From September 2024, the HSE introduced the RSV Immunisation Pathfinder Programme, available for newborn infants born between September 2024 and February 2025. This pilot program administers a monoclonal antibody treatment, Nirsevimab under the trade name Beyfortus manufactured by Sanofi, which may offer protection against RSV for five months. The goal of the program is to reduce hospital admissions during peak season.
This article provides an overview of the potential risks associated with both the vaccine and the disease it targets, helping you make an informed decision.
Disease versus Vaccine Risk Summary
Risks from RSV
Risk of getting RSV
Every child will have got RSV at least once by their second birthday
Risk of hospitalisation from RSV
Approx 1 in 134 children (0.75%)
Risk of death from RSV
There is not enough data to calculate the exact risk
Risks from each dose of RSV Nirsevimab
1 dose for newborns between September and February (Side effects as per Nirsevimab patient information leaflet Sept 2024)
| Not known (cannot be estimated from available data) |
Allergic reactions |
| Up to 1 in 100 (1%) |
|
| Some other warnings and precautions | |
|---|---|
|
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What is Respiratory Syncytial Virus (RSV)?
Respiratory Syncytial Virus (RSV) is a common and highly contagious respiratory virus that produces cold symptoms such as coughing, sneezing, wheezing, decreased appetite, fever and malaise. By two years of age, most infants and children will have had RSV; Most children who develop an RSV infection will recover fully within one to two weeks without treatment and develop immunity.
The most severe and potentially life-threatening cases of RSV happen in the youngest infants, before the age of 6 months, as it can obstruct or prevent an infant from breathing through their nose as their lungs and chest are tiny. Studies show the majority of deaths in infants happen in areas facing socioeconomic challenges. Contributing factors include crowded living conditions, limited access to healthcare and exposure to indoor pollutants.
RSV season typically peaks from September to February, but since covid, its patterns have become more unpredictable. Covid policies such as masking, social distancing, and stay-at-home orders reduced exposure to RSV at the time which lowered community immunity. This may have damaged the transfer of passive immunity from mothers to infants, thereby causing an uptick in RSV in children.
What is the risk of getting RSV in Ireland?
Every child will have contracted RSV at least once by the time they are two years of age. The seasonal pattern of RSV is illustrated clearly in the chart below depicting hospitalisation, Intensive care unit admissions (ICU) and deaths. Admission to ICU for RSV is typically low.
According to the European Centre for Disease Control, In the EU, Norway and United Kingdom, RSV is responsible for the hospitalisation of around 213,000 children under five with some requiring intensive care, and roughly 158,000 adults each year. One in twenty elderly people in Europe contract RSV every year.
This translates to a hospitalisation risk of approximately 1 in every 134 children under 5 (0.75%) for a total population of under 5s of 28.5 million in areas with similar socio economic environment to Ireland.
What is the risk of death from RSV in Ireland?
Ireland does not publicly report RSV deaths among children under five in recent data so specific risk is hard to quantify. However, as can be seen from the line chart above which covers all ages, death from RSV is extremely rare (the line closest to the X axis). Total deaths for all ages in 2022 was approximately 37 and in 2023 was approximately 41.
Does Nirsevimab guarantee protection against RSV?
No your baby can still get RSV even after treatment with Nirsevimab.
Safety Data for Nirsevimab
Like all medicines, vaccines come with side effects, sometimes very serious. Parents need to research every vaccine and ensure benefits outweigh the risks.
- See Disease Vs Vaccine Risk Summary above for list of possible side effects from Nirsevimab.
- There is a warning on the patient information leaflet; your child should not use Beyfortus (Nirsevimab) if he or she is allergic to nirsevimab or any of the other ingredients of this medicine. However, since your baby is a newborn, you cannot know what they may be allergic to.
- Serious hypersensitivity reactions have been reported following Nirsevimab administration, including anaphylaxis.
- Nirsvimab contains Polysorbate 80 which may cause allergic reactions. Polysorbate 80 also known as Tween 80 facilitate drugs and compounds cross the blood-brain barrier (BBB) under specific conditions.
- Nirsevimab was approved for use in the EU and the UK in November 2022, following trials involving 3580 infants. A reduction in severe disease and hospitalisation was observed.
- A worrying observation in the FDA approval paperwork was an increase in all cause deaths in the nirsevimab arm of the various trials (12/3710 (0.32%) nirsevimab versus 4/1797 (0.22%) controls). There is no mention of this on the European Medicines Agency or MHRA websites, despite the same drug company results being submitted.
- In France, between September 11, 2023, and April 30, 2024, of 244,495 doses delivered, 198 adverse events were reported of which 153 were considered serious. There were also 3 reports of sudden infant death syndrome (SIDS), although researchers said at least one of them was likely not linked to the drug. The ANSM said each of the signals would be closely monitored in the future, but that a causal link between Beyfortus and those adverse events had not yet been established.
- Interaction with vitamin K (also given at birth) has not been tested.
What are the vaccine ingredients?
| Vaccine | Ingredients as listed on patient information leaflets |
|---|---|
| Nirsevimab (RSV) |
Active substances: nirsevimab monoclonal antibody
Other ingredients: L-histidine, L-histidine hydrochloride, L-arginine hydrochloride, [popup_anything id=”3109″], [popup_anything id=”2983″] |