Influenza is a highly infectious acute respiratory illness caused by the influenza virus. Influenza affects people of all ages. Outbreaks of influenza occur almost every year, usually in winter. This is why it is also known as seasonal flu.
Flu is often self limiting with most people recovering in 2-7 days. However, flu can be severe and can cause serious illness and death, especially in the very young and in the elderly. Serious respiratory complications can develop, including pneumonia and bronchitis, to which older people and those with certain chronic medical conditions are particularly susceptible. Serious respiratory complications can develop, including pneumonia and bronchitis, to which older people and those with certain chronic medical conditions are particularly susceptible. Pregnant women have also been found to be at increased risk of the complications of flu. Some people may need hospital treatment and a number of mainly older people die from influenza each winter.
Flu is a highly infectious illness. A person carrying the virus can spread the illness by coughing or sneezing. A person can spread the virus from 1-2 days before they develop symptoms and for up to a week after symptoms develop.
Flu symptoms hit you suddenly and severely. Symptoms of flu include
- sudden fever,
- chills,
- headache,
- myalgia (muscle pain),
- sore throat
- non-productive dry cough.
It can be difficult at times to tell between the common cold and flu. A cold is a much less severe illness than flu. The flu symptoms come on suddenly with fevers and muscle aches. A cold usually starts gradually with symptoms of a sore throat and a blocked or runny nose.
The following table provides information on how to distinguish between seasonal flu and cold symptoms.
Symptoms |
Seasonal flu |
Cold |
Fever |
High fever lasts 3-4 days |
Rare |
Headache |
Prominent |
Rare |
General Aches, Pains |
Usual; often severe |
Slight |
Fatigue, Weakness |
Can last up to 2-3 weeks |
Quite mild |
Extreme Exhaustion |
Early and prominent |
Never |
Stuffy Nose |
Sometimes |
Common |
Sneezing |
Sometimes |
Usual |
Sore Throat |
Sometimes |
Common |
Chest Discomfort, Cough |
Common; can become severe |
Mild to moderate; hacking cough |
Anyone can get the flu but it is more severe in people aged 65 years and over and anyone with a chronic medical condition. Chronic medical conditions include chronic heart conditions, chronic respiratory disease, diabetes mellitus and immunosupression due to disease or treatment. Pregnant women have also been found to be at increased risk of the complications of flu. These groups of people are targeted for influenza vaccination.
Flu can be prevented by vaccination. Flu vaccine is a safe, effective way to help prevent flu infection, avoiding hospitalisation, reducing flu related deaths and illnesses.
Each year the seasonal (annual) flu vaccine contains three common influenza virus strains. The flu virus changes each year this is why a new flu vaccine has to be given each year. This year’s flu vaccine contains the Swine Flu strain.
This year’s seasonal flu vaccine contains 3 strains of flu viruses as recommended by the World Health Organization (WHO) and has been manufactured in a similar way to previous seasonal vaccine. The three strains are
- A/California/7/2009 (H1N1)-like virus (the pandemic H1N1 2009 virus)
- an A/Perth/16/2009 (H3N2)-like virus;
- a B/Brisbane/60/2008-like virus
Vaccination is strongly recommended for:
- all those aged 65 years and older
- pregnant women (vaccine can be given at any stage of pregnancy)
- adults and children* over 6 months of age with any of the following
- chronic illness requiring regular follow up (e.g. chronic respiratory disease including cystic fibrosis, moderate or severe asthma, chronic heart disease, chronic neurological disease, diabetes mellitus, chronic liver disease, chronic neurological disease including multiple sclerosis, hereditary and degenerative disorders of the central nervous system etc)
- those who are immunosuppressed due to disease or treatment including those with missing or non functioning spleens
- those with morbid obesity i.e. Body Mass Index over 40
- healthcare workers
- residents of nursing homes, and other long stay institutions
- carers
- people who have close, regular contact with pigs, poultry or water fowl
- children* with any condition (e.g. cognitive dysfunction, spinal cord injury, seizure disorder, or other neuromuscular disorder) that can compromise respiratory function especially those attending special schools/ day centres
- children* and teenagers* on long-term aspirin therapy (because of the risk of Reyes syndrome)
(*only adults over 18 will be vaccinated as part of Hickey’s Flu Vaccination campaign Children should receive the vaccine from their GP)
How does seasonal flu vaccine work?
Seasonal flu vaccine helps the person’s immune system to produce antibodies to the flu virus. When someone who has been vaccinated comes into contact with the virus these antibodies attack the virus.
Swine Flu is a new flu virus that first emerged in April 2009. As most people did not have any immunity against this virus it spread rapidly worldwide and infected a large number of people. It is also known as Pandemic H1N1 (2009). Swine Flu infected in particular young children, pregnant women, women up to 6 weeks after giving birth and those under 65 years with long term medical conditions.
It is likely that the Swine Flu strain will be the predominant strain circulating this season. However we cannot be 100% certain of this and the WHO makes its recommendations based on expert advice and this is why the seasonal flu vaccine offers protection against three strains.
There are no safety concerns of administering the seasonal flu vaccine to those who have previously received Swine Flu vaccine.
Seasonal flu vaccines have been given for more than 60 years to millions of people across the world. Reactions are generally mild and serious side effects are very rare. The seasonal flu vaccines cannot give you the flu.
No, flu vaccine will not give you the flu. Flu vaccine contains killed or inactivated viruses and therefore cannot cause flu. It does, however, take 10 – 14 days for the vaccine to start protecting against flu.
The vaccine should be given in late September/October each year.
The most common side effects will be mild and will include soreness, redness or swelling where the injection was given. Headache, fever, aches and tiredness may occur. Some people may experience mild sweating and shivering as their immune system responds to the vaccine but this is not flu and will pass in a day or so.
The vaccine starts to work within two weeks.
The vaccine should not be given to those with a history of severe allergic (anaphylaxis) reaction to a previous dose of the vaccine or any of its constituents.
People with egg allergy can get seasonal flu vaccine. This may be given by your GP or you may need referral to a hospital specialist.
There are very few reasons why vaccination should be postponed. Vaccination should be re-scheduled if you have an acute illness with a temperature greater than 38°C.
This is an infectious viral infection of birds and less commonly pigs.
Avian or bird flu due to the H5N1 virus has spread rapidly throughout poultry flocks in Asia and more recently to Eastern Europe. It is proving difficult to eradicate in birds.
Humans are rarely affected with avian/bird flu and this has mainly happened through close contact with live infected birds or their faeces.
Seasonal flu vaccine doesn't protect against avian influenza and there is no vaccine currently licensed against avian influenza.
REMEMBER!
If you are over 65 or have a long term medical condition you should also ask your doctor about the pneumococcal vaccine which protects against pneumonia, if you have not previously received it.
Keep well this winter
- Eat well: eat at least one hot meal a day.
- Keep warm: wear several layers when outside and keep at least one room heated during the day.
- Keep active.
- Get vaccinated.
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