Vaccinarsi in Sardegna

Respiratory Syncytial Virus (RSV) is the main agent of bronchiolitis and is the leading cause of hospitalisation in children under one year of age. The disease is so widespread and transmissible that more than 60% of children contract the infection within the first year of life, and practically all by the age of two years. Considering an entire birth cohort, about 20% of newborns develop a serious infection requiring medical attention, and almost 4% of the cohort in the first year of life require hospitalisation. Notably, 20% of those hospitalised end up in intensive care.

Worldwide, an estimated 33 million lower respiratory tract infections among children under five years of age are reported annually, of which 3.6 million lead to hospitalisation, collectively resulting in 100,000 deaths. This impact translates into an estimated cost of approximately EUR 4.82 billion. Additionally, about 70% of children who have had RSV bronchiolitis experience recurrent bronchospasm in subsequent years, and almost 50% develop bronchial asthma. The cohort of susceptible infants represents the largest reservoir for the circulation of the virus, constituting an important source of infection for the elderly and other at-risk individuals (particularly those with COPD, asthma, heart conditions, etc.). The grave impact of adult infection has only recently been widely recognised, both in terms directly related to the infection and indirectly, as an aggravation of underlying pathologies. Therefore, targeted vaccines have recently been developed for these categories of patients, but a combined strategy of prophylaxis for newborns and at-risk adults represents the most rapid and effective way to control all these diseases.

For newborns, it is necessary to induce the earliest possible protection, given that the disease is more severe the earlier it is contracted. In this sense, infant vaccination is not a viable strategy (vaccinations are administered from 60 days of age and require several doses and a physiological lapse of time to produce an effective active response). Thus, two other possible strategies remain:

1. Vaccinoprophylaxis of the pregnant woman: This approach aims to protect the mother, who will therefore not be able to transmit the infection to the newborn, as well as directly protecting the unborn child through the passage of maternal antibodies into the fetal circulation.
2. Passive immunoprophylaxis of the newborn with specific monoclonal antibodies: This strategy has already been successfully adopted in high-risk infants (premature and those with underlying pathologies, particularly pulmonary dysplasia) with the administration of the first monoclonal antibody specifically made for this purpose (Palivizumab). However, this first prophylaxis has the inherent limitation of short-lasting protection, requiring repeated administrations over the epidemic season (up to five doses). This results in a risk of adverse reactions proportional to the doses administered, relatively low compliance to prophylaxis by the infant's families, and a high cost.

The recent availability of a new monoclonal antibody (Nirsevimab) with a long half-life, which enables sustained protection throughout the epidemic season with a single dose, has profoundly changed the outlook for its use, in terms of reducing the risk of adverse reactions, acceptability to parents, practicality of supply and cost reduction. Therefore, this has prompted its being offered, no longer solely to high-risk infants but universally to all infants during their first epidemic season, see annex - Posizione del Board del Calendario Vaccinale per la Vita sugli anticorpi monoclonali RSV (Vaccine for Life Calendar Board position on RSV monoclonal antibodies).

Several countries (Spain and France) have already made use of this prevention strategy and, in Italy, the first region to do so is Valle d'Aosta, which led the way last season by implementing a universal prevention programme against RSV to protect all children in their first year of life with the monoclonal antibody Nirsevimab. Real-world data were presented at the ESPID Congress in May 2024 and in the journal Vaccines. In addition to the safety data on the use of the monoclonal antibody, the high efficacy data were confirmed: no cases of hospitalisation for bronchiolitis or lower respiratory tract diseases caused by RSV were recorded among infants who had received prophylaxis, compared to 9.7% among those who had not been prophylaxed.

For this reason, by Regional Law no. 14 of 2 October 2024, ‘Urgent provisions on passive immunisation against Respiratory Syncytial Virus (RSV) infection’, the Region of Sardinia also authorised the implementation of a passive immunisation campaign against RSV infection in infants before the age of one for the 2024-2025 season. Following the purchase of the necessary doses for the campaign, these were distributed to the regional birth centres with the following indications:

• newborns should be administered with the 50 mg dose of Nirsevimab while in the neonatal ward, starting on the second day of life. It is advisable to keep track of the administration and to communicate this on the discharge card to their community paediatricians of choice;
• in neonatal units, neonatal pathology units and neonatal intensive care units, the 50 mg dose of Nirsevimab will be administered: a) to babies admitted under 5 kg, even if they are over 28 days old; b) to babies who have not reached 5 kg and have not received 5 doses of Palivizumab, and who can finish prophylaxis with a single dose of Nirsevimab.

In accordance with the principles of universality, equity and solidarity that characterise our National Health Service, even babies born at term in Sardinia will now have the opportunity to be protected against this very serious infection. Passive immunoprophylaxis has thus begun in our Region, with the first newborn in Sassari receiving their dose last Tuesday, 24 December.

‘The dose was administered at the Neonatology of the AOU of Sassari,’ reports Dr. Maria Antonia Cossu, head of the SC of NICU and Neonatology, in accordance with the internal protocol (attached), in compliance with the recommendations of the Italian Society of Neonatology.

For its tolerability, ease of use, indication and efficacy this passive immunoprophylaxis is comparable to that of a vaccine. For this reason, the Board of Scientific Societies in charge of the prevention of infectious diseases indicate that in the future we will no longer use the term ‘Vaccination Schedule’ but rather generically ‘Immunoprophylaxis Schedule’, since alongside active immunoprophylaxis (Vaccination) passive immunoprophylaxis has also been rightly included, thanks to the new monoclonal antibodies with a long half-life.

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