Dr Caitlin: The Flu Vaccine And Who Should Get It

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Dr Caitlin O’Connor of Tralee Medical Centre in St Brendan’s Park on the flu vaccine and who should get it…

Who is most at risk from flu?

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 immunosuppression due to disease or treatment including all cancer patients.

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.

Continued below…


Who should be vaccinated?

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
Morbid obesity i.e. body mass index (BMI) over 40
Immunosuppression due to disease or treatment (these include anyone on treatment for cancer)

• Children aged 6 months and older

with any condition that can affect lung function especially those attending special schools/day centres with cerebral palsy or 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.

What is influenza (flu)?

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.

How serious is flu?

Flu is often self-limiting. Healthy people normally recover within 7 days but some people recover more quickly. People who are at risk of the complications of flu will usually feel better in about 10 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.

Pregnant women have also been found to be at increased risk of the complications of flu. Some people may need hospital treatment and between 200 and 500 people, mainly older people, die from influenza each winter.

How do people catch flu?

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 5 days after symptoms develop.

What are the symptoms of Flu?

Flu symptoms hit you suddenly and severely. Symptoms of flu include

• sudden fever,
• chills,
• headache,
• myalgia (muscle pain),
• sore throat,
• non-productive dry cough.

Is it seasonal flu or the common cold?

It can be difficult at times to tell between the common cold and flu, especially in older people.

A cold is a much less severe illness than flu. The flu symptoms come on suddenly with fevers and muscle aches, although older people often do not have fever.

A cold usually starts gradually with symptoms of a sore throat and a blocked or runny nose.

Table of Symptoms

The following table provides information on how to distinguish between seasonal flu and cold symptoms…



How can flu be prevented?

Flu can be prevented by vaccination. Flu vaccination is a safe, effective way to help prevent flu infection, avoiding hospitalisation, reducing flu related deaths and illnesses.

What is the seasonal (annual) flu vaccine?

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.

What strains are in the 2017/18 year’s seasonal flu vaccine?

This year’s seasonal flu vaccine protects against the 3 strains of flu virus recommended by the World Health Organization (WHO) as the strains most likely to be circulating this season. The three strains are;

• 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

How does the seasonal flu vaccine work?

Seasonal flu vaccination 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.

How effective is the seasonal flu vaccine?

Influenza vaccine effectiveness can vary from year-to-year among different age and risk groups.

How well the vaccine works can depend in part on the match between the predicted vaccine virus used to produce the vaccine and the viruses that will circulate during the 2017/2018 season. This year’s flu vaccine is expected to be around 60% effective.

How long is the flu season?

In the Northern hemisphere the flu season lasts from October to the end of April. Flu vaccination is recommended in order to protect all those in the at risk groups until the end of April.

Women who are pregnant at any stage during the flu season should get flu vaccine. The flu vaccine has been given during pregnancy for the past 50 years in the US.

How safe is the 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.

How long does it take the vaccine to work?

The vaccine starts to work within two weeks.

Is there thiomersal in the seasonal flu vaccine?

No. There is no thiomersal in the vaccine used in the 2017/2018 flu campaign.

Will the flu vaccine give me 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.

When should I get vaccinated?

The vaccine should be given in late September/October each year.

What should I expect after vaccination?

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.

How long does it take the vaccine to work?

The vaccine starts to work within two weeks.

Who should NOT get seasonal flu vaccine?

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.

What about people with egg allergy?

Those with confirmed egg anaphylaxis and non-anaphylactic egg allergy can be given an influenza vaccine with an ovalbumin content <0.1μg per dose.

Inactivated Influenza vaccine (Split Virion) BP (Sanofi Pasteur) contains less than 0.1μg ovalbumin per dose. This vaccine may be given by the GP or you may need referral to a hospital specialist.

When should vaccination be postponed?

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.


If you are aged 65 or older 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.

A once only booster vaccination is recommended 5 years after the first pneumococcal vaccination for those;

• Aged 65 years and older if they received vaccine more than 5 years before and were less than 65 years of age at the time of the first dose,

• Less than 65 years of age and whose antibody levels are likely to decline rapidly e.g. if you have any of the following medical conditions: an underactive spleen, or have had your spleen removed, immunosuppression, chronic kidney disease or kidney transplant.

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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