For decades, respiratory syncytial virus (RSV) has traditionally been associated with childhood, particularly as a leading cause of bronchiolitis in infants and as a common cause of paediatric hospital admissions. However, in recent years, a significant impact of RSV on adults has been recognised, which can lead to serious complications, especially in older adults and people with chronic health conditions.
RSV circulates mainly during the colder months and can cause respiratory infections of varying severity. In vulnerable populations, it represents an important cause of hospitalisation and respiratory complications.
What is RSV and how does it affect adults?
Respiratory syncytial virus is a common respiratory virus that circulates mainly in autumn and winter. In young, healthy people, it usually causes mild, cold-like symptoms such as a blocked nose, cough, a low-grade fever and general malaise.
However, in people aged over 60, it can progress to more serious conditions, particularly in those with underlying heart or lung diseases (such as COPD or asthma), immunocompromised patients, or frail individuals. Complications associated with RSV include:
- Pneumonia
- Respiratory failure
- Worsening of chronic conditions
- Prolonged hospital stays
Increased life expectancy has led to a growing number of older people living with multiple chronic conditions and greater vulnerability to respiratory infections. Factors such as the progressive decline in immune response associated with ageing contribute to a higher risk of complications from the disease.
Why hasn’t there been a vaccine for adults until now?
For years, developing a vaccine against RSV proved to be a scientific challenge. Recent advances in understanding of the viral structure, particularly regarding the proteins that enable the virus to be recognised by the immune system, have made it possible to design vaccines that have shown promising results in clinical trials.
Currently, there are vaccines approved in Europe that have shown to reduce the risk of severe illness and hospitalisation associated with RSV in adults, especially among those in high-risk groups.
Who should be vaccinated against RSV?
Recommendations regarding the RSV vaccine for adults are evolving as more evidence becomes available. For this reason, current guidance focuses on specific groups. This does not mean that other groups cannot benefit, but that, at present, vaccination strategies prioritise the higher-risk groups and those for whom there is strongest evidence.
At present, the Spanish Ministry of Health recommends vaccination primarily for:
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People with significantly compromised immune systems (for example, following a transplant, undergoing active cancer treatment, on dialysis, or living with advanced HIV infection).
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People aged 60 or older residing in care homes or other social and healthcare institutions.
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In other cases, such as for older people or those with chronic conditions, vaccination can be assessed on an individual basis in consultation with the healthcare team.
The final decision should be made together with a healthcare professional, taking into account age, pre-existing conditions and clinical situation.
How is it different from the flu vaccine?
Although both illnesses affect the respiratory system and are prevalent in winter, influenza and RSV are caused by different viruses. As a result:
- The influenza vaccine does not protect against RSV.
- The RSV vaccine does not replace the influenza vaccine.
In many cases, both vaccines can be administered during the same seasonal vaccination program, where medically indicated.
Is the RSV vaccine safe?
Clinical studies have shown a favourable safety profile. The most common side effects are mild and similar to those of other vaccines:
- Pain at the injection site
- Fatigue
- Muscle pain
- Low-grade fever
As with any medical intervention, the decision to vaccinate should be made on an individual basis.
Can RSV be mistaken for flu or COVID-19?
The initial symptoms of RSV can be similar to those of other viral respiratory infections, such as flu or COVID-19, including a cough, fever and general malaise.
Older people or those with risk factors should seek medical assessment if respiratory symptoms worsen, persist or are accompanied by breathing difficulties.
Frequently asked questions about the RSV vaccine
Do I need an annual dose?
Recommendations may vary depending on the latest scientific evidence.
Can it be administered alongside other vaccines?
In many cases, yes, although this should always be confirmed with a healthcare professional.
If I have already had RSV, do I still need to be vaccinated?
Natural immunity is not always long-lasting, so vaccination may be worth considering.
A new landscape in respiratory disease prevention
The availability of RSV vaccines expands the range of preventive tools against respiratory diseases in adults, particularly those at higher risk, complementing influenza and COVID-19 vaccination. However, it is important to contextualise the current situation: according to the recommendations of the Spanish Ministry of Health, the roll-out of RSV vaccination in the adult population is expected to take place gradually between the 2026–2027 and 2028–2029 seasons.
At present, RSV vaccination is not included in the official routine immunisation schedule for adults in Catalonia. The only strategies currently in place relate to immunisation in infants.
In addition, the RSV vaccine for older adults is currently not funded by the public healthcare system in Catalonia, meaning that administration may involve a financial cost for the patient.
In this context, it is particularly important to assess each case individually, considering both the clinical indication and the actual options for vaccine access. If you have any doubts, it is recommended to consult your healthcare team to assess your individual risk and the available preventive options.
INFORMATION DOCUMENTED BY:
Dr Juan Manuel Pérez-Castejón, Geriatrics Department, Hospital Clínic Barcelona.
Montse Roldán, Care coordinator, Hospital Clínic Barcelona.
Dr Marta Aldea Novo, Department of Preventive Medicine and Epidemiology, Hospital Clínic Barcelona.
