza vaccination should be offered to: [6]
1. All those aged 65 and over
2. All those aged 6 months and over in a clinical risk group*
3. Those living in long-stay residential care homes or other long-stay care facilities where rapid spread is likely to follow introduction of infection and cause high morbidity and mortality(this does not include prisons, young offender institutions, university halls of residence etc)
4. Those who are in receipt of a carer’s allowance or those who are the main carer for an elderly or disabled person whose welfare may be at risk if the carer falls ill. This should be given on an individual basis at the GP’s discretion in the context of other clinical risk groups in their practice
*clinical risk groups are defined as those with:
● Chronic respiratory disease (including asthma that requires continuous or repeated use of inhaled or systemic steroids or with previous exacerbations requiring hospital admission)
● Chronic heart disease
● Chronic renal disease
● Chronic liver disease
● Chronic neurological disease, including stroke and transient ischaemic attack (TIA)
● Diabetes, type 1 and type 2 requiring insulin or oral hypoglycaemic drugs and diet controlled diabetes
● Immunosuppression due to disease or treatment

As well as offering flu vaccine to people in the groups above, GPs should take into consideration the risk of influenza infection exacerbating any underlying disease that a patient may have, as well as the risk of serious illness from influenza itself. GPs should also assess, for example, the clinical needs of individuals with multiple sclerosis and related diseases, or hereditary and degenerative diseases of the Central Nervous System.

Note: Target groups are generally consistent throughout the UK, however, there is some variation in implementing strategies across the four nations.

What level of vaccination is currently achieved ?
In the 2008/09 flu season approximately 14 million doses of vaccine were distributed throughout the UK, similar to the number expected to be available for the 2009/10 season.[7]
For the sixth consecutive year, the flu vaccine uptake rate amongst the over 65s was above 70%, but once again fell slightly short of the WHO 2010 target of 75%. Meanwhile, uptake amongst the clinical risk groups under 65 years of age improved on the previous year to 47.1%, however, increase in vaccine uptake in these groups remains a focus for 2009/10.[6]

Many people do not realise that they are at risk from flu and there is much that the medical profession and the media could do to inform and educate on the methods which may be utilized to increase vaccine uptake. An increase in flu vaccine uptake could mean that the complications of this vaccine preventable disease might be avoided and many lives may be saved every year.

References
1. Madjid et al. Influenza Epidemics and Acute Respiratory Disease Activity are
Associated with a Surge in Autopsy-Confirmed CHD Death Eur Heart J 2007 28(10):1205-1210;
2. Salisbury DM & Begg NT (Eds.). 1996 Immunisation Against Infectious Disease.
HMSO, chapter 19 - Influenza, updated December 2006 http://www.dh.gov.uk/prod_consum_dh/
groups/dh_digitalassets/@dh/@en/documents/digitalasset/dh_102825.pdf
3. Flu watch – Winter 2008/09 Department of Health website: CMO features http://www.dh.gov.uk/en/Aboutus/MinistersandDepartmentLeaders/ChiefMedicalOfficer/Features/DH_094790
4. NHS Centre for Reviews and Dissemination, University of York, Influenza
Vaccination and Older People. Effectiveness Matters 1996; 2: Issue 1
http://www.york.ac.uk/inst/crd/EM/em21.pdf
5. Fedson et al. Clinical Effectiveness of Influenza Vaccination in Manitoba. JAMA
1993; 270(16):1956-1961.
6. Donaldson, Sir Liam. Beasley, Prof Christine, Ridge, Dr Keith. The Influenza
Immunisation Programme 2009/2010. From the Chief Medical Officer, the Chief
Nursing Officer and the Chief Pharmaceutical Officer, 3 April 2009 http://www.dh.gov.uk/prod_consum_dh/groups/dh_digitalassets/documents/digitalasset/dh_097535.pdf
7. Hansard Archives 19 May 2009 Written Answers http://www.publications.parliament.uk/pa/cm200809/cmhansrd/cm090519/text/90519w0025.htm#column_1375W

Useful Links
http://www.dh.gov.uk/en/Publichealth/Flu/Flugeneralinformation/DH_137
http://www.dh.gov.uk/en/Publichealth/Healthprotection/Immunisation/Greenbook/index.htm
http://www.immunisation.nhs.uk/Vaccines/Flu/
http://www.who.int/topics/influenza/en/
http://www.ifpma.org/Influenza/index.aspx?60

UK VACCINE INDUSTRY GROUP