Since 2020, despite the low risk from influenza for children, the HSE recommend annual vaccinations for those aged two and older, often administered through schools. The vaccine recommended is Fluenz Nasal Spray, manufactured by AstraZeneca (known as Flumist in the US). This is a live, attenuated virus vaccine containing three strains of flu (trivalent).
This article provides an overview of the potential risks associated with both the vaccine and the disease it targets, helping you make an informed decision.
Disease versus Vaccine Risk Summary
Risk from Influenza for Children Under 5
| Category | Details |
|---|---|
| Risk of admission to ICU with influenza | Pre-children’s vaccine: approx 1 in 24,000 (0.004%) for under 5s (majority with underlying conditions). |
| Risk of death from influenza |
Pre-vaccine: 4 deaths in 10 years for under 5s (1978 to 1987) approx 1 in 848,000 children (0.001%) (1978 to 1987). Post-adult vaccine: 8 deaths in 10 years (2011 to 2020) approx 1 in 419,000 children (0.002%) (2011 to 2020). |
Risk from Fluenz Nasal Spray Vaccine
1 dose annually or 2 doses 4 weeks apart if first time
| Risk Category | Potential Side Effects |
|---|---|
| Less than 1 in 10,000 (0.1%) | Severe allergic reaction |
| Up to 1 in 100 (1%) | Rash, nose bleed, allergic reactions |
| Up to 1 in 10 (1% to 10%) | Fever, muscle aches, headache |
| More than 1 in 10 | Runny or stuffy nose, reduced appetite, weakness |
Some other special warnings and precautions – avoid if
- Allergic to eggs, gentamicin, gelatin, or any other ingredients in the vaccine.
- Have severe asthma, blood disorder, or weakened immune system.
- In close contact with someone with a severely weakened immune system.
- Already taking acetylsalicylic acid (a substance present in many medicines used to relieve pain and lower fever). Acetylsalicylic acid is to be avoided for 4 weeks after vaccination due to the risk of Reye’s syndrome, a very rare but serious disease that can affect the brain and liver.
Additional post-marketing events as per Flumist Literature
- Cardiac disorders – pericarditis.
- Congenital, familial, and genetic disorders – exacerbation of mitochondrial encephalomyopathy (Leigh Syndrome).
- Immune system disorders: Hypersensitivity reactions (including anaphylactic reaction, facial edema, and urticaria).
- Nervous system disorders: Guillain-Barré syndrome, Bell’s Palsy, meningitis, encephalitis, polyradiculitis, vaccine-associated encephalitis, and myelitis.
- Respiratory, thoracic, and mediastinal disorders: Epistaxis.
Adverse Events on WHO Vigibase Reporting System
As of February 2024, there were 323,599 reports for all influenza vaccines.
What is influenza?
Influenza is a viral infection that produces fever, chills, sore throat, muscle aches, and cough that lasts a week or more. People tend to use the term “flu” to describe any kind of respiratory or gastrointestinal illness, such as colds or diarrhoea and vomiting that resemble “influenza-like-illness” (ILI) symptoms. But influenza is usually associated with more severe illness and lasts longer than the common cold and, normally, influenza does not cause vomiting or diarrhoea in adults.
The vast majority of people recover from influenza without any complications and develop immunity to future infection [1] with the same strain or a related influenza strain that may prevent illness symptoms or make illness less severe. There is, however, an increased risk of serious complications and death for the elderly and those with compromised immune systems or who are suffering from diabetes, kidney, heart or neurological disease [2].
What is the risk of being admitted to ICU with influenza in Ireland?
What is the risk of death from influenza in Ireland?
The risk of death from influenza for all ages in the decade before the vaccine was introduced in 1988 was approximately 1 in 54,000 (0.002%). The majority of deaths were in people over 75 years old. The risk of dying for under 5 year olds was 1 in 848,000 (0.0001%).
In the most recent decade, after the roll of out the adult vaccine, the risk of death for all ages decreased to approximately 1 in 100,000 (0.001%) however, risk of death for under 5s, increased to approximately 1 in 419,000 (0.0002%). Most deaths were over the age of 75.
Does the influenza vaccine guarantee protection against influenza?
No. As with all vaccines and as stated on the patient information leaflets, protection from the disease cannot be guaranteed.
There are hundreds of strains of flu. The strains included in the vaccine are the ones that are predicted to be circulating at the time of formulation. In the US, effectiveness was below 40% for eight years out of the last ten.
Additional safety data
Like all medicines, vaccines come with side effects, sometimes very serious.
- See disease vs vaccine risk table at the top of this page for possible side effects from the vaccine
- Fluenz contains genetically modified organisms, long term safety of which is unknown.
- Method of delivery through nasal cavity is very close to your child’s brain.
- The live influenza vaccine, (Fluenz nasal spray) can shed causing aerosol transmission of the virus to others .
- There is a rare risk of Guillain-Barré syndrome following flu vaccination.
- Live flu vaccines such as Fluenz, can cause streptococcus in children.
- Fluenz is administered as Flumist in the US. Additional post marketing observations listed on the FDA package insert include pericarditis, congenital, familial and genetic disorders, exacerbation of mitochondrial encephalomyopathy, nervous system disorders including encephalitis and meningitis.
- As of February, 2024, there were 323,599 reports of adverse events (ADR’s) on the World Health Organisation VigiAccess database for influenza vaccines. Among these ADRs were 1,424 deaths (under general disorders), 7,371 cardiac disorders and 86,299 nervous system disorders (including 4,020 reports of Guillain Barré syndrome). Pregnancy related ADRs included 265 spontaneous abortions, 97 foetal deaths and 58 stillbirths.
- Injury and death from the Influenza vaccines are the leading types of claims submitted to the Vaccine Injury Compensation Program (VICP) in the US and account for more than half of the $5bn compensation paid out since the start of the program in 1988 .
What are the vaccine ingredients?
| Vaccine | Ingredients as listed on patient information leaflet |
|---|---|
| Fluenz (nasal flu shot) |
Active substances: Three strains of influenza virus propagated in fertilised hens’ eggs from healthy chicken flocks, produced in VERO cells by reverse genetic technology.
Other ingredients: [popup_anything id=”3109″], [popup_anything id=”3625″], [popup_anything id=”3625″], [popup_anything id=”3621″](porcine, Type A), [popup_anything id=”3622″], [popup_anything id=”3623″] and water for injections |