Nirsevimab (Beyfortus) for babies: private RSV protection in London

No. It is a monoclonal antibody: a ready-made antibody given by injection. A vaccine teaches the body to make its own antibodies over several weeks; nirsevimab supplies the antibody directly, so a baby's immature immune system does not have to do the work. There is no RSV vaccine licensed for babies, so they are protected either through the mother's vaccine in pregnancy or by giving the baby the antibody itself.

Only if your baby was born before 32 weeks or has a high-risk condition listed in the Green Book: moderate or severe chronic lung disease of prematurity, a lung condition needing oxygen or long-term ventilation at the start of the season, haemodynamically significant congenital heart disease, or severe combined immunodeficiency. Those babies get it free through their neonatal or specialist team, so ask that team rather than booking with us. All other babies, including healthy full-term babies and those born at 32 to 36 weeks, are outside the NHS antibody programme; the NHS protects them through the mother's RSV vaccine in pregnancy only.

The maternal vaccine (Abrysvo) works well, especially when given at least two weeks before birth: UKHSA found an 81% reduction in RSV hospital admissions for newborns whose mothers were vaccinated 14 or more days before delivery, around 50% when it was given 10 to 13 days before, and 69% for premature babies. Nirsevimab can still be given to a baby whose mother was vaccinated; the NHS does this for its high-risk cohorts regardless. Whether it adds enough for your baby depends on when the vaccine was given, when your baby was born and any risk factors, which we discuss at the appointment.

Ideally September or early October, before RSV starts to circulate; the UK season runs October to February, peaking in late November and December. Babies born during the season should have it soon after birth, once home from hospital. A later dose still protects for the rest of the season, and we offer it until the end of February. RSV activity is low from March to August, so a baby born then is best immunised the following September.

There is no wait for the immune system to respond: levels of nirsevimab in the blood peak within about six days of the injection (range one to 28 days). Protection lasts at least five to six months from a single dose, a full RSV season. It is given once per season; the only extra dose the licence allows is after heart surgery with cardiopulmonary bypass.

In the MELODY trial of 3,012 term and late-preterm babies, one dose reduced medically attended RSV lower respiratory tract infection by 76.4% (95% CI 62.3 to 85.2) and RSV hospital admission by 76.8% (95% CI 49.4 to 89.4) over five months, compared with placebo. In HARMONIE, 8,058 babies in real-world conditions, RSV hospital admissions fell by 83.2% (95% CI 67.8 to 92.0) through the season. Early surveillance after routine use found 90% effectiveness against RSV admission in the USA and 82% in Galicia, Spain. All of these are relative reductions: nirsevimab does not prevent every RSV infection or hospital admission. Sources: SmPC section 5.1; Green Book RSV chapter, June 2026.

The evidence does not suggest so. Nirsevimab protects against disease more than against infection, so immunised babies still meet the virus and start building their own immunity. In MELODY, RSV illness in the second season was the same in the nirsevimab and placebo groups (1.0% each), so the study did not show illness being pushed into the following year.

Yes, at the same time as the routine childhood vaccines or around the same time, in a separate site (usually the other thigh). It does not interfere with the response to those vaccines, and in trials the side-effect profile when given together matched the vaccines given alone.

Uncommon in the trials (up to 1 in 100 babies) and mild: a rash within 14 days (0.7%), a fever (0.5%), or redness, swelling or pain at the injection site (0.3%) within 7 days. Allergic reactions, including serious ones, have been reported since the medicine came into use; how often is not known. Seek medical help straight away for difficulty breathing or swallowing, swelling of the face, lips, tongue or throat, or severe itching with a red rash or raised bumps. Full details are in the Patient Information Leaflet.

Not after a serious allergic reaction to nirsevimab, another monoclonal antibody or any of its ingredients (including polysorbate 80), and not for children aged 2 and over, who have not been studied. Tell us beforehand about low platelets, a bleeding disorder, easy bruising or a medicine to prevent clotting: the injection can often still be given, with a fine needle and firm pressure, though we may need advice from your baby's own team first. Protein-losing conditions such as nephrotic syndrome or chronic liver disease may reduce protection. A cold without a fever is no reason to delay; a fever or acute illness means we postpone until your baby has recovered.

By weight on the day: 50 mg under 5 kg, 100 mg from 5 kg, one injection either way and the same price. The questionnaire asks for your baby's latest weight so the right syringe is ready, and we weigh your baby in clinic to confirm. Second-season doses for children who remain vulnerable are 200 mg as two 100 mg injections at separate sites.

Yes. Nirsevimab is the medicine; Beyfortus is Sanofi's brand name for it, UK-licensed since November 2022 (PLGB 04425/0905) and used in the NHS programme. Our stock is the EU pack of Sanofi's Beyfortus: the same product, in the same 50 mg or 100 mg pre-filled syringe, from the same manufacturer as the UK pack, bought within the EU and imported by an MHRA-licensed wholesaler and importer before Sanofi began supplying private clinics in the UK in late September 2026. Because it is not the UK pack it counts in UK law as an unlicensed import, although the medicine itself is UK-licensed. When this limited stock has been used we will supply the UK pack, at a higher price. Our pharmacist will tell you which pack your baby is receiving and show you the carton, batch number and country of origin if you wish.

£780 for the first RSV season, whichever dose your baby needs, including the assessment, the injection, the Red Book entry and written record, and a GP letter if you want one. No separate consultation fee. The £25 deposit comes off the £780 at your visit; the only extra is a home visit, from £100, quoted in writing first.

This price reflects a limited quantity of the EU pack of Sanofi's Beyfortus (nirsevimab), the same product as the UK pack, bought before Sanofi began supplying private clinics in the UK in late September 2026. When that stock has been used we will supply the UK pack, which costs considerably more, and the price on this page will rise. The price you book at is the price you pay.

No. Nirsevimab is prescription-only, but our Superintendent Pharmacist is an independent prescriber, so assessment, prescription and injection happen in one appointment. You do not need to see your GP first.

We record the product name and batch number in your baby's Red Book, as required for all biological medicines, and give you a written record. With your consent we also write to your GP so it is added to your baby's NHS record.

Yes. Home visits across London cost from £100 call-out plus the price of the immunisation, which many parents prefer for a newborn in winter. Email info@hhpharmacy.co.uk with your postcode for a written quote.

A mild cold without a fever does not usually prevent it, though we assess your baby on the day. If your baby has a fever or is acutely unwell, call us on 020 7435 7075 before the appointment and we will move it; the injection waits until your baby has recovered, so that a symptom of the illness is not mistaken for a side effect.

Only children up to 24 months who remain vulnerable to severe RSV disease, for example with chronic lung disease of prematurity or significant congenital heart disease, are licensed for a second-season dose, and they are normally covered by the NHS through their specialist team. If you have been told your child is not covered, we can assess them: 200 mg as two injections, £1,560. A healthy child who has been through one RSV season is outside the licence, and we would not normally immunise them.