Flu vaccine, seasonal

Seasonal flu is a highly infectious respiratory illness caused by a variety of different flu viruses. It spreads rapidly through droplets dispersed by the coughs and sneezes of infected people.

Each year, a vaccine is developed to protect against the strains of flu virus that are expected to be most prevalent that winter. This 'flu jab' is used not just in Ireland, but throughout the Northern hemisphere. It gives good protection (70-80% reliability) against all strains of flu included in the vaccination and lasts for a year.

The entire process of developing the seasonal flu vaccine is led, organised and overseen by the World Health Organization (WHO).

The flu jab is offered to people in at-risk groups. These are people, such as pregnant women and the elderly, who are at greater risk of developing serious complications if they develop flu.

You should check now to see if you or members of your family are in an at-risk group.

This year's flu jab (2017/18)

The World Health Organization (WHO) has recommended that this year's influenza vaccine contains the following strains:

  • an A/Michigan/45/2015 (H1N1)pdm09-like strain
  • an A/Hong Kong/4801/2014 (H3N2)-like strain
  • a B/Brisbane/60/2008-like strain

These are the strains estimated by WHO that are most likely to be circulating this year.
Further information is available at http://www.who.int/influenza/vaccines/virus/recommendations/2017_18_north/en/

Is the vaccine safe?

Flu vaccines have excellent safety records; the most common reactions are a sore arm or possibly feeling hot.

The most common side effects will be mild and may include soreness, redness or swelling where the injection was given. Headache, fever, aches and tiredness may occur. Some people may have mild sweating and shivering as their immune system responds to the vaccine, but this is not flu and will pass after a day or so.

It is also important to note that the flu vaccine cannot give you flu.

This year’s seasonal flu jab is no different to any other in terms of the risk it presents and has been thoroughly tested and approved for use in Ireland.

The HSE recommends that everyone who is eligible for a seasonal flu vaccine has it as soon as possible.

If you are in an at-risk group and do not have the jab, you will be at a greatly increased risk of developing serious complications or even dying if you contract flu this winter.

If you haven't had the seasonal flu vaccine and you are in a risk group, it isn't too late to make an appointment for the vaccine. 

For most people, seasonal flu is unpleasant but not serious and they recover within a week.

However, certain people are at greater risk of developing serious complications of flu, such as bronchitis and pneumonia. These conditions may require hospital treatment. A large number of elderly people die from flu every winter.

The seasonal flu vaccine is offered free of charge to at-risk groups to protect them from catching flu and developing serious complications.

At-risk groups

Vaccination is strongly recommended for:

Persons aged 65 and over
Those aged 6 months and older with a long-term health condition such as

  • Chronic heart disease (this includes anyone who has a history of having a "heart attack" or unstable angina)
  • Chronic liver disease
  • Chronic renal failure
  • Chronic respiratory disease, including chronic obstructive pulmonary disease (COPD), cystic fibrosis, moderate or severe asthma or bronchopulmonary dysplasia
  • Chronic neurological disease including multiple sclerosis, hereditary and degenerative disorders of the central nervous system
  • Diabetes mellitus
  • Down syndrome
  • Haemoglobinopathies
  • Morbid obesity i.e. body mass index (BMI) over 40
  • Immunosuppression due to disease or treatment, including asplenia or splenic dysfunction

Children aged 6 months and older

  • 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 with moderate to severe neurodevelopmental disorders such as cerebral palsy and intellectual disability
  • on long-term aspirin therapy (because of the risk of Reyes syndrome)

Pregnant women (vaccine can be given at any stage of pregnancy)
Healthcare workers
Residents of nursing homes and other long stay institutions
Carers (the main carers of those in the at risk groups)
People with regular contact with pigs, poultry or water fowl

Pregnant women

This winter it is recommended that all pregnant women should have the seasonal flu vaccine irrespective of their stage of pregnancy.

This is because there is good evidence to suggest that pregnant women have an increased risk of developing complications if they develop flu.

Studies have also shown that the inactivated flu vaccine can be safely and effectively administered during any trimester of pregnancy. The vaccine itself does not present an increased risk of complications to either the mother or baby.

Healthcare workers

Employers are responsible for ensuring that arrangements are in place for their healthcare staff to have the seasonal flu vaccine.

Outbreaks of flu can occur in health and social care settings with staff, patients and residents at risk of being affected.

Therefore, it is very important that healthcare workers protect themselves by having the flu vaccine and in doing so prevent the spread of flu to colleagues and other members of the community.

If you care for someone who is elderly or disabled, you should also be vaccinated against seasonal flu and you should ensure that the person you are caring for has the flu vaccine as well.

