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Fluenz Trivalent nasal spray suspension Influenza vaccine (live attenuated, nasal)

Active Ingredient:
influenza vaccine
AstraZeneca UK Limited See contact details
ATC code: 
About Medicine
{healthcare_pro_orange} This information is for use by healthcare professionals
Last updated on emc: 17 Jul 2024
1. Name of the medicinal product

Fluenz nasal spray suspension

Influenza vaccine (live attenuated, nasal)

2. Qualitative and quantitative composition

Reassortant influenza virus* (live attenuated) of the following three strains**:

A/ Victoria/4897/2022 (H1N1)pdm09 - like strain

(A/ Norway/31694/2022, MEDI 369815)


107.0± 0.5 FFU***

A/Thailand/8/2022 (H3N2) - like strain

(A/Thailand/8/2022, MEDI 370626)


107.0± 0.5 FFU***

B/ Austria/1359417/2021 - like strain

(B/ Austria/1359417/2021, MEDI 355292)


107.0± 0.5 FFU***

… … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … ....per 0.2 ml dose

* propagated in fertilised hens' eggs from healthy chicken flocks.

** produced in VERO cells by reverse genetic technology. This product contains genetically modified organisms (GMOs).

*** Fluorescent Focus Units.

This vaccine complies with the WHO recommendation (Northern Hemisphere) and EU decision for the 2024/2025 season.

The vaccine may contain residues of the following substances: egg proteins (e.g. ovalbumin) and gentamicin. The maximum amount of ovalbumin is less than 0.024 micrograms per 0.2 ml dose (0.12 micrograms per ml).

For the full list of excipients, see section 6.1.

3. Pharmaceutical form

Nasal spray, suspension

The suspension is colourless to pale yellow, clear to opalescent with a pH of approximately 7.2. Small white particles may be present.

4. Clinical particulars
4.1 Therapeutic indications

Prophylaxis of influenza in children and adolescents from 24 months to less than 18 years of age.

The use of Fluenz should be based on official recommendations.

4.2 Posology and method of administration


Children and adolescents from 24 months

0.2 ml (administered as 0.1 ml per nostril).

For children who have not previously been vaccinated against seasonal influenza, a second dose should be given after an interval of at least 4 weeks.

Fluenz should not be used in infants and toddlers below 24 months of age because of safety concerns regarding increased rates of hospitalisation and wheezing in this population (see section 4.8).

Method of administration

Immunisation must be carried out by nasal administration.

Do not inject Fluenz.

Fluenz is administered as a divided dose in both nostrils. After administering half of the dose in one nostril, administer the other half of the dose in the other nostril immediately or shortly thereafter. The patient can breathe normally while the vaccine is being administered – there is no need to actively inhale or sniff.

See section 6.6 for administration instructions.

4.3 Contraindications

• Hypersensitivity to the active substances, to any of the excipients listed in section 6.1 (e.g. gelatin), or to gentamicin (a possible trace residue).

• Severe allergic reaction (e.g. anaphylaxis) to eggs or to egg proteins (e.g. ovalbumin).

• Children and adolescents with clinical immunodeficiency due to conditions or immunosuppressive therapy such as acute and chronic leukaemias, lymphoma, symptomatic HIV infection, cellular immune deficiencies, and high-dose corticosteroids. Fluenz is not contraindicated for use in individuals with asymptomatic HIV infection; or individuals who are receiving topical/inhaled corticosteroids or low-dose systemic corticosteroids or those receiving corticosteroids as replacement therapy, e.g. for adrenal insufficiency.

• Children and adolescents younger than 18 years of age receiving salicylate therapy because of the association of Reye's syndrome with salicylates and wild-type influenza infection.

4.4 Special warnings and precautions for use


In order to improve the traceability of biological medicinal products, the name and the batch number of the administered product should be clearly recorded.

