Influvac S

Package leaflet: Information for the user

Influvac S, injectable suspension in pre-filled syringe

Influenza vaccine (surface antigen, inactivated)
Season 2025/2026
Please read this leaflet carefully before you or your child is vaccinated, as it contains
important information for you and your child.

• Keep this leaflet. You may need to read it again.
• If you have any questions, ask your doctor, pharmacist, or nurse.
• This vaccine has been prescribed for you or your child. Do not give it to other people.
• If you or your child experience any side effects, including those not listed in this leaflet, talk to your doctor, pharmacist, or nurse. See section 4.

Contents of this leaflet:
1 What Influvac S is and what it is used for
2 What you need to know before you or your child is given Influvac S
3 How to use Influvac S
4 Possible side effects
5 How to store Influvac S
6 Contents of the pack and other information

1. What Influvac S is and what it is used for

Influvac S is a vaccine indicated for adults and children from 6 months of age. This vaccine helps protect you or your child against influenza. The use of Influvac S should be based on official recommendations.
When a person is given the Influvac S vaccine, the immune system (the body's natural defence system) produces protection (antibodies) against the disease. None of the ingredients in the vaccine can cause influenza.
Influenza is an illness that can spread rapidly and is caused by various strains which may change each year. For this reason, you or your child may need to be vaccinated every year. The risk of catching influenza is higher during the colder months, from October to March. If you or your child has not been vaccinated in the autumn, vaccination can still take place until spring, as the risk of catching influenza persists until then. Your doctor can advise you on the best time to get vaccinated.
Influvac S will protect you or your child against the three viral strains contained in the vaccine starting from 2 or 3 weeks after injection.
The incubation period of influenza is a few days, so if you or your child has been exposed to influenza immediately before or after vaccination, you or your child may still develop the disease.
The vaccine will not protect you or your child against the common cold, even though some symptoms may be similar to those of influenza.
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2. What you need to know before you or your child use Influvac S

To ensure that Influvac S is suitable for you or your child, it is important that you inform the doctor,
pharmacist, or nurse if you or your child are in any of the following conditions. If anything is unclear,
ask your doctor, pharmacist, or nurse for clarification.
Do not use Influvac S

• If you or your child are allergic (hypersensitive) to:
  • the active substances, or
  • any of the other components of Influvac S (see section 6), or
  • any component that may be present in very small amounts such as eggs (ovalbumin or chicken proteins), formaldehyde, cetrimonium bromide, polysorbate 80, or gentamicin (an antibiotic used to treat bacterial infections)

Warnings and precautions
You must inform the doctor before vaccination if you or your child have:

• a weakened immune response (immunodeficiency or use of medicines affecting the immune system)
• a bleeding disorder or a tendency to bruise easily

The doctor will decide whether you or your child should receive the vaccine. If you or your child currently have an illness with high fever or an acute infection, vaccination should be postponed until recovery. Fainting, feeling faint, or other stress-related reactions may occur after or even before any injection with a needle. Therefore, inform the doctor or nurse if you have experienced such reactions following a previous injection. If, for any reason, you or your child need to undergo a blood test within a few days after influenza vaccination, inform the doctor. This is because false positive results have been observed in some patients recently vaccinated. As with all vaccines, Influvac S may not fully protect all vaccinated individuals. Other medicines and Influvac S

• Inform the doctor, pharmacist, or nurse if you or your child are taking, have recently taken, or might take any other vaccine or medicine, including medicines without a prescription.
• Influvac S can be administered simultaneously with other vaccines in separate limbs. It should be noted that adverse reactions may be stronger.
• The immune response may be reduced during immunosuppressive treatment, such as with corticosteroids, cytotoxic drugs, or radiotherapy. Pregnancy and breastfeeding If you are pregnant, suspect you may be pregnant, planning to become pregnant, or are breastfeeding, consult your doctor before taking this medicine. Influenza vaccines can be used at any stage of pregnancy. More safety data are available for the second and third trimesters than for the first trimester; however, data from worldwide use of influenza vaccines do not indicate that the vaccine may have harmful effects on pregnancy or the child. Influvac S can be used during breastfeeding.

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Your doctor, pharmacist, or nurse will be able to decide whether you should receive Influvac
S. Consult your doctor, pharmacist, or nurse before taking any
medicine.
Driving and using machines
Influvac S does not affect or has a negligible effect on the ability to drive vehicles and use machines.
Influvac S contains sodium and potassium
This medicine contains less than 1 mmol (23 mg) of sodium per dose, i.e. essentially ‘sodium-free’.
This medicine contains potassium, less than 1 mmol (39 mg) per dose, i.e. essentially ‘potassium-free’.

