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.
Beyfortus 100 mg solution 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 Nirsevimab 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
What Beyfortus is Beyfortus is a medicine given as an injection to protect babies and children less than 2 years of age against respiratory syncytial virus (RSV). RSV is a common respiratory virus that usually causes mild symptoms comparable to the common cold. However, especially in babies, vulnerable children and older adults, RSV can cause severe illness, including bronchiolitis (inflammation of the small airways in the lung) and pneumonia (infection of the lungs) that may lead to hospitalisation or even death. The virus is usually more common during the winter. Beyfortus contains the active ingredient nirsevimab which is an antibody (a protein designed to attach to a specific target) that attaches to a protein that RSV needs to infect the body. By attaching to this protein, Beyfortus blocks its action, thereby stopping the virus from entering and infecting human cells. What Beyfortus is used for Beyfortus is a medicine to protect your child from getting RSV disease.
2.
What you need to know before your child is given Beyfortus
Your child should not use Beyfortus if he or she is allergic to nirsevimab or any of the other ingredients of this medicine (listed in section 6). Inform your child's doctor, pharmacist or nurse if this applies to your child. If you are not sure, check with your child's doctor, pharmacist or nurse before the medicine is given. If your child shows signs of a severe allergic reaction contact the doctor immediately.
Warnings and precautions Tell your doctor or seek medical help immediately if you notice any signs of an allergic reaction, such as:
- difficulty breathing or swallowing
- swelling of the face, lips, tongue or throat
- severe itching of the skin, with a red rash or raised bumps Talk to your healthcare professional before your child is given Beyfortus if they have low numbers of blood platelets (which help blood clotting), a bleeding problem or bruise easily or if they are taking an anticoagulant (a medicine to prevent blood clots). In certain chronic health conditions, where too much protein is lost via the urine or the gut, for example nephrotic syndrome and chronic liver disease, the level of protection of Beyfortus may be reduced. Beyfortus contains 0.1 mg of polysorbate 80 in each 50 mg (0.5 mL) dose and 0.2 mg in each 100 mg (1 mL) dose. Polysorbates may cause allergic reactions. Tell your doctor if your child has any known allergies. Children and adolescents Do not give this medicine to children between the age of 2 and 18 years of age because it has not been studied in this group. Other medicines and Beyfortus Beyfortus is not known to interact with other medicines. However, tell your doctor, pharmacist or nurse if your child is taking, has recently taken or might take any other medicines. Beyfortus may be given at the same time as vaccines that are part of the national immunisation program.
3.
How to take it
Beyfortus is given by a healthcare professional as an injection in the muscle. It is usually given in the outer part of the thigh. The recommended dose is:
- 50 mg for children weighing less than 5 kg and 100 mg for children weighing 5 kg or more in their first RSV season.
- 200 mg for children who remain vulnerable to severe RSV disease in their second RSV season (given as 2 x 100 mg injections at separate sites). Beyfortus should be given before the RSV season. The virus is usually more common during the winter (known as the RSV season). If your child is born during the winter, Beyfortus should be given after birth. If your child is to have a heart operation (cardiac surgery), he or she may be given an extra dose of Beyfortus after the operation to ensure they have adequate protection over the remainder of the RSV season. If you have any further questions on the use of this medicine, ask your doctor, pharmacist or nurse.
4.
Possible side effects
Like all medicines, this medicine can cause side effects, although not everybody gets them.
Side effects can include: Uncommon (may affect up to 1 in 100 children)
- rash
- injection site reaction (i.e. redness, swelling, and pain where the injection is given)
- fever Not known (cannot be estimated from available data)
- allergic reactions Reporting of side effects If your child gets any side effects, talk to your doctor, pharmacist or nurse. This includes any possible
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
Beyfortus
Your doctor, pharmacist or nurse is responsible for storing this medicine and disposing of any unused product correctly. The following information is intended for healthcare professionals. Keep this medicine out of the sight and reach of children. Do not use this medicine after the expiry date which is stated on the carton after EXP. The expiry date refers to the last day of that month. Store in a refrigerator (2°C – 8°C). After removal from the refrigerator, Beyfortus must be kept at room temperature (20°C – 25°C), protected from light and used within 48 hours or discarded. Keep the pre-filled syringe in the outer carton in order to protect from light. Do not freeze, shake or expose to direct heat. Any unused medicine or waste material should be disposed of in accordance with local requirements.