As with most vaccines, appropriate medical treatment and supervision should always be readily available to manage an anaphylactic event or serious hypersensitivity event following the administration of Fluenz.

Fluenz should not be administered to children and adolescents with severe asthma or active wheezing because these individuals have not been adequately studied in clinical studies.

Vaccine recipients should be informed that Fluenz is an attenuated live virus vaccine and has the potential for transmission to immunocompromised contacts. Vaccine recipients should attempt to avoid, whenever possible, close association with severely immunocompromised individuals (e.g. bone marrow transplant recipients requiring isolation) for 1-2 weeks following vaccination. Peak incidence of vaccine virus recovery occurred 2-3 days post-vaccination in clinical studies. In circumstances where contact with severely immunocompromised individuals is unavoidable, the potential risk of transmission of the influenza vaccine virus should be weighed against the risk of acquiring and transmitting wild-type influenza virus.

Fluenz should, under no circumstances, be injected.

No data exist regarding the safety of intranasal administration of Fluenz in children with unrepaired craniofacial malformations.

4.5 Interaction with other medicinal products and other forms of interaction

Do not administer Fluenz to children and adolescents receiving salicylate therapy (see section 4.3). Do not use salicylates in children and adolescents for 4 weeks after vaccination unless medically indicated as Reye's syndrome has been reported following the use of salicylates during wild-type influenza infection.

The co-administration of Fluenz with the live attenuated vaccines: measles, mumps, rubella, varicella, and orally-administered poliovirus has been studied. No clinically meaningful changes in immune responses to measles, mumps, varicella, orally-administered poliovirus or Fluenz have been observed. The immune response to rubella vaccine was significantly altered. However, this alteration might not be of clinical relevance with the two dose immunisation schedule of the rubella vaccine.

The co-administration of Fluenz with inactivated vaccines has not been studied.

The concurrent use of Fluenz with antiviral agents that are active against influenza A and/or B viruses has not been evaluated. However, based upon the potential for influenza antiviral agents to reduce the effectiveness of Fluenz, it is recommended not to administer the vaccine until 48 hours after the cessation of influenza antiviral therapy. Administration of influenza antiviral agents within two weeks of vaccination may affect the response of the vaccine.

If influenza antiviral agents and Fluenz are administered concomitantly, revaccination should be considered based on clinical judgement.

4.6 Fertility, pregnancy and lactation


There is a moderate amount of data from the use of Fluenz in pregnant women. There was no evidence of significant maternal adverse outcomes in 138 pregnant women who had a record of receiving Fluenz in a US-based health insurance claims database.

In more than 300 case reports in the AstraZeneca safety database of vaccine administration to pregnant women, no unusual patterns of pregnancy complications or foetal outcomes were observed.

While animal studies do not indicate direct or indirect harmful effects with respect to reproductive toxicity, and post-marketing data offer some reassurance in the event of inadvertent administration of the vaccine, Fluenz is not recommended during pregnancy.


Limited available evidence suggests that Fluenz is not excreted in breastmilk. However, because there are limited data to assess the effects on the breast-fed infant and, as some viruses are excreted in human milk, Fluenz should not be used during breast-feeding.


No data exist regarding the possible effects of Fluenz on male and female fertility.

4.7 Effects on ability to drive and use machines

Fluenz has no or negligible influence on the ability to drive and use machines.

4.8 Undesirable effects

Summary of the safety profile

Safety data regarding use of Fluenz are based on data from Fluenz clinical studies in over 29,000 children and adolescents 2 to 17 years of age, Fluenz post-authorisation safety studies in over 84,000 children and adolescents 2 to 17 years of age, and data from Fluenz Tetra (influenza vaccine-live attenuated, nasal) clinical studies in over 2,000 children and adolescents 2 to 17 years of age. Additional experience has occurred with marketed use of Fluenz and Fluenz Tetra.

In clinical studies, the safety profile of Fluenz and Fluenz Tetra were similar.