Flu vaccine eligibility: medical conditions

The seasonal flu vaccine is offered free of charge if you are in one of the following at risk groupings. 

  • The vaccine and consultation are free to those within the recommended groups who have a 'Medical Card' or 'Doctor Only Card'.
  • Family doctors and Pharmacists charge a consultation fee for seasonal flu vaccination to those who do not have a 'Medical Card' or 'Doctor Only Card'.

Vaccination is strongly recommended for:

Persons aged 65 and over
Those aged 6 months and older with a long-term health condition such as

  • Chronic heart disease (this includes anyone who has a history of having a "heart attack" or unstable angina)
  • Chronic liver disease
  • Chronic renal failure
  • Chronic respiratory disease, including chronic obstructive pulmonary disease (COPD), cystic fibrosis, moderate or severe asthma or bronchopulmonary dysplasia
  • Chronic neurological disease including multiple sclerosis, hereditary and degenerative disorders of the central nervous system
  • Diabetes mellitus
  • Down syndrome
  • Haemoglobinopathies
  • Morbid obesity i.e. body mass index (BMI) over 40
  • Immunosuppression due to disease or treatment, including asplenia or splenic dysfunction

Children aged 6 months and older

  • 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 with moderate to severe neurodevelopmental disorders such as cerebral palsy and intellectual disability
  • on long-term aspirin therapy (because of the risk of Reyes syndrome)

Pregnant women (vaccine can be given at any stage of pregnancy)
Healthcare workers
Residents of nursing homes and other long stay institutions
Carers (the main carers of those in the at risk groups)
People with regular contact with pigs, poultry or water fowl

If you have a ‘Medical Card’ or ‘GP Visit Card’ the vaccine and consultation are free.

If you do not have a ‘Medical Card’ or ‘GP Visit Card’ you will be charged a consultation fee for seasonal flu vaccine.

Who should not have the seasonal flu jab?

The vaccine should not be given to those with a history of severe allergic reaction (anaphylaxis) to a previous dose of the vaccine or any of its constituents.

Generally, if you are healthy, under 65 years of age and do not fall into any of the high risk groups it is not necessary for you to have a flu jab as your body can fight off the virus if you become ill with it.

If you are ill with a high fever, do not have your flu jab until you have recovered.

If you think you need a seasonal flu vaccination (see Who should have it), check with your GP, nurse, local pharmacist or occupational health department.

Most GP surgeries or local pharmacies organise special vaccination sessions in the autumn.

The flu virus circulates every winter, usually over a period of a few weeks. The best time to have a flu jab is in the autumn, between late September and early November. Do not wait until the winter, when there is already a flu epidemic.

Glossary

Epidemic
An epidemic is a sudden outbreak of disease that spreads through a population in a short amount of time.
Vaccination
Vaccination or immunisation is usually given by an injection that makes the body's immune system produce antibodies that will fight off a virus.

How the flu vaccine composition is decided

The World Health Organization (WHO) decides each February which three flu viruses are likely to be the greatest threat that year.

The decision is made by analysing several thousand flu viruses in the WHO flu laboratories around the world. These laboratories assess which strain has been dominant over the previous winter and look for evidence of new strains that have the potential to spread, and how well the current vaccine protects against them.

Production of the vaccine starts in March each year after the WHO announcement. It is available in Ireland from September onwards. 

How it protects you

About a week to 10 days after you have had the flu injection, your body starts making antibodies to the virus in the vaccine.

Antibodies are proteins that recognise and fight off germs that have invaded your blood, such as viruses. They help protect you against any similar viruses you then come into contact with.

The flu virus changes every year, so you need to have a flu jab annually to make sure that you are protected against the latest strain of the virus.

Glossary

Antibodies
Antibodies and immunoglobins are proteins in the blood. They are produced by the immune system to fight against bacteria, viruses and disease.
Fever
A high temperature, also known as a fever, is when someone's body temperature goes above the normal 37°C (98.6°F).
Allergic
An allergen is a substance that reacts with the body's immune system and causes an allergic reaction.
Aches
An ache is a constant dull pain in a part of the body.
Immunisation
Vaccination or immunisation is usually given by an injection that makes the body's immune system produce antibodies that will fight off a virus.

Are there any side effects?

The seasonal flu jab does not usually cause side effects.

Sometimes, it can cause mild fever and slight muscle aches for a day or so.

Flu vaccine cannot cause flu, as there is no active virus in a flu vaccine. However, people sometimes catch other flu-like viruses, or very occasionally catch flu before the vaccine takes effect.

Allergic reactions to the vaccine are rare.

Content provided by NHS Choices www.nhs.uk and adapted for Ireland by the Health A-Z.

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