6.
Contents of the pack and other information
What Beyfortus contains • The active substance is nirsevimab.
- One pre-filled syringe of 0.5 mL solution contains 50 mg nirsevimab.
- One pre-filled syringe of 1 mL solution contains 100 mg nirsevimab. •
The other ingredients are L-histidine, L-histidine hydrochloride, L-arginine hydrochloride, sucrose, polysorbate 80 (E433), and water for injections.
What Beyfortus looks like and contents of the pack Beyfortus is a colourless to yellow solution for injection. Beyfortus is available as:
- 1 or 5 pre-filled syringe(s) without needles.
- 1 pre-filled syringe packaged with two separate needles of different sizes.
Not all pack sizes may be marketed. Marketing Authorisation Holder Sanofi 410 Thames Valley Park Drive Reading Berkshire RG6 1PT United Kingdom Tel: 0800 035 2525 Manufacturer AstraZeneca AB Karlebyhusentren, Astraallen 152 57 Södertälje Sweden This leaflet was last revised in April 2026 © Sanofi 2022 BEYFORTUS is a trademark of the Sanofi group of companies. ————————————————————————————————————————–The following information is intended for healthcare professionals only: In order to improve the traceability of biological medicinal products, the name and the batch number of the administered product should be clearly recorded. Visually inspect Beyfortus for particulate matter and discolouration prior to administration. Beyfortus is a clear to opalescent, colourless to yellow solution. Do not inject Beyfortus if the liquid is cloudy, discoloured, or it contains large particles or foreign particulate matter. Do not use if the Beyfortus pre-filled syringe has been dropped or damaged or the security seal on the carton has been broken. Administer the entire contents of the pre-filled syringe as an intramuscular injection, preferably in the anterolateral aspect of the thigh. The gluteal muscle should not be used routinely as an injection site because of the risk of damage to the sciatic nerve.
Frequently asked questions about Beyfortus 100 mg solution for injection in pre filled syringe
How do I take Beyfortus 100 mg solution for injection in pre filled syringe?
Beyfortus 100 mg solution for injection in pre filled syringe comes as injection containing 100mg. 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 Beyfortus 100 mg solution for injection in pre filled syringe?
The active substance in Beyfortus 100 mg solution for injection in pre filled syringe is nirsevimab.
Where does this information come from?
This leaflet reproduces the patient information leaflet approved for Beyfortus 100 mg solution 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 Beyfortus 100 mg solution 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: nirsevimab
- 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
Beyfortus is indicated for the prevention of Respiratory Syncytial Virus (RSV) lower respiratory tract disease in:
i. Neonates and infants during their first RSV season
ii. Children up to 24 months of age who remain vulnerable to severe RSV disease through their second RSV season (see section 5.1).
Beyfortus should be used in accordance with official recommendations.
4.2. Posology and method of administration
Posology
Infants during their first RSV season
The recommended dose is a single dose of 50 mg administered intramuscularly for infants with body weight <5 kg and a single dose of 100 mg administered intramuscularly for infants with body weight ≥5 kg.
Beyfortus should be administered from birth for infants born during the RSV season. For others born outside the season Beyfortus should be administered ideally prior to the RSV season.
Dosing in infants with a body weight from 1.0 kg to <1.6 kg is based on extrapolation, no clinical data are available. Exposure in infants <1 kg is anticipated to yield higher exposures than in those weighing more. The benefits and risks of nirsevimab use in infants <1 kg should be carefully considered.
There are limited data available in extremely preterm infants (Gestational Age [GA] <29 weeks) less than 8 weeks of age. No clinical data available in infants with a postmenstrual age (gestational age at birth plus chronological age) of less than 32 weeks (see section 5.1).
Children who remain vulnerable to severe RSV disease through their second RSV season
The recommended dose is a single dose of 200 mg given as two intramuscular injections (2 x 100 mg). Beyfortus should be administered ideally prior to the start of the second RSV season.
