Vaccination fatigue: Is Europe facing a severe flu epidemic this year?

Some pediatricians have warned that the unfolding flu season could hit Europe particularly hard this winter, with younger patients having a particularly hard time.

Why influenza strikes the youngest so hard

Influenza is extremely common in children worldwide. Young children in particular have an increased risk of a severe course of the disease. The clinical manifestation of influenza in children is wide-ranging. Secondary diseases of influenza, such as sinusitis, acute otitis media, and secondary bacterial pneumonia, are particularly troublesome for this young population group. In addition, because children have not yet fully learnt hygiene measures during an infection, they are often carriers and can infect those around them. There is ample evidence of the crucial role of children in the spread of influenza. But the current vaccination fatigue can have serious consequences not only for the young, but for us all.2

Rapidly rising numbers in Australia are a sign of a severe flu epidemic

The northern hemisphere sommer was winter time in Australia. As a result, the Australian population is affected by the flu epidemic a good six months before Europe. The flu epidemic in Australia hit children particularly hard this year: There have already been two flu-related deaths in the southern hemisphere. Children's immune systems could not be sufficiently prepared due to the isolation measures during the COVID-19 pandemic. During the lockdown phase, the hygiene measures had contributed to fewer cases of influenza. The removal of these isolation measures in combination with children's untrained immune systems led to an increased incidence of influenza cases in children under the age of 14 in Australia this year. This was exacerbated by a decline in immunisation rates in this young population group.1

Influenza A dominated Australia's flu epidemic

According to the National Notifiable Diseases Surveillance System (NNDSS), influenza A is responsible for 65% of laboratory-confirmed influenza cases. Of these, 95% were influenza A (unsubtyped), 5% influenza A(H1N1) and 1% influenza A(H3N2). Influenza B viruses accounted for 32.7 % of laboratory-confirmed influenza cases this year.2

The influenza wave in Europe: learning from Australia's mistakes

The viruses currently prevalent in Australia are influenza A (H1N1) and influenza B. These variants mostly affect children. Another problem that Australia had to contend with was some degree of vaccination fatigue. Only a third of the population was vaccinated against influenza. The lowest immunisation rates were observed in children between the ages of 5 and 14. Only around 12% of children in this age group had been vaccinated against influenza this year. In 2020, the vaccination rate was still 25%. For children aged 6 months to 5 years, the vaccination rate in 2020 was still 40%.

This year, only 20% of children in this age group received a flu vaccination. This declining vaccination rate has not been without consequences. Around 80% of patients hospitalised for flu in Australia were children aged 6 months to 5 years.1-6

There is still time to implement flu immunisation in Europe for this young population group to avoid Australia's mistakes.

References
  1. [In German only] https://www.rnd.de/gesundheit/grippe-2023-kinderaerzte-praesident-warnt-vor-influenza-welle-im-kommenden-winter-QQRWMSKYNNNBVKIHX5YGSBVZFU.html
  2. Hoy G. et al. (2023). The Spectrum of Influenza in Children. Clin Infect Dis. 2023 Feb 8;76(3):e1012-e1020. 
  3. https://www.health.gov.au/sites/default/files/2023-07/aisr-fortnightly-report-no-7-26-june-to-09-july-2023.pdf
  4. [In German only] https://www.morgenpost.de/ratgeber/article239087345/australien-grippewelle-grippe-kinder-europa-warnung.html
  5. https://cdn.who.int/media/docs/default-source/wpro---documents/emergency/surveillance/seasonal-influenza/influenza-20230802.pdf?sfvrsn=39dcc97a_110
  6. https://www.theguardian.com/australia-news/2023/jun/26/australia-2023-flu-season-kids-kindy-influenza-children