Risk from Influenza for Children Under 5
Category Details
Risk of admission to ICU with influenza approx 1 in 44,000 (0.002%);(Over 85% with pre-existing condition)
during pregnancy; approx 1 in 28,000 pregnancies (0.004%)
under 5s approx 1 in 24,000 (0.004%)
Risk of death from influenza approx 1 in 100,000 (0.001%);
under 5s : approx 1 in 419,000 (0.0002%)
There is no record of any deaths for pregnant women from influenza during this period

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 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 .

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.

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 vaccines are recommended on the pregnancy/childhood schedule for influenza in Ireland?

Since 2011 , the HSE recommend pregnant women be vaccinated against influenza during the flu season, October through April. Before 2011, there were no vaccines recommended during pregnancy. There are two inactivated vaccines available:

  • Influvac Tetra manufactured Abbot Biologicals
  • Quadrivalent manufactured by Sanofi

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).

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.