For individuals undergoing cardiac surgery with cardiopulmonary bypass, an additional dose may be administered as soon as the individual is stable after surgery to ensure adequate nirsevimab serum levels. If within 90 days after receiving the first dose of Beyfortus, the additional dose during the first RSV season should be 50 mg or 100 mg according to body weight, or 200 mg during the second RSV season. If more than 90 days have elapsed since the first dose, the additional dose could be a single dose of 50 mg regardless of body weight during the first RSV season, or 100 mg during the second RSV season, to cover the remainder of the RSV season.
The safety and efficacy of nirsevimab in children aged 2 to 18 years have not been established. No data are available.
Method of administration
Beyfortus is for intramuscular injection only.
It is administered intramuscularly, preferably in the anterolateral aspect of the thigh. The gluteal muscle should not be used routinely as an injection site because of the risk of damage to the sciatic nerve. If two injections are required, different injection sites should be used.
For instructions on special handling requirements, see section 6.6.
4.3. Contraindications
Hypersensitivity to the active substance or to any of the excipients listed in section 6.1.
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.
Hypersensitivity including anaphylaxis
Serious hypersensitivity reactions have been reported following Beyfortus administration. Anaphylaxis has been observed with human immunoglobulin G1 (IgG1) monoclonal antibodies. If signs and symptoms of anaphylaxis or other clinically significant hypersensitivity reaction occur, immediately discontinue administration and initiate appropriate medicinal products and/or supportive therapy.
Clinically significant bleeding disorders
As with any other intramuscular injections, nirsevimab should be given with caution to individuals with thrombocytopenia or any coagulation disorder.
Immunocompromised children
In some immunocompromised children with protein-losing conditions, a high clearance of nirsevimab has been observed in clinical trials (see section 5.2), and nirsevimab may not provide the same level of protection in those individuals.
Polysorbate 80 (E433)
This medicine contains 0.1 mg of polysorbate 80 in each 50 mg (0.5 mL) dose and 0.2 mg in each 100 mg (1 mL) dose. Polysorbates may cause allergic reactions.
4.5. Interaction with other medicinal products and other forms of interaction
No interaction studies have been performed. Monoclonal antibodies do not typically have significant interaction potential, as they do not directly affect cytochrome P450 enzymes and are not substrates of hepatic or renal transporters. Indirect effects on cytochrome P450 enzymes are unlikely as the target of nirsevimab is an exogenous virus.
Nirsevimab does not interfere with reverse transcriptase polymerase chain reaction (RT-PCR) or rapid antigen detection RSV diagnostic assays that employ commercially available antibodies targeting antigenic site I, II, or IV on the RSV fusion (F) protein.
Concomitant administration with vaccines
Since nirsevimab is a monoclonal antibody, a passive immunisation specific for RSV, it is not expected to interfere with the active immune response to co‑administered vaccines.
There is limited experience of co‑administration with vaccines. In clinical trials, when nirsevimab was given with routine childhood vaccines, the safety and reactogenicity profile of the co‑administered regimen was similar to the childhood vaccines given alone. Nirsevimab can be given concomitantly with childhood vaccines.
Nirsevimab should not be mixed with any vaccine in the same syringe or vial (see section 6.2). When administered concomitantly with injectable vaccines, they should be given with separate syringes and at different injection sites.
4.6. Fertility, pregnancy and lactation
Not applicable.
4.7. Effects on ability to drive and use machines
Not applicable.
4.8. Undesirable effects
Summary of the safety profile
The most frequent adverse reaction was rash (0.7%) occurring within 14 days post dose. The majority of cases were mild to moderate in intensity. Additionally, pyrexia and injection site reactions were reported at a rate of 0.5% and 0.3% within 7 days post dose, respectively. Injection site reactions were non-serious.
Tabulated list of adverse reactions
Table 1 presents the adverse reactions reported in 2,966 term and preterm infants (GA ≥29 weeks) who received nirsevimab in clinical trials, and in post-marketing setting (see section 4.4).
Adverse reactions reported from controlled clinical trials are classified by MedDRA System Organ Class (SOC). Within each SOC, preferred terms are arranged by decreasing frequency and then by decreasing seriousness. Frequencies of occurrence of adverse reactions are defined 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) and not known (cannot be estimated from available data).
