Pandemic flu
Published by Bupa's health information team, April 2009.
This factsheet is for people who would like information about pandemic flu.
A pandemic is a global outbreak of a disease that affects numerous populations or countries.
A flu pandemic happens when a new version of the flu virus emerges and spreads easily and quickly across the world. Most people will have little or no immunity to this virus, and there will be no vaccine ready for use.
- About pandemic flu
- Symptoms of pandemic flu
- Causes of pandemic flu
- Treatment of pandemic flu
- Prevention of pandemic flu
- Vaccines for pandemic flu
- Further information
- Questions and answers
- Related topics
- Sources
About pandemic flu
A pandemic is a global outbreak of a disease that affects numerous populations or countries. In the last century there have been four flu pandemics - Spanish flu in 1918 and 1919, Asian flu in 1957 and 1958, Hong Kong flu in 1968 and 1969 and the current H1N1 pandemic.
Pandemic flu only occurs when the flu virus:
- is a new version of the virus, which has not been seen before
- affects humans and causes serious symptoms
- is very easily and quickly spread around the world
Pandemic flu is similar to 'ordinary' (seasonal) flu but the symptoms may be more severe and more people will be affected. 'Ordinary' flu is seasonal and tends to affect people around winter, but pandemic flu can happen at any time.
A flu pandemic can affect anyone, even if they are fit and healthy. Some groups of people may be more at risk during a flu pandemic, but scientists aren't able to say who these might be until a pandemic starts. It's also difficult for experts to predict how many people will be affected. A flu pandemic could happen in two or more waves, a few months apart. However, modern transport and overcrowded conditions could allow a pandemic to spread quicker than expected.
The World Health Organisation (WHO) monitors flu worldwide and has developed six alert phases to track pandemic flu.
Inter-pandemic period - the virus is in animals but not humans |
|
Phase 1 |
Low risk of human cases |
Phase 2 |
Higher risk of human cases |
Pandemic alert period |
|
Phase 3 |
No, or very limited, human-to-human transmission |
Phase 4 |
Evidence of increased human-to-human transmission |
Phase 5 |
Evidence of significant human-to-human transmission |
Pandemic period |
|
Phase 6 |
Efficient and sustained human-to-human transmission |
In the UK, phase six has been split into four sections.
- UK alert level 1: No cases in the UK
- UK alert level 2: Virus isolated in the UK
- UK alert level 3: Outbreak(s) in the UK
- UK alert level 4: Widespread activity across the UK
Symptoms of pandemic flu
The symptoms of pandemic flu are similar to seasonal flu but may be more severe. Seasonal flu usually affects your nose, throat, sinuses and airways. Symptoms can include:
- fever or chills
- coughing or wheezing
- headache
- sore throat
- feeling tired
- sore muscles
- a blocked or runny nose
If you have flu symptoms during a pandemic, don't visit your GP. You should follow government advice about returning to work or school if you have flu symptoms during a pandemic.
Causes of pandemic flu
Flu is caused by three groups of viruses - influenza A, B and C. The influenza viruses in groups B and C only affect humans. The influenza A group can affect birds, pigs and horses as well as humans, and these viruses may be able to transfer from one species to another.
A flu pandemic can happen if there is a more dramatic change to the virus than is normally seen every year. It can also happen if there is a change to the virus that is caused by a mix of strains of flu from different species. This is called an antigenic shift. This mix of genes can make a new, unique virus that no one will be immune to.
Treatment of pandemic flu
Antivirals
Antiviral medicines are sometimes used to treat the flu. However, until a flu pandemic starts, doctors can't be sure that antiviral medicines will work with that particular flu virus. Antiviral medicines can't stop you getting the flu, but they could reduce the symptoms and the length of time you are ill. The medicines are only effective if you take them within 48 hours of being exposed to the virus or of your symptoms starting. Antivirals are normally only recommended for people who are at a higher risk.
Antibiotics won't help with flu symptoms, or reduce the length of time you are unwell.