The most common adverse reaction observed in clinical studies was nasal congestion/rhinorrhoea.

List of adverse reactions

Adverse reaction frequencies are reported as:

Very common (≥ 1/10)

Common (≥ 1/100 to <1/10)

Uncommon (≥ 1/1,000 to <1/100)

Rare (≥ 1/10,000 to <1/1,000)

Very rare (<1/10,000)

Immune system disorders

Uncommon: Hypersensitivity reactions (including facial oedema, urticaria and very rare anaphylactic reactions)

Metabolism and nutrition disorders

Very common: Decreased appetite

Nervous system disorders

Common: Headache

Respiratory, thoracic and mediastinal disorders

Very common: Nasal congestion/rhinorrhoea

Uncommon: Epistaxis

Skin and subcutaneous tissue disorders

Uncommon: Rash

Musculoskeletal and connective tissue disorders

Common: Myalgia

General disorders and administration site conditions

Very common: Malaise

Common: Pyrexia

Paediatric population

In an active-controlled clinical study (MI-CP111), an increased rate of hospitalisations (for any cause) through 180 days after final vaccination dose was observed in infants and toddlers 6-11 months of age (6.1% Fluenz versus 2.6% injectable influenza vaccine). Most hospitalisations were due to gastrointestinal and respiratory tract infections and occurred more than 6 weeks post vaccination. The rate of hospitalisations was not increased in Fluenz recipients 12 months and older. In the same study, an increased rate of wheezing through 42 days was observed in infants and toddlers 6-23 months of age (5.9% Fluenz versus 3.8% injectable influenza vaccine). The rate of wheezing was not increased in Fluenz recipients 24 months and older. Fluenz is not indicated for use in infants and toddlers younger than 24 months (see section 4.2).

Very rare reports of Guillain-Barré syndrome and exacerbation of symptoms of Leigh syndrome (mitochondrial encephalomyopathy) have also been observed in the post-marketing setting with Fluenz.

Reporting of suspected adverse reactions

Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via the Yellow Card Scheme at or search for MHRA Yellow Card in the Google Play or Apple App Store.

4.9 Overdose

Overdose with Fluenz is unlikely due to its presentation as a pre-filled sprayer. Administration of a higher than recommended dose of Fluenz was reported rarely and the adverse reaction profile was comparable to that observed with the recommended dose of Fluenz.

5. Pharmacological properties
5.1 Pharmacodynamic properties

Pharmacotherapeutic group: Influenza vaccines, influenza live attenuated; ATC Code: J07BB03

Fluenz is a trivalent vaccine that contains antigens for three influenza virus strains, an A/(H1N1) strain, an A/(H3N2) strain, and a B strain from the Victoria lineage. The influenza virus strains in Fluenz are (a) cold-adapted (ca); (b) temperature-sensitive (ts); and (c) attenuated (att). As a result, they replicate in the nasopharynx and induce protective immunity.

Clinical efficacy and safety

Clinical efficacy

Fluenz's efficacy data in the paediatric population consist of 9 controlled studies comprising over 20,000 infants and toddlers, children and adolescents, conducted during 7 influenza seasons. Four placebo-controlled studies included second season revaccination. Fluenz has demonstrated superiority in 3 active-controlled studies with injectable influenza vaccine. See Table 1 and 2 for a summary of efficacy results in the paediatric population.

