What Is RSV? Symptoms, Transmission, Treatment and Prevention

Created: 16.09.2024 · Last Updated: 12.08.2026 · Category: Paediatrics · Prepared by the Academic Hospital Web and Editorial Board.

Respiratory syncytial virus (RSV) is a very common respiratory virus that can infect the nose, throat and lungs. Most children encounter RSV during the first years of life.

Most RSV infections cause mild, cold-like illness. In young infants, however, RSV can cause serious lower respiratory tract infections including bronchiolitis and pneumonia.

Severe RSV does not occur only in premature babies or children with chronic disease. Very young, previously healthy infants can also develop severe illness, although prematurity and certain medical conditions further increase the risk.

What Is RSV?

RSV is an RNA virus belonging to the Pneumoviridae family. It infects cells throughout the human respiratory tract.

It can affect:

  • The nose and throat
  • The bronchi
  • The small airways called bronchioles
  • The lungs

RSV infection does not produce complete lifelong immunity. Reinfection can therefore occur throughout childhood and adulthood.

What Problems Can RSV Cause in Babies?

In babies and young children RSV can cause:

  • Upper respiratory tract infection
  • Bronchiolitis
  • Pneumonia
  • Middle-ear infection
  • Wheezing

Bronchiolitis is inflammation and narrowing of the small airways, usually caused by a viral infection in children under 2 years of age. RSV is one of its most important causes.

Mild cases may produce only a runny nose and cough, whereas severe disease can cause difficulty breathing, poor feeding and low blood oxygen levels.

Who Is at Higher Risk of Severe RSV?

Risk is higher particularly in:

  • Very young infants
  • Babies born prematurely
  • Children with chronic lung disease
  • Children with haemodynamically significant congenital heart disease
  • Children with weakened immune systems
  • Children with neuromuscular disorders or congenital abnormalities that interfere with clearing airway secretions
  • Some children with severe cystic fibrosis

Previously healthy young infants can nevertheless also require hospital treatment for RSV.

What Are the Symptoms of RSV?

Common symptoms include:

  • Runny nose
  • Nasal congestion
  • Cough
  • Sneezing
  • Fever
  • Reduced appetite or feeding
  • Wheezing
  • Rapid or difficult breathing

Very young infants may have less typical symptoms and can instead develop:

  • Irritability
  • Reduced activity
  • Feeding difficulty
  • Apnoea, or pauses in breathing

How Does RSV Spread?

RSV can spread through respiratory secretions released when an infected person coughs or sneezes.

Transmission can also occur through:

  • Close personal contact
  • Contaminated hands
  • Contaminated toys and frequently touched surfaces

followed by touching the eyes, nose or mouth.

Most people are contagious for several days. Some infants and immunocompromised individuals may continue shedding the virus for considerably longer.

How Is RSV Diagnosed?

Typical bronchiolitis can often be diagnosed from the history and physical examination without laboratory confirmation.

RSV testing is not required for every child.

When identifying the virus is clinically useful, respiratory samples can be tested using:

  • PCR or other nucleic-acid amplification tests
  • RSV antigen tests

PCR-based methods are highly sensitive for detecting RSV.

Testing is generally considered when the result can influence patient management, hospital infection control or other clinical decisions.

How Is RSV Treated?

Most RSV infections resolve without specific antiviral treatment. Management is mainly supportive.

For mild disease this may include:

  • Maintaining adequate fluids and feeding
  • Managing nasal obstruction appropriately
  • Monitoring breathing and general condition
  • Appropriate management of fever and discomfort when required

Children who require hospital treatment may need:

  • Supplemental oxygen
  • Fluid or feeding support
  • Advanced respiratory support in severe disease
Antibiotics do not treat RSV because RSV is a virus. Antibