Pharmacy Guide
Patient leaflets and SmPCs, drug interaction checker, official dosages and NHS pharmacy opening hours — all in one place.
Pharmacy Guide
Patient leaflets and SmPCs, drug interaction checker, official dosages and NHS pharmacy opening hours — all in one place.
Adjuvanted Trivalent Influenza Vaccine (Surface Antigen, Inactivated) Seqirus suspension for injection in pre-filled syringe
⚠ This medicine appears to have been discontinued
The electronic medicines compendium (emc) no longer publishes a Summary of Product Characteristics for this product, which usually means it is no longer marketed in the UK. The patient leaflet below is kept for reference, but the product may not be available.
If you were prescribed this medicine, other products containing Influenza vaccine (surface antigen, inactivated) may still be available. Do not stop your treatment — ask your pharmacist or GP what to use instead.
What it is and what it is used for
for
Adjuvanted Trivalent Influenza Vaccine Seqirus is a vaccine against flu (influenza). When a person is given the vaccine, the immune system (the body's natural defence system) will produce its own protection against the influenza virus. None of the ingredients in the vaccine can cause flu. This vaccine is used to prevent flu in adults of 50 years of age and older. This vaccine targets three strains of influenza virus following the recommendations by the World Health Organisation for the 2025/2026 season. 2.
What you need to know before you take it
e Adjuvanted Trivalent Influenza Vaccine Seqirus You should not receive Adjuvanted Trivalent Influenza Vaccine Seqirus –
If you are allergic to the active ingredients or any of the other ingredients of this medicine (listed in section 6) egg or chicken proteins (such as ovalbumin), kanamycin and neomycin sulphate, formaldehyde, cetyltrimethylammonium bromide (CTAB) and hydrocortisone, which are trace residues from the manufacturing process.
- If you have had a severe allergic reaction (e.g. anaphylaxis) to previous influenza vaccination.
7
Warnings and precautions Talk to your doctor, pharmacist or nurse before receiving Adjuvanted Trivalent Influenza Vaccine Seqirus. BEFORE receiving the vaccine Your doctor or nurse will make sure that appropriate medical treatment and supervision is readily available in case of a rare anaphylactic reaction (a very severe allergic reaction with symptoms such as difficulty in breathing, dizziness, a weak and rapid pulse and skin rash) following the administration. This reaction may occur with Adjuvanted Trivalent Influenza Vaccine Seqirus as with all vaccines that are injected. You should tell your doctor if you have an illness associated with fever. Your doctor may decide to delay your vaccination until your fever is gone. You should tell your doctor if your immune system is impaired, or if you are undergoing treatment which affects the immune system, e.g. with medicine against cancer (chemotherapy) or corticosteroid medicines (see Section "Other medicines and Adjuvanted Trivalent Influenza Vaccine Seqirus"). You should tell your doctor if you have a bleeding problem or bruise easily. Fainting can occur following, or even before, any needle injection, therefore tell the doctor or nurse if you fainted with a previous injection. As with all vaccines, Adjuvanted Trivalent Influenza Vaccine Seqirus may not fully protect all persons who are vaccinated. Children Adjuvanted Trivalent Influenza Vaccine Seqirus is not recommended for use in children. Other medicines and Adjuvanted Trivalent Influenza Vaccine Seqirus Tell your doctor or nurse if you are using, have recently used or might use any other medicines, including medicines obtained without a prescription or if you have recently received any other vaccine. Pregnancy and breast-feeding This vaccine is for use in adults 50 years and older. It is not to be used in women who are, or may be, pregnant or breast-feeding. Driving and using machines This vaccine has no or negligible influence on the ability to drive and use machines. Adjuvanted Trivalent Influenza Vaccine Seqirus contains potassium and sodium This vaccine contains less than 1 mmol sodium (23 mg) per dose, i.e. essentially 'sodium free'. This vaccine contains potassium, less than 1 mmol (39 mg) per dose, i.e. essentially 'potassium free'. 3.
How to take it
Adjuvanted Trivalent Influenza Vaccine Seqirus is given by your doctor or nurse as an injection into the muscle at the top of the upper arm (deltoid muscle). Adults of 50 years of age and older: One dose of 0.5 ml 4.