Table 1 Fluenz Efficacy in Placebo Controlled Paediatric Studies

Study Number


Age Rangea

Number of Study Participantsb

Influenza Season


(95% CI)c

Matched strains


(95% CI)c

All strains regardless of match



6 to 35 M




(74.3, 92.2)


(76.3, 92.0)



(82.0, 93.2)


(78.6, 90.9)


Africa, Latin America

6 to 35 M




(63.6, 81.0)d


(61.9, 79.8)d



(33.3, 91.2)


(14.9, 67.2)


Asia/ Oceania

6 to 35 M




(43.6, 75.2)


(28.8, 63.3)


Europe, Asia/ Oceania, Latin America

11 to 24 M




(50.9, 91.3)


(36.2, 79.8)


Asia/ Oceania

12 to 35 M




(62.8, 80.5)


(60.9, 77.3)



(70.1, 92.4)e


(44.2, 77.3)e



15 to 71 M




(87.5, 96.5)


(87.5, 96.5)



(63.1, 100)


(77.7, 92.6)f

a M=months.

b Number of study participants for year 1 efficacy analysis.

c Reduction in culture-confirmed influenza illness relative to placebo.

d Data presented for clinical trial D153-P504 are for study participants who received two doses of study vaccine. In previously unvaccinated study participants who received one dose in year 1, efficacy was 57.7% (95% CI: 44.7, 67.9) and 56.3% (95% CI: 43.1, 66.7), respectively, thus supporting the need for two doses of vaccine in previously unvaccinated children.

e In study participants who received 2 doses in year 1 and placebo in year 2, efficacy in year 2 was 56.2% (95% CI: 30.5, 72.7) and 44.8% (95% CI: 18.2, 62.9), respectively, in D153-P501, thus supporting the need for second-season revaccination.

f The primary circulating strain was antigenically dissimilar from the H3N2 strain represented in the vaccine; efficacy against the mismatched A/H3N2 strain was 85.9% (95% CI: 75.3, 91.9).

Table 2 Fluenz Relative Efficacy in Active-controlled Paediatric Studies with Injectable Influenza Vaccine

Study Number


Age Rangea

Number of Study Participants

Influenza Season

Improved Efficacy

(95% CI)b

Matched strains

Improved Efficacy

(95% CI)b

All strains regardless of match


USA, Europe, Asia/Oceania

6 to 59 M




(22.4, 60.6)

fewer cases than injectable


(45.4, 62.9)c

fewer cases than injectable



6 to 71 M




(21.6, 72.2)

fewer cases than injectable


(24.6, 70.5)d

fewer cases than injectable



6 to 17 Y




(3.9, 56.0)

fewer cases than injectable


(1.1, 53.5)

fewer cases than injectable

a M=months. Y=years. Age range as described in the protocol for the study.

b Reduction in culture-confirmed influenza illness relative to injectable influenza vaccine.

c Fluenz demonstrated 55.7% (39.9, 67.6) fewer cases than injectable influenza vaccine in 3,686 infants and toddlers 6-23 months of age and 54.4% (41.8, 64.5) fewer cases in 4,166 children 24-59 months of age.

d Fluenz demonstrated 64.4% (1.4, 88.8) fewer cases than injectable influenza vaccine in 476 infants and toddlers 6-23 months of age and 48.2% (12.7, 70.0) fewer cases in 1,609 children 24-71 months of age.

Clinical safety

Chronic conditions

Although safety in children and adolescents with mild to moderate asthma has been established, data in children with other pulmonary diseases or with chronic cardiovascular, metabolic or renal diseases are limited.

In a study (D153-P515) of children 6 to 17 years of age with asthma (Fluenz: n=1,114, trivalent injectable influenza vaccine: n=1,115), there were no significant differences between treatment groups in the incidence of asthma exacerbations, mean peak expiratory flow rate, asthma symptom scores, or night-time awakening scores. The incidence of wheezing within 15 days after vaccination was lower in Fluenz recipients relative to inactivated vaccine recipients (19.5% vs. 23.8%, P=0.02).

In a study of children and adolescents 9 to 17 years of age with moderate to severe asthma (Fluenz: n=24, placebo: n=24), the primary safety criterion, change in percent predicted forced expiratory volume in 1 second (FEV1) measured before and after vaccination, did not differ between treatment arms.

In studies of adults in which a high percentage of individuals had underlying chronic medical conditions, the safety profile of Fluenz was comparable to the safety profile observed in individuals without these conditions.


