The National Immunisation Advisory Committee (NIAC) issued a recommendation in October for passive immunisation and vaccination against respiratory syncytial virus (RSV) in infants, children and adults aged ≥ 65 years.

In infants and children, NIAC recommends the passive immunisation of all infants against RSV during their first RSV season. Two forms of passive immunisation for infants against RSV have recently been authorised in the European Union: 

• A long-acting monoclonal antibody (nirsevimab) which can be administered to the infant directly
• A maternal vaccine RSVpreF (Abrysvo) which can provide infant protection through transplacental antibody transfer. 

Both products have acceptable safety and efficacy profiles. Further analysis of cost effectiveness and programmatic considerations is required to determine the most appropriate RSV passive immunisation strategy for Irish infants. NIAC stated that once available, nirsevimab should replace palivizumab for those high-risk infants and children who are currently eligible to receive palivizumab.

For adults ≥ 65 years, NIAC recommends RSV vaccination with either:

• RSVPreF3 (Arexvy) 
• RSVpreF (Abrysvo).

NIAC states the above two vaccines have similar safety and efficacy profiles and further analysis of cost and product availability is needed to determine which product is more suitable for use in Ireland. 

NIAC recommends that vaccine administration should aim to take place prior to the anticipated start of the RSV season where possible. In the event of limited supply of vaccines, priority should be given to those of more advanced age, those with significant comorbidities and those living in long-term care facilities for older adults as they are at the highest risk of severe RSV disease. 

RSV is a common contagious virus affecting the lungs and breathing passages. It is a disease of all ages that can exacerbate conditions such as chronic obstructive pulmonary disease (COPD), asthma and chronic heart failure (CHF), and can lead to severe outcomes, such as pneumonia, hospitalisation and death. 

RSV is the most common cause of hospital admissions due to acute respiratory illness in young children, as well as being the most common cause of bronchiolitis in infants. Approximately 90% of children are infected with RSV by two years of age, with RSV being the leading cause of LRTIs in babies. Cigarette smoke, overcrowding and lack of breastfeeding have been suggested to increase the frequency and severity of RSV infections.

RSV is also highly prevalent in older people and is associated with a substantial use of primary and secondary healthcare resources. Adults with underlying conditions are more likely to have higher hospitalisation rates for RSV than adults without these conditions. 

RSV has been a notifiable disease in Ireland since 2012, with activity monitored by the Health Protection Surveillance Centre (HPSC). There were 7,559 cases reported here during the 2022-2023 season, 231 of which were in adults over 60 years. Of these 2,231 cases, 636 cases presented to emergency departments. 

RSV is under-diagnosed and under-reported, due to low disease awareness, clinical similarity to seasonal influenza and lack of a specific treatment.  

A recent survey among 520 parents in Ireland, commissioned by Sanofi, found that almost four out of five (79%) Irish parents had heard of RSV but surprisingly their overall understanding of the resulting disease was low. When asked how their knowledge of the disease compared with other common childhood illnesses only one in five (22%) of parents surveyed had a good level of knowledge of RSV in comparison to infections such as the common cold (74%), influenza (52%) and pneumonia (38%).

Commenting that in children most cases of RSV are mild and clear up on their own, Prof Roy Philip, consultant neonatologist and paediatrician, UL Hospitals Limerick, said: “What’s concerning is that in a proportion of infants, RSV encounter could lead to lower respiratory tract problems such as bronchiolitis or pneumonia. In instances of obvious breathing difficulties significant pauses in breathing or unexplained lethargy/sleepiness, it’s imperative to seek urgent medical attention from emergency services. Very premature infants and those with certain underlying medical conditions are more vulnerable to severe RSV infections, at times warranting critical care.”

The HPSC has launched a new Respiratory Virus Notification Data Hub to provide the latest data for Covid-19, influenza and RSV cases in Ireland. As well as weekly epidemiological summaries, the hub includes data on hospitalised cases, ICU cases, deaths and outbreaks, allowing it to tell the story of the winter virus season as it happens in Ireland.
See: respiratoryvirus.hpsc.ie