Possible side effects
Like all medicines, this medicine can cause side effects, although not everybody gets them. 8
Tell your doctor immediately or go to the casualty department at your nearest hospital if you experience the following serious side effect – you may need urgent medical attention or hospitalisation:
- Difficulty in breathing, dizziness, a weak and rapid pulse and skin rash which are symptoms of an anaphylactic reaction (a very severe allergic reaction) The following side effects have been reported during clinical trials in adults 50 years of age and older. Very common (may affect more than 1 in 10 people):
- Pain at injection site
- Fatigue
- Headache
- Joint pain (arthralgia)
- Muscular pain (myalgia) Common (may affect up to 1 in 10 people):
- Redness at injection site (erythema)
- Hardening of the skin at injection site (induration)
- Bruising at injection site (ecchymosis)
- Diarrhoea
- Nausea
- Loss of appetite
- Fever (≥ 38°C)
- Shivering
- Flu-like symptoms (only reported in individuals 65 years of age and older)
Uncommon (may affect up to 1 in 100 people):
- Vomiting
- Swelling of the glands in the neck, armpit or groin (lymphadenopathy) In individuals 65 years of age and older, some side effects were less frequent, such as arthralgia, myalgia (common) and fever (uncommon). Most side effects were mild or moderate and went away within 3 days of appearing. In addition, the following side effects occurred occasionally during general use of this vaccine or a similar vaccine in elderly individuals 65 years of age and older:
- Reduction in the number of certain types of particles in the blood called platelets; a low number of these can result in excessive bruising or bleeding (thrombocytopenia)
- Swelling, pain and redness at the injection site (injection site cellulitis-like reaction)
- Extensive swelling of injected limb
- Swelling of the lower legs or hands (peripheral swelling)
- General weakness or lack of energy (asthenia), generally feeling unwell (malaise)
- Muscular weakness
- Pain on the nerve path (neuralgia), unusual feeling of touch, pain, heat and cold (paraesthesia), fits (convulsions), neurological disorders that may result in stiff neck, confusion, numbness, pain and weakness of the limbs, loss of balance, loss of reflexes, paralysis of part or all the body (encephalomyelitis, neuritis, Guillain-Barré Syndrome) Skin reactions that may spread throughout the body including itchiness of the skin (pruritus, urticaria), skin redness (erythema), non-specific rash
- Severe skin rash (erythema multiforme)
9
• • • •
Swelling most apparent in the head and neck, including the face, lips, tongue, throat or any other part of the body (angioedema) Blood vessel swelling that may cause skin rashes (vasculitis) and temporary kidney problems Dizziness Fainting, feeling about to faint (syncope, presyncope)
Reporting of side effects If you get any side effects, talk to your doctor, pharmacist or nurse. This includes any possible side effects not listed in this leaflet. You can also report side effects directly via the Yellow Card Scheme website: www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store. By reporting side effects you can help provide more information on the safety of this medicine. 5.
How to store it
Adjuvanted Trivalent Influenza Vaccine Seqirus
Keep this medicine out of the sight and reach of children. Store in a refrigerator (2 °C to 8 °C). Do not freeze. Discard if the vaccine has been frozen. Keep the pre-filled syringe in the outer carton in order to protect from light. Do not use this medicine after the expiry date which is stated on the label and carton after EXP. The expiry date refers to the last day of that month. Do not throw away any medicines via wastewater or household waste. Ask your pharmacist how to throw away medicines you no longer use. These measures will help protect the environment. 6.
Contents of the pack and other information
What Adjuvanted Trivalent Influenza Vaccine Seqirus contains –
The active substances are influenza virus surface antigens (haemagglutinin and neuraminidase), inactivated, of the following strains*: per 0.5 ml dose A/Victoria/4897/2022 (H1N1)pdm09-like strain
(A/Victoria/4897/2022, IVR-238)
15 micrograms HA**
A/Croatia/10136RV/2023 (H3N2)-like strain (A/Croatia/10136RV/2023, X-425A)
15 micrograms HA**
B/Austria/1359417/2021-like strain (B/Austria/1359417/2021, BVR-26)
15 micrograms HA**
*propagated in fertilised hens' eggs from healthy chicken flocks and adjuvanted with MF59C.1 **haemagglutinin
This vaccine complies with the WHO recommendations (Northern Hemisphere) and EU recommendation for the 2025/2026 season. –
MF59C.1 is included in this vaccine as an adjuvant. Adjuvants are substances included in certain vaccines to accelerate, improve and/or prolong the protective effects of the vaccine. MF59C.1 is an adjuvant that contains per 0.5 ml dose: squalene (9.75 mg), polysorbate 80 (1.175 mg), sorbitan trioleate (1.175 mg), sodium citrate (0.66 mg) and citric acid (0.04 mg).