In 24 HIV-infected children and 25 HIV-negative children 1 through 7 years of age, and in 243 HIV-infected children and adolescents 5 through 17 years of age receiving stable anti-retroviral therapy, the frequency and duration of vaccine virus shedding were comparable to that seen in healthy individuals. No adverse effects on HIV viral load or CD4 counts were identified following Fluenz administration. Twenty mild to moderately immunocompromised children and adolescents 5 through 17 years of age (receiving chemotherapy and/or radiation therapy or who had recently received chemotherapy) were randomised 1:1 to Fluenz or placebo. Frequency and duration of vaccine virus shedding in these immunocompromised children and adolescents were comparable to that seen in healthy children and adolescents. The effectiveness of Fluenz preventing influenza illness in immunocompromised individuals has not been evaluated.

Adult studies

Several studies against placebo have shown that Fluenz may have some efficacy in adults. However, a conclusion on clinical benefit of this vaccine in adults could not be made given that results observed in some studies versus injectable influenza vaccines were suggestive of a lower efficacy of Fluenz.

5.2 Pharmacokinetic properties

Not applicable.

5.3 Preclinical safety data

Non-clinical data reveal no special hazard for humans based on conventional non-clinical studies of repeated dose toxicity, reproduction and developmental toxicity, local tolerance and neurovirulence.

6. Pharmaceutical particulars
6.1 List of excipients


Dipotassium phosphate

Potassium dihydrogen phosphate

Gelatin (porcine, Type A)

Arginine hydrochloride

Monosodium glutamate monohydrate

Water for injections

6.2 Incompatibilities

In the absence of compatibility studies, this vaccine must not be mixed with other medicinal products.

6.3 Shelf life

15 weeks.

6.4 Special precautions for storage

Store in a refrigerator (2° C – 8° C).

Do not freeze.

Keep the nasal applicator in the outer carton in order to protect from light.

Before use, the vaccine may be taken out of the refrigerator once for a maximum period of 12 hours at a temperature not above 25° C. Stability data indicate that the vaccine components are stable for 12 hours when stored at temperatures from 8° C to 25° C. At the end of this period, Fluenz should be used immediately or discarded.

6.5 Nature and contents of container

Fluenz is supplied as a 0.2 ml suspension in a single-use nasal applicator (Type 1 glass), with nozzle (polypropylene with polyethylene transfer valve), nozzle tip-protector cap (synthetic rubber), plunger rod, plunger-stopper (butyl rubber) and a dose-divider clip.

Pack size of 1 or 10.

Not all pack sizes may be marketed.

6.6 Special precautions for disposal and other handling



• DO NOT USE WITH A NEEDLE. Do not inject.


• Do not use Fluenz if the expiry date has passed or the sprayer appears damaged, for example, if the plunger is loose or displaced from the sprayer or if there are any signs of leakage.

• Check the appearance of the vaccine before administration. The suspension should be colourless to pale yellow, clear to opalescent. Small white particles may be present.

• Fluenz is administered as a divided dose in both nostrils.

• After administering half of the dose in one nostril, administer the other half of the dose in the other nostril immediately or shortly thereafter.

• The patient can breathe normally while the vaccine is being administered – there is no need to actively inhale or sniff.

• Refer to the Fluenz administration diagram (Figure 1) for step-by-step administration instructions.

Figure 1: Fluenz Administration



Any unused medicinal product or waste material should be disposed of in accordance with local requirements for medical waste.

7. Marketing authorisation holder

AstraZeneca UK Limited,

1 Francis Crick Avenue,


CB2 0AA,


8. Marketing authorisation number(s)

PLGB 17901/0378

9. Date of first authorisation/renewal of the authorisation

Date of first authorisation: 26 June 2024

10. Date of revision of the text

16 July 2024

AstraZeneca UK Limited
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