What Is Fluenz Tetra?
Fluenz Tetra is a live attenuated quadrivalent influenza vaccine, administered intranasally as a needle-free spray. It protects against four influenza virus strains—two A types (H1N1 and H3N2) and two B types. This broader formulation offers enhanced protection compared to traditional trivalent vaccines.MedPath+1Wikipedia
Originally approved by the European Commission on 4 December 2013, Fluenz Tetra was authorised for prophylactic use in children aged 24 months to less than 18 years throughout the EU.European Medicines Agency (EMA)MedPathFierce Pharma
Each year, the chosen viral strains are updated based on World Health Organization (WHO) recommendations, to align with anticipated circulating influenza viruses.MedPath+1Wikipedia
How It Works
The vaccine contains live but weakened viruses delivered via nasal spray. This allows the immune system to mount a response without actual infection. Its intranasal route stimulates mucosal immunity—an essential line of defense for respiratory pathogens.MedPathWikipedia+1
Notably, including both B strains in the quadrivalent version has significant advantages, particularly since influenza B has accounted for about 25% of circulating strains in Europe.Fierce PharmaEuropean Pharmaceutical Review
Efficacy & Safety
Clinical Studies
- A major pediatric study involving over 2,000 children aged 2–17 found that Fluenz Tetra induced immune responses comparable to the trivalent Fluenz, covering all four viral strains.MedPath
- Other studies (cited by MedPath) showed that Fluenz reduced flu incidence by 73–93% compared to placebo for the three included strains, with protection against any strain ranging 70–86%.MedPath
- In head-to-head comparisons with injectable inactivated vaccines, Fluenz reduced flu cases by ≈45% for included strains and ≈55% overall. Protection levels in older children (6-17 years) were similar between both delivery methods.MedPath
Side Effects & Contraindications
Common side effects (affecting >1 in 10 children) include runny or blocked nose, headache, decreased appetite, and malaise.MedPath+1
Fluenz Tetra is not suitable for:
- Those allergic to any component (including gentamicin or egg proteins),
- Children with weakened immune systems (e.g., due to HIV, cancer, or blood disorders),
- Those taking salicylates (e.g., aspirin)—due to risk of Reye syndrome.MedPathWikipedia
Regulatory & Surveillance History
- Initial Authorisation: December 2013, via centralised EMA process (Authorisation No. EMEA/H/C/002617).MedPathGOV.UK
- Safety Monitoring: For example, during the 2016–17 flu season in England, a passive enhanced safety surveillance scheme collected adverse event data in children who received Fluenz Tetra.catalogues.ema.europa.eu
Withdrawal
On 14 July 2025, the European Commission withdrew the marketing authorisation for Fluenz Tetra at the request of AstraZeneca, citing permanent commercial discontinuation of the product.European Medicines Agency (EMA)+1
Summary Table
| Category | Details |
|---|---|
| Type & Administration | Live attenuated, quadrivalent; intranasal spray (needle-free) |
| Target Population | Children aged 2–<18 years in the EU (2013–2025) |
| Efficacy | 73–93% (specific strains); ~70–86% (any strain); 45–55% vs. injected vaccine |
| Side Effects | Runny nose, headache, poor appetite, malaise |
| Contraindications | Egg allergy, immunodeficiency, salicylates |
| Authorisation Timeline | Approved: 4 Dec 2013; Withdrawn: 14 Jul 2025 |
| Reason for Withdrawal | Discontinued for commercial reasons by AstraZeneca |
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