10
–
The other ingredients are: sodium chloride, potassium chloride, potassium dihydrogen phosphate, disodium phosphate dihydrate, magnesium chloride hexahydrate, calcium chloride dihydrate and water for injections.
What Adjuvanted Trivalent Influenza Vaccine Seqirus looks like and contents of the pack Adjuvanted Trivalent Influenza Vaccine Seqirus is a suspension for injection in a pre-filled syringe. It is a milky-white suspension. A single syringe contains 0.5 ml of suspension for injection. Adjuvanted Trivalent Influenza Vaccine Seqirus is available in packs containing 1 or 10 pre-filled syringes with or without needles. Not all pack sizes may be marketed. Marketing Authorisation Holder Seqirus UK Ltd. Point, 29 Market Street Maidenhead SL6 8AA, United Kingdom Manufacturer Seqirus Vaccines Limited Gaskill Road, Speke L24 9GR Liverpool United Kingdom This leaflet was last revised in 06/2025. ———————————————————————————————————————–The following information is intended for healthcare professionals only: Appropriate medical treatment and supervision should always be readily available in case of a rare anaphylactic event following the administration of the vaccine. Gently shake before use. After shaking, the normal appearance of the vaccine is a milky white suspension. The vaccine should be visually inspected for particulate matter and discoloration prior to administration. In the event of any foreign particulate matter and/or variation of physical aspect being observed, do not administer the vaccine. When using a pre-filled syringe supplied without a needle, remove the tip cap from the syringe and then attach a suitable needle for administration. For Luer Lock syringes, remove the tip cap by unscrewing it in a counter-clockwise direction. Once the tip cap is removed, attach a needle to the syringe by screwing it on in a clockwise direction until it locks. Once the needle is locked in place, remove the needle protector and administer the vaccine.
11
Frequently asked questions about Adjuvanted Trivalent Influenza Vaccine (Surface Antigen, Inactivated) Seqirus suspension for injection in pre-filled syringe
How do I take Adjuvanted Trivalent Influenza Vaccine (Surface Antigen, Inactivated) Seqirus suspension for injection in pre-filled syringe?
Adjuvanted Trivalent Influenza Vaccine (Surface Antigen, Inactivated) Seqirus suspension for injection in pre-filled syringe comes as oral solution. Always follow the dose your doctor or pharmacist has given you, and read the leaflet that comes with the medicine.
What is the active substance in Adjuvanted Trivalent Influenza Vaccine (Surface Antigen, Inactivated) Seqirus suspension for injection in pre-filled syringe?
The active substance in Adjuvanted Trivalent Influenza Vaccine (Surface Antigen, Inactivated) Seqirus suspension for injection in pre-filled syringe is influenza vaccine (surface antigen, inactivated).
Are there equivalent medicines to Adjuvanted Trivalent Influenza Vaccine (Surface Antigen, Inactivated) Seqirus suspension for injection in pre-filled syringe?
Medicines with the same active substance, strength and form include: Adjuvanted Quadrivalent Influenza Vaccine (Surface Antigen, Inactivated) Seqirus suspension for injection in pre-filled syringe Influenza vaccine, Adjuvanted with MF59C.1, Adjuvanted Zoonotic Influenza Vaccine (Surface Antigen, Inactivated) Seqirus suspension for injection in pre‐filled syringe, Cell-based Quadrivalent Influenza Vaccine (Surface Antigen, Inactivated) Seqirus suspension for injection in pre-filled syringe. In total there are 4 equivalent products. They are interchangeable only if your prescriber or pharmacist says so.
Where does this information come from?
This leaflet reproduces the patient information leaflet approved for Adjuvanted Trivalent Influenza Vaccine (Surface Antigen, Inactivated) Seqirus suspension for injection in pre-filled syringe, as published on the electronic medicines compendium (emc). The version printed inside your medicine’s packaging is the one that applies to you.
