For the first time, the seasonal programme will be universal for babies born between 1 April 2026 and 31 March 2027, rather than being limited to particular higher-risk groups.

The programme is free and voluntary and will run until 31 March 2027.

RSV is extremely common, but it can be much more serious in babies, particularly during the first months of life. It is a major cause of respiratory infections including bronchiolitis and pneumonia in young children.

Under the new rules from Portugal’s Directorate-General of Health (DGS), babies born from 16 September until the end of March will normally receive the protection before leaving the maternity unit, preferably within the first 24 to 48 hours after birth.

Babies born earlier in the year won’t miss out.

Children born between 1 April and 15 September will be included in a catch-up programme running from 16 September until 30 October, with immunisation carried out through primary healthcare services.

Which children are covered?

There are three main groups included in the 2026-27 programme.

The first covers all babies born between 1 April 2026 and 31 March 2027.

Premature babies born between 1 January and 31 March 2026 are also eligible if they were born at no more than 33 weeks and six days of gestation and have not already been immunised.

A third group covers some children entering their second RSV season who are considered at greater risk of becoming seriously ill and who have not reached the age of two by 30 September.

This includes children with certain heart and lung conditions, pulmonary hypertension, respiratory complications associated with neuromuscular disease, some immune deficiencies, blood cancers and cystic fibrosis, among other conditions set out by the DGS.

Depending on the child and their circumstances, the protection will be given at a maternity unit, primary healthcare centre or hospital.

It’s not a traditional vaccine

Despite often being referred to as RSV vaccination, the protection being given to children is nirsevimab, a long-acting monoclonal antibody.

There is an important difference. A vaccine prompts the body to produce its own antibodies. Nirsevimab provides the antibodies directly, giving babies passive protection during the months when they are most vulnerable.

According to the DGS, that protection lasts for at least five to six months, covering much of the period when RSV is circulating.

Having already had RSV doesn’t necessarily mean a child should miss the programme either. The DGS says eligible children who have previously been infected can still receive nirsevimab because an earlier infection does not provide complete, lasting protection against catching the virus again.

The change means many parents won’t need to work out whether an otherwise healthy baby falls into a particular risk category this winter. If the child was born from 1 April onwards and will be going through their first RSV season, they are included.