Table 1: Adverse reactions
MedDRA SOC
MedDRA Preferred Term
Frequency
Immune system disorders
Hypersensitivitya
Not known
Skin and subcutaneous tissue disorders
Rashb
Uncommon
General disorders and administration site conditions
Injection site reactionc
Uncommon
Pyrexia
Uncommon
a Adverse reaction from spontaneous reporting.
b Rash was defined by the following grouped preferred terms: rash, rash maculo-papular, rash macular.c Injection site reaction was defined by the following grouped preferred terms: injection site reaction, injection site pain, injection site induration, injection site oedema, injection site swelling.
Infants at higher risk for severe RSV disease in their first season
Safety was evaluated in MEDLEY in 918 infants at higher risk for severe RSV disease, including 196 extremely preterm infants (GA <29 weeks) and 306 infants with chronic lung disease of prematurity, or haemodynamically significant congenital heart disease entering their first RSV season, who received nirsevimab (n=614) or palivizumab (n=304). The safety profile of nirsevimab in infants who received nirsevimab in their first RSV season was comparable to the palivizumab comparator and consistent with the safety profile of nirsevimab in term and preterm infants GA ≥29 weeks (D5290C00003 and MELODY).
Children who remain vulnerable to severe RSV disease in their second season
Safety was evaluated in MEDLEY in 220 children with chronic lung disease of prematurity or haemodynamically significant congenital heart disease who received nirsevimab or palivizumab in their first RSV season and went on to receive nirsevimab entering their second RSV season (180 subjects received nirsevimab in both Season 1 and 2, 40 received palivizumab in Season 1 and nirsevimab in Season 2). The safety profile of nirsevimab in children who received nirsevimab in their second RSV season was consistent with the safety profile of nirsevimab in term and preterm infants GA ≥29 weeks (D5290C00003 and MELODY).
Safety was also evaluated in MUSIC, an open label, uncontrolled, single dose trial in 100 immunocompromised infants and children ≤24 months, who received nirsevimab in their first or second RSV season. This included subjects with at least one of the following conditions: immunodeficiency (combined, antibody, or other etiology) (n=33); systemic high-dose corticosteroid therapy (n=29); organ or bone marrow transplantation (n=16); receiving immunosuppressive chemotherapy (n=20); other immunosuppressive therapy (n=15), and HIV infection (n=8). The safety profile of nirsevimab was consistent with that expected for a population of immunocompromised children and with the safety profile of nirsevimab in term and preterm infants GA ≥29 weeks (D5290C00003 and MELODY).
The safety profile of nirsevimab in children during their second RSV season was consistent with the safety profile of nirsevimab observed during their first RSV season.
Term and Preterm Infants entering their first RSV season
Safety of nirsevimab was also evaluated in HARMONIE, a randomised open-label multicentre trial in 8 034 term and preterm infants (GA ≥29 weeks) entering their first RSV season (not eligible for palivizumab), who received nirsevimab (n=4 016) or no intervention (n=4 018) for the prevention of respiratory syncytial virus lower respiratory tract infection (RSV LRTI) hospitalisation. The safety profile of nirsevimab administered in the first RSV season was consistent with the safety profile of nirsevimab in the placebo-controlled trials (D5290C00003 and MELODY).
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 website: www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store.
4.9. Overdose
There is no specific treatment for an overdose with nirsevimab. In the event of an overdose, the individual should be monitored for the occurrence of adverse reactions and provided with symptomatic treatment as appropriate.
🇷🇴 Known in Romania as
Medicines sold in Romania with the same active substance: Cunoscut în România ca
- BEYFORTUS 100 mg prescriptionNIRSEVIMABUM · injection / infusion
- BEYFORTUS 50 mg prescriptionNIRSEVIMABUM · injection / infusion
Same active substance. The strength, the form and whether you need a prescription can differ. Always ask a pharmacist before you switch. Romanian medicines in the UK →
🇵🇱 Known in Poland as
Medicines sold in Poland with the same active substance: W Polsce znany jako
- BeyfortusNirsevimabum · injection / infusion
Same active substance. The strength, the form and whether you need a prescription can differ. Always ask a pharmacist before you switch. Polish medicines in the UK →
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Ask anything about Beyfortus 100 mg solution 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.