Can I get Adjuvanted Trivalent Influenza Vaccine (Surface Antigen, Inactivated) Seqirus suspension for injection in pre-filled syringe without a prescription?
Whether a medicine is available over the counter or on prescription only depends on its licence. Check the leaflet, or ask your pharmacist — they can tell you straight away.
About this leaflet
The text above reproduces the patient information leaflet approved for this medicine, restructured for easier reading.
- Source: electronic medicines compendium (emc), Datapharm
- Active substance: influenza vaccine (surface antigen, inactivated)
- Official document: view the original leaflet on emc →
⚕For healthcare professionals — Summary of Product Characteristics (SmPC)Full SmPC: dosage, interactions, contraindications, warnings+
4.1. Therapeutic indications
Prophylaxis of influenza in adults 50 years of age and older.
Adjuvanted Trivalent Influenza Vaccine Seqirus should be used in accordance with official recommendations.
4.2. Posology and method of administration
Posology
One 0.5 ml dose.
Paediatric population
The safety and efficacy of Adjuvanted Trivalent Influenza Vaccine Seqirus in children from birth to less than 18 years has not been established. Currently available safety and immunogenicity data in children from 6 months to less than 6 years of age are described in sections 4.8 and 5.1 but no recommendation on posology can be made.
Method of administration
For intramuscular injection only.
The preferred injection site is the deltoid muscle of the upper arm.
The vaccine must not be injected intravenously, subcutaneously or intradermally and must not be mixed with other vaccines in the same syringe.
For instructions for preparation of the medicinal product before administration, see section 6.6.
4.3. Contraindications
Hypersensitivity to the active substances, to any of the components of the adjuvant, to any of the excipients listed in section 6.1, or to possible trace residues such as ovalbumin, kanamycin and neomycin sulphate, formaldehyde, cetyltrimethylammonium bromide (CTAB) and hydrocortisone.
A severe allergic reaction (e.g. anaphylaxis) to previous influenza vaccination.
4.4. Special warnings and precautions for use
Traceability
In order to improve the traceability of biological medicinal products, the name and the batch number of the administered product should be clearly recorded.
Appropriate medical treatment and supervision should always be readily available in case of an anaphylactic event following the administration of the vaccine.
Vaccination should be postponed in patients with febrile illness until the fever is resolved.
As with all injectable vaccines, Adjuvanted Trivalent Influenza Vaccine Seqirus must be administered with caution to individuals with thrombocytopenia or a bleeding disorder since bleeding may occur following an intramuscular administration.
Syncope (fainting) can occur following, or even before, any vaccination as a psychogenic response to the needle injection. This can be accompanied by several neurological signs such as transient visual disturbance, paraesthesia and tonic-clonic limb movements during recovery. It is important that procedures are in place to avoid injury from faints.
Antibody response in patients with endogenous or iatrogenic immunosuppression may be insufficient to prevent influenza.
A protective immune response may not be elicited in all vaccine recipients.
Excipients with known effect
Sodium
This vaccine contains less than 1 mmol sodium (23 mg) per dose, that is to say essentially 'sodium-free'.
Potassium
This vaccine contains potassium, less than 1 mmol (39 mg) per dose, that is to say essentially 'potassium-free'.
4.5. Interaction with other medicinal products and other forms of interaction
Concomitant administration of Adjuvanted Trivalent Influenza Vaccine Seqirus with other vaccines has not been studied in trials conducted by Seqirus. However, data supports co-administration with COVID vaccines showing the antibody responses are unaffected and the reactogenicity profile is acceptable. If it is to be used at the same time as another vaccine, it should be administered at separate injection sites and preferably on different limbs. It should be noted that the adverse reactions may be intensified.
4.6. Fertility, pregnancy and lactation
Women of childbearing potential
This medicine is not indicated in women of childbearing potential (see section 4.1). It is not to be used in women who are, or may be, pregnant or breast-feeding.
Pregnancy
There are no data from the use of Adjuvanted Trivalent Influenza Vaccine Seqirus in pregnant women. Animal studies do not indicate direct or indirect harmful effects with respect to reproductive toxicity.
4.7. Effects on ability to drive and use machines
Adjuvanted Trivalent Influenza Vaccine Seqirus has no or negligible influence on the ability to drive and use machines.