3. How to use Influvac S

Dosage
A dose of 0.5 mL should be administered to adults.
Use in children and adolescents
A dose of 0.5 mL should be administered to children from 6 months up to 17 years of age.
Children under 9 years of age who have not previously been vaccinated with a seasonal influenza vaccine should receive a second dose after an interval of at least 4 weeks.
The safety and efficacy of Influvac S in infants below 6 months of age have not been established.
Route(s) and/or method of administration
The doctor or nurse will administer the recommended dose of the vaccine by injection into the muscle or deeply under the skin.
If you have any doubts about the use of this product, consult your doctor or pharmacist.

4. Possible side effects

Like all medicines, Influvac S may cause side effects, although not everybody gets them.
Seek immediate medical advice if you or your child experience any of the following side effects:
you or your child may need urgent medical treatment.

Severe allergic reactions (frequency unknown, occurred occasionally during general use of Influvac S):

• which may lead to a medical emergency with failure of the circulatory system to maintain adequate blood flow to organs (shock) in rare cases,
• swelling, particularly in the head and neck, including face, lips, tongue, throat, or any other part of the body (angioedema) in very rare cases.

The following side effects have been observed during clinical studies with Influvac S and/or with the quadrivalent influenza vaccine Influvac S Tetra. Their frequencies have been estimated as follows:

• very common (may affect more than 1 in 10 people);
• common (may affect up to 1 in 10 people);

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• uncommon (may affect up to 1 in 100 people);
• not known (adverse reactions from post-marketing experience; frequency cannot be estimated from the available data).

For all age groups, most of the above-mentioned reactions usually occurred within the first 3 days after vaccination and resolved spontaneously within 1–3 days of onset. The intensity of these reactions was generally mild.
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Reporting of adverse reactions
If you or your child experience any adverse reaction, including those not listed in this leaflet, please contact your doctor, pharmacist, or nurse. You may also report adverse reactions directly via the website https://www.aifa.gov.it/content/segnalazioni-reazioni-avverse . By reporting adverse reactions, you can help provide more information on the safety of this medicine.

5. How to store Influvac S

Keep this medicine out of the sight and reach of children.
Do not use Influvac S after the expiry date which is stated on the carton after "Exp.". The expiry date refers to the last day of that month.
Store Influvac S in a refrigerator (2°C-8°C). Do not freeze.
Keep the product in the original packaging to protect it from light.
Do not dispose of any medicine via wastewater or household waste. Ask your pharmacist how to dispose of medicines you no longer use. This will help protect the environment.

6. Package contents and other information

What Influvac S contains
The active substances are:
Surface antigens (haemagglutinin and neuraminidase) of the influenza virus from the following strains*:

• 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** per 0.5 mL dose

* propagated in embryonated hens' eggs obtained from pathogen-free chicken flocks
** haemagglutinin
This vaccine complies with the recommendations of the World Health Organization (WHO)
(northern hemisphere) and the European Union for the 2025/2026 season.
The other components are: potassium chloride, potassium dihydrogen phosphate, disodium phosphate dihydrate,
sodium chloride, calcium chloride dihydrate, magnesium chloride hexahydrate and water for injections.
Description of the appearance of Influvac S and contents of the pack
Influvac S is an injectable suspension contained in a pre-filled glass syringe (with or without needle)
fitted with a plunger stopper (bromobutyl rubber) containing 0.5 mL of a clear, colourless injectable liquid. Each syringe is for single use only.
Available in packs of 1 or 10 units.
Not all pack sizes may be marketed.
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Marketing Authorisation Holder
Viatris Healthcare Limited
Damastown Industrial Park,
Mulhuddart,
Dublin 15,
DUBLIN,
Ireland
Manufacturer:
Abbott Biologicals B.V.
Veerweg 12
NL - 8121 AA Olst
The Netherlands
For all information regarding this medicinal product, please contact the local representative of the Marketing Authorisation Holder.
This medicinal product is authorised in the European Economic Area (EEA) Member States and in the United Kingdom (Northern Ireland) under the following names:

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The following information is intended for healthcare professionals only:

As with all injectable vaccines, appropriate medical treatment and adequate supervision must always be readily available in case of an anaphylactic reaction following administration of the vaccine.
Allow the vaccine to reach room temperature. Shake before use.
Inspect visually prior to administration.
Do not use the vaccine if the colour has changed or if particulate matter or foreign particles are present in the suspension.
Do not mix with other medicinal products in the same syringe.
The vaccine must not be injected directly into a blood vessel.
Preferred sites for intramuscular injection are the anterolateral thigh (or deltoid muscle if muscle mass is adequate) in children from 6 to 35 months of age, or the deltoid muscle in children from 36 months of age and in adults.
Traceability
In order to improve traceability of biological medicinal products, the name and batch number of the administered product should be clearly recorded.
See also section 3: How to use Influvac S.
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