Respiratory syncytial virus (RSV)

RSV virus

Respiratory syncytial virus (RSV) is a common respiratory virus that causes mild, cold-like symptoms. People who contract RSV usually recover in around a week without the need for medical treatment. However, in infants under six months of age, people over 65, and people with a compromised immune system, RSV can cause severe illness and death. 

Symptoms usually appear two to eight days after being infected.

RSV affects different age groups differently, but the most common symptoms of the condition include: 

  • Cough
  • Sneezing
  • Fever
  • Runny nose
  • Wheezing

Infants who contract RSV may develop different symptoms such as:

  • Irritability
  • Decrease in appetite
  • Changes in their breathing pattern
  • Apnoea (temporary cessation of breathing, especially during sleep)

In children under 5, RSV can also cause:

  • Rapid breathing
  • Trouble swallowing
  • Sepsis

Adults with RSV may also experience:

  • Sore throat
  • Headache
  • Congestion
  • Fatigue

Key facts

Risk for people

RSV can affect people at any age and almost all children will be infected with RSV by the time they are two years old. While most cases are mild, RSV can worsen existing medical conditions and cause serious complications that can be life-threatening. Complications of severe RSV infection include bronchiolitis, the inflammation of the small airways in the lung, and pneumonia, an infection of the lungs.

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. 

Those most at risk include premature infants and those under six months old, people over 65 and those with weakened immune systems or pre-existing conditions such as diabetes, heart disease, and lung disease. 

In infants and young children, the signs of severe RSV infection that require urgent medical attention are linked to difficulty breathing. Short shallow breaths, flaring of the nostrils when inhaling, noisy breathing, pauses in breathing, and caving of the chest signify the need for urgent medical care. In addition, parents should look for blue or grey colouring of the lips, mouth or fingernails as this is a sign of critically low blood-oxygen levels.  

Infants may also develop sepsis, an infection of the bloodstream that can cause a variety of symptoms including a drop in blood pressure, increase in heart rate and fever. 

How it spreads

RSV spreads from person to person via particles and droplets released into the air when an infected person breathes, speaks, coughs or sneezes.
Close contact such as kisses from parents to children can also spread the virus. 

RSV can also spread when respiratory droplets land on surfaces that other people touch. These people may then pick the virus up on their hands and become infected when they touch their nose, mouth or eyes. This is a common means of transmission for infants and young children who touch infected surfaces and toys or put them in their mouths. 

Vaccination and treatment

In 2023, the European Union approved the first RSV vaccine suitable for protecting infants up to six months of age as well as two vaccines for older adults. When given to a mother during pregnancy, the antibodies generated in response to the vaccine can cross the placenta to the foetus, protecting the child for up to six months following birth. 

Mild cases of RSV do not usually require any treatment as people recover on their own after a few days. Infants under six months may require a hospital stay to monitor their breathing and oxygen levels. In severe cases, hospital treatment can include supportive care, breathing support and anti-viral medication alongside specific treatments for complications that may arise.

In some cases, children under 2 may be given medication by their doctor to reduce their risk of severe disease should they become infected.

Protective measures

In addition to vaccination, general prevention measures are the same as for most other respiratory viruses. These include:

  • avoiding close contact with sick people
  • washing or cleaning hands frequently
  • avoiding touching your eyes, nose or mouth.
  • maintaining good respiratory hygiene and cough etiquette

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