4.8. Undesirable effects
Summary of the safety profile
Adults 50 years of age and older
Data for Adjuvanted Quadrivalent Influenza Vaccine Seqirus are relevant to Adjuvanted Trivalent Influenza Vaccine Seqirus because both vaccines are manufactured using the same process and have overlapping compositions.
Safety was evaluated in three clinical studies in which 1027 adults 50 to less than 65 years of age (Study V118_23) and 4269 elderly subjects 65 years of age and older (Studies V118_20 and V118_18) received Adjuvanted Quadrivalent Influenza Vaccine Seqirus or one of two formulations of an adjuvanted trivalent comparator (N=888). Similar rates of solicited local and systemic adverse reactions were reported in subjects who received the quadrivalent and trivalent formulations.
Commonly reported (≥10%) adverse reactions in adults 50 to less than 65 years of age were injection site pain (47%), fatigue (29%), headache (22%), arthralgia (14%) and myalgia (13%) (V118_23).
Commonly reported (≥10%) adverse reactions in elderly subjects 65 years of age and older were injection site pain (16% and 32%), fatigue (10% and 16%) and headache (11% and 12%) for V118_18 and V118_20, respectively. Most solicited reactions were reported as mild or moderate in intensity and resolved within the first 3 days after vaccination.
Paediatric population
Adjuvanted Trivalent Influenza Vaccine Seqirus is not indicated for use in children, see section 4.2. Safety information in the paediatric population is presented in section 5.1.
Tabulated list of adverse reactions
Adverse reactions reported are listed according to the following frequency categories: Very common (≥1/10); Common (≥1/100 - <1/10); Uncommon (≥1/1,000 - <1/100). Frequency not known
Table 1: Adverse reactions reported following vaccination in adults subjects 50 years and older in clinical trials and post-marketing surveillance
MedDRA System Organ class
Very common
(≥1/10)
Common
(1/100 to <1/10)
Uncommon
(1/1,000 to<1/100)
Frequency not known4
Blood and lymphatic system disorders
Lymphadenopathy
Thrombocytopenia (some very rare cases were severe with platelet counts less than 5,000 per mm3)
Immune system disorders
Allergic reactions including anaphylactic shock (in rare cases), anaphylaxis
Metabolism and nutrition disorders
Loss of appetite
Nervous system disorders
Headache
Encephalomyelitis, Guillain-Barré syndrome, convulsions, neuritis, neuralgia, paraesthesia, syncope, presyncope
Vascular disorders
Vasculitis that may be associated with transient renal involvement
Gastrointestinal disorders
Nausea, Diarrhoea
Vomiting
Skin and subcutaneous tissue disorders
Generalised skin reactions including erythema multiforme, erythema, urticaria, pruritus or non-specific rash, angioedema
Musculoskeletal and connective tissue disorders
Myalgia1, Arthralgia1
Muscular weakness, pain in extremity
General disorders and administration site conditions
Injection site pain, Fatigue
Ecchymosis*, Erythema, Induration, Influenza-like illness2, Chills, Fever (≥38oC)3
Extensive swelling of injected limb lasting more than one week, injection-site cellulitis-like reaction, asthenia, malaise, pyrexia
*Injection site bruising
1 Reported as Common (≥1/100 to <1/10) in elderly subjects 65 years and older
2 Unsolicited adverse reaction reported in elderly subjects 65 years and older
3 Reported as Uncommon (≥1/1,000 to <1/100) in elderly subjects 65 years and older
4 Adverse reactions reported from post-marketing surveillance for Adjuvanted Trivalent or Quadrivalent Influenza Vaccine Seqirus formulations.
Paediatric population
There are limited data for Adjuvanted Trivalent Influenza Vaccine Seqirus in the paediatric population.
Reporting of suspected adverse reactions
Reporting suspected adverse reactions after authorization 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 website: www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store.
4.9. Overdose
Overdosage is unlikely to have any untoward effect.
💬 Ask about this leaflet
Ask anything about Adjuvanted Trivalent Influenza Vaccine (Surface Antigen, Inactivated) Seqirus suspension for injection in pre-filled syringe. The assistant answers only from this leaflet — if the leaflet does not cover it, it will say so. It does not give medical advice.
Answers come from the patient leaflet published on the electronic medicines compendium (emc). They are not medical advice. Ask a pharmacist or your GP if you are unsure. For urgent help call NHS 111, or 999 in an emergency.