Clesrovimab at a glance
Medicine class
Antiviral neutralising monoclonal antibody providing passive immunisation.
Licensed role
Prevention of RSV lower respiratory tract disease in neonates and infants during their first RSV season.
Administration
Intramuscular injection into the outer thigh, given by a healthcare professional.
Vaccines
Routine childhood vaccines may be given at the same visit using separate syringes and injection sites.
What is Clesrovimab used for?
Clesrovimab is used for prevention rather than treatment.
It is licensed to prevent RSV lower respiratory tract disease in neonates and infants during their first RSV season. NHS use follows current official eligibility recommendations.
How does Clesrovimab work?
Clesrovimab binds a conserved site on the RSV fusion protein and blocks the virus from entering cells. It supplies ready-made passive immunity rather than stimulating the infant to make antibodies as a vaccine does.
Clesrovimab preparations and strengths
Injection
Route: Parenteral
Strengths: 105 mg
How to take Clesrovimab
A healthcare professional injects clesrovimab into the anterolateral thigh muscle. It should not be injected into the buttock, mixed with other medicines, or use the same syringe or injection site as a vaccine.
Tell the healthcare professional about allergies, bleeding problems, easy bruising and treatments that reduce blood clotting.
The product must be visually checked and not shaken.
Clesrovimab side effects
Common or expected effects
- Pain, redness or swelling at the injection site
- Rash
Get urgent medical advice
- Severe allergic reaction, including facial or tongue swelling, difficulty breathing or swallowing, unresponsiveness, blue or grey colouring, or severe hives
Clesrovimab in pregnancy
Clesrovimab is licensed for administration to infants, not as maternal immunisation, so pregnancy is described as not relevant in its product information. The UK maternal RSV vaccination programme is separate.
Clesrovimab while breastfeeding
Lactation is described as not relevant because clesrovimab is administered directly to the infant. Breastfeeding is not listed as a contraindication to infant administration.
Clesrovimab interactions
Formal interaction studies have not been performed, but clinically important metabolic interactions are considered unlikely.
Routine childhood vaccines
May be given at the same visit using a separate syringe and injection site. They must not be mixed with clesrovimab.
Anticoagulants or other treatments affecting clotting
Intramuscular injection may increase bruising or bleeding, so the administering team should assess the infant’s bleeding risk.
Palivizumab
There are no data to guide substitution with clesrovimab after palivizumab prophylaxis has begun.
Common questions about Clesrovimab
Answers are fully visible for fast scanning and source review.
Is clesrovimab a vaccine?
No. It supplies passive RSV immunity directly rather than prompting the infant’s immune system to make antibodies.
Does it treat an existing RSV infection?
No. Its licensed role is prevention, not treatment of established RSV illness.
Can a baby still catch RSV?
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.