Seasonal flu levels trigger use of antiviral drugs

10 January 2008

As seasonal flu levels reach the point at which doctors are being advised to prescribe antiviral drugs to vulnerable patients, the Health Protection Agency North West is advising that it is not too late to get a flu jab.

National surveillance data published by the Agency indicates that the overall rate of influenza-like illness has exceeded the threshold at which the National Institute for Health and Clinical Excellence (NICE) guidance recommends that antiviral drugs be used in the treatment of patients who are at higher risk of developing complications from flu.

Professor John Watson , Head of the Respiratory Diseases Department at the Health Protection Agency , said: “ Our surveillance shows that since mid December this year seasonal flu activity in the country as a whole has started to increase to normal seasonal levels which the NICE guidelines refer to as the levels seen most winters.

“For most people, flu is miserable, lasting a week or so, but not life threatening. For those in at-risk groups, however, such as the elderly and patients with heart problems, diabetes or lung, liver or renal diseases, or those who have weak immune systems, it can be far more dangerous and can lead to more serious illnesses. ”

Dr. Rosemary McCann , Consultant in Communicable Disease Control with the HPA North West's Greater Manchester Health Protection Unit, said: “Flu rates are still comparatively low in the North West , but with evidence of increasing levels elsewhere in the country, there is no room for complacency. Anyone who is entitled to a free flu jab on the NHS should have one now, if they haven't had one already.

“Flu is not a bad cold. It is a serious illness and people are particularly vulnerable if they are aged 65 or over, have a chronic illness such as diabetes or asthma, or live together in close proximity in residential care homes.”

Professor Watson said: “Vaccination offers the best protection for those at high risk from seasonal influenza. Antivirals are only effective if taken within 48 hours of onset of symptoms. They may limit the impact of some symptoms and reduce the potential for serious complications. However, vaccination is the best way of avoiding infection when flu is circulating.”

People are eligible for a free flu jab on the NHS if they are:

• Aged 65 or older

• Live in long-stay residential homes

• Have a history of heart conditions, kidney disease, chronic asthma or diabetes that requires medication

• Have lowered immunity to infection as a result of HIV, steroid medication or cancer treatment

Symptoms of seasonal flu include sudden onset of fever with aching muscles and joints. Patients may also experience headache, cough or sore throat. People with flu are advised to rest, drink plenty of fluids and take pain-relievers such as paracetamol.

Good hygiene practice such as covering your nose and mouth with a tissue when coughing or sneezing is the most effective way, disposing of the tissue as soon as possible and cleaning your hands as soon you can are important actions that will help prevent the spread of germs and reduce the risk of transmission.

Although unpleasant, flu is a self-limiting illness. If you have flu it is best to stay away from work or school while ill to avoid infecting others. Individuals should seek medical advice if symptoms persist or become more severe.

-ends-

Notes to Editors:

Here's a summary of the North West flu rates per 100,000 of population: Baseline activity for this time of the year is 30 cases per 100,000 of population, so the North West figures are still well below baseline, although increasing. The flu rates given are for the first week in January 2008 with a comparison in brackets to the figures for week 52 of 2007.

North West – increase to 16.2 in week 1 (11.2 in week 52)

Cumbria & Lancashire – increase to 11.8 in week 1 (9.8 in week 52)

Greater Manchester – increase to 16.1 in week 1 (10.7 in week 52)

Cheshire & Merseyside – increase to 20.3 in week 1 (13.1 in week 52)

The national data shows an increase from 20.9 cases per 100,000 of in week 52 of 2007 to 31.4 per 100,000 in week 1 of 2008, which is what triggered the Department of Health to issue advice on the use of antiviral drugs. 15-44 year olds are most affected throughout the country with a rate of 43.7 cases per 100,000 of population in that age band in week 1 of 2008.

1. Antivirals are drugs given to high risk patients who become ill with seasonal influenza. They are only effective if taken within 48 hours of onset and may help limit the impact of some symptoms and reduce the potential for serious complications. They are also used in some situations where it is important to help prevent people from getting influenza. The NICE guidance applies only when the number of people with flu reaches a high-enough level and there is good evidence that flu is ‘circulating in the community'.

2. The Department of Health has now advised GPs to consider prescribing antiviral drugs where necessary in line with guidance issued from the National Institute for Health and Clinical Excellence (NICE). To see the current guidance please go to: www.nice.org.uk which has full guidance on the use of antivirals. It does not recommend antivirals for the prevention of flu in otherwise healthy people under 65, even if they have been in close contact with someone with a flu-like illness.

3. One of the primary methods used to monitor flu levels is through the Royal College of General Practitioners (RCGP) surveillance scheme. The scheme takes a sample of GPs from around the country and monitors the number of people per 100,000 who have consulted their GP for flu or flu-like illness throughout the winter. Similar schemes are conducted in Scotland , Wales and NI. One of the key ways the Agency provides interpretation of the data is through the use of ‘thresholds'. These provide a clear and consistent message about the levels of influenza virus circulation and provide an indication to GPs when sufficient virus is circulating to warrant the use of antiviral drugs.

The thresholds used to define the level of flu activity are:
‘baseline activity' (
‘normal seasonal activity' (30 – 200 consultations per 100,000)
‘epidemicactivity'(>200 consultations per 100,000 people).

4. Advice on flu is available from NHS Direct on 0845 4647 or www.nhsdirect.nhs.uk or local GP surgery. For further information on flu go to: http://www.hpa.org.uk/infections/topics_az/influenza/flu.htm.

5. Seasonal influenza occurs most often in winter and usually peaks between December and March in the northern hemisphere. The influenza virus is unstable and new strains and variants are constantly emerging. The predominant flu strain circulating this year is Influenza A with the subtype H1. The current flu vaccine offers good protect against this strain.

The current flu vaccine for this season includes:

an A/Solomon Islands/3/2006 (H1N1)-like virus
an A/Wisconsin/67/2005 (H3N2)-like virus*
a B/Malaysia/2506/2004-like virus

*A/Wisconsin/67/2005 (H3N2) and A/Hiroshima/52/2005

6. Seasonal flu vaccine is recommended for those aged 65 or over and those with the following conditions, regardless of age:

chronic respiratory disease
heart disease
renal disease and chronic liver disease
diabetes requiring insulin or oral hypoglycaemic drugs
immunosuppression.
multiple sclerosis, or conditions of the nervous system, or if you have had a stroke

Vaccination is also recommended for 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 offenders' institutions, or university halls of residence).

Vaccination is also recommended for carers defined as 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.

In addition, it is recommended that immunisation be offered to all health care workers involved in the delivery of care and/or support to patients. Social service employers have also been asked to consider offering immunisation to all staff involved in the delivery of care and/or support to clients.

The Department of Health vaccine programme takes place between October – December but high risk individuals may still be able to obtain vaccine from their GP if relevant.

7. Latest influenza data from the HPA can be found at:

http://www.hpa.org.uk/infections/topics_az/influenza/seasonal/flureports0708.htm

8. Further information on seasonal influenza can be found at:

http://www.hpa.org.uk/infections/topics_az/influenza/seasonal/default.htm

Last reviewed: 14 January 2009