PANDEMIC INFLUENZA
Influenza (flu)
Flu (influenza) is a respiratory infection caused by the influenza virus. It is transmitted by droplets of respiratory secretions from person to person (through coughs and sneezes) and there is a period of two to three days before the disease becomes apparent. The symptoms of flu include fever, headache, cough, sore throat and aching muscles and joints. For most people the infection causes several days of acute illness followed by a complete recovery.
For some patients with underlying medical conditions, those who are less able to cope because of their age, or even young and healthy individuals flu can be followed by serious complications such as pneumonia, which can be fatal.
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. This happens in most years, and many people are vaccinated regularly against “seasonal” flu.
Flu viruses can also change their identity very significantly (a shift) which may result in a worldwide epidemic of flu as no-one has immunity to this type - this is a pandemic.
What is swine flu?
A new strain of Influenza A (H1N1), also known as swine flu, was initially identified in Mexico. Cases were confirmed in the UK in April and this disease has spread to more than 100 countries around the world.
Although symptoms have generally proved mild, a small number of patients have developed more serious illness. Many of these people have other underlying health conditions, such as heart or lung disease, that put them at increased risk of complications.
As with any sort of influenza, how severe the symptoms are and how long they last will depend on treatment and the patient’s individual circumstances.
What is a pandemic and what does this mean?
An epidemic is a sudden outbreak of disease that spreads through a single population or region in a short amount of time.
A pandemic occurs when there is a rapidly-spreading epidemic of a disease that affects most countries and regions of the world. This new strain of flu is now a pandemic.
Pandemic flu occurs when an influenza virus emerges that is so different from previously circulating strains that few, if any, people have any immunity to it. This allows it to spread widely and rapidly, causing serious illness.
Who is at risk from this disease?
Some groups of people are more at risk of serious illness if they catch flu. For seasonal flu the following groups of people are known to be at increased risk:
• pregnant women
• people aged 65 years and older
• young children under five years old
• People suffering from the following illnesses are also at increased risk:
o chronic lung disease
o chronic heart disease
o chronic kidney disease
o chronic liver disease
o chronic neurological disease
o Immunosuppression (whether caused by disease or treatment)
o Diabetes mellitus
o patients who have had drug treatment for asthma within the past three years
For swine flu, health authorities are still learning about specific risk groups, but they appear to be similar to risk groups for seasonal flu, except people aged 65 years and older may be less likely to suffer serious illness from swine flu. This may be due to older persons previously being exposed to influenza viruses that give partial protection against the swine flu virus. The pattern of risk groups against swine flu may change over time as the pandemic evolves.
Can the spread of this disease be prevented?
Swine flu, like seasonal flu, is easily spread by the tiny droplets in a cough or sneeze. By taking a few simple steps people can help to reduce the risk of catching flu and to stop the virus spreading.
To reduce the risk of catching or spreading the virus you should:
• cover your mouth and nose when coughing and sneezing, using a tissue
• throw the tissue away quickly and carefully
• wash your hands regularly with soap and water
• clean hard surfaces (like door handles and remote controls) frequently with a normal cleaning product
Vaccination
As this strain of flu is a new virus, a new vaccine had to be developed to protect people against it.
A number of different companies have received samples of the virus from the World Health Organisation, and are developing vaccines against it.
The first batch of vaccine is expected to be available in early autumn 2009, with significant quantities planned to be supplied by the end of the year.
The government has ordered enough vaccine for the whole population, but to reduce the impact of the disease those at greatest risk will be given priority.
More information
Directgov – The official UK government website for citizens – www.direct.gov.uk
World Health Organisation – The United Nations public health arm – www.who.int
Health Protection Agency – An independent UK body that aims to protect the health and well-being of the population – www.hpa.org.uk
NHS Choices – An Information Service intended to help people make health and lifestyle choices – www.nhs.uk
UK VACCINE INDUSTRY GROUP