Self help
If you have flu symptoms, you shouldn't visit your GP. There are a number of things you can do at home to help reduce your symptoms.
- Drink enough fluids to prevent dehydration.
- Stay at home and rest.
- Take over-the-counter medicines such as paracetamol, aspirin or ibuprofen.
Always read the patient information leaflet that comes with your medicine and if you have any questions, ask your pharmacist for advice. Children under 16 years old should not be given aspirin or any medicines containing aspirin.
You should also follow government advice on treating the flu during a pandemic.
Prevention of pandemic flu
Pandemic flu can't be prevented but there are a number of things you can do to limit the spread of the virus.
The flu virus is spread from person to person as droplets in the air. Sneezing or coughing produces more droplets and helps to spread the infection. Touching infected surfaces, such as door handles or shaking hands, and then passing the virus from your hands to your mouth, nose or eyes is another route of infection.
To help stop the spread of pandemic flu, and to reduce your chances of becoming unwell, you should:
- cover your nose and mouth with a tissue when you cough or sneeze
- where possible, put used tissues in a bag and then in the bin as quickly as you can
- wash your hands with soap and water as often as you can
- clean hard surfaces like door handles and desks frequently with a normal cleaning product
- stay away from large crowds of people
- not travel unless it's necessary
You should also follow government advice on general hygiene during a pandemic.
Vaccines for pandemic flu
Seasonal flu changes a little from year to year, which makes it easier to predict the strain of the virus. This means that vaccines can be developed and given out at the right time. Pandemic flu can't be predicted and because it is a new virus, a vaccine can't be made until it has emerged.
The Department of Health estimates that it takes four to six months to develop a vaccine after a flu pandemic has started. In the UK, pharmaceutical companies have been signed up to start work on this as soon as a pandemic starts.
The priority groups for the vaccine are under constant review and are confirmed during a pandemic. It's likely that healthcare workers will be one of the priority groups. The Department of Health is responsible for distributing the vaccine to the UK.
If you get a flu vaccine each year, this won't protect you against pandemic flu.
Further information
- Department of Health
www.dh.gov.uk - HM Government
www.preparingforemergencies.gov.uk - World Health Organisation
www.who.int
Related topics
Sources
- Bird flu and pandemic influenza: what are the risks? Chief Medical Officer. www.dh.gov.uk, accessed 21 January 2009
- About pandemic flu. Department of Health. www.dh.gov.uk, accessed 20 January 2009
- Pandemic influenza. Health Protection Agency. www.hpa.org.uk, accessed 20 January 2009
- Influenza - background information: how does pandemic influenza differ from ordinary influenza? Clinical Knowledge Summaries. www.cks.library.nhs.uk, accessed 20 January 2009
- Pandemic flu. London Resilience Partnership. www.londonprepared.gov.uk, accessed 20 January 2009
- Influenza. BMJ Clinical Evidence.www.clinicalevidence.com, accessed 20 January 2009
- Pandemic preparedness. World Health Organisation. www.who.int, accessed 21 January 2009
- Pandemic alert phases. Department of Health.. www.dh.gov.uk, accessed 20 January 2009
- Chief Medical Officer. Explaining pandemic flu: a guide from the CMO. London: Department of Health, 2005
- Influenza - making a diagnosis. Clinical Knowledge Summaries. www.cks.library.nhs.uk, accessed 20 January 2009
- Pandemic flu - frequently asked questions. Department of Health. www.dh.gov.uk, accessed 1 January 2008
- Pandemic flu. UK Resilience. www.ukresilience.gov.uk, accessed 20 January 2009
- Avian influenza (bird flu): questions & answers. Department for Environment Food and Rural Affairs. www.defra.gov.uk, accessed 21 January 2009
- Common cold - management. Clinical Knowledge Summaries. www.cks.library.nhs.uk, accessed 22 January 2009
This information was published by Bupa's health information team and is based on reputable sources of medical evidence. It has been peer reviewed by Bupa doctors. The content is intended for general information only and does not replace the need for personal advice from a qualified health professional.
Publication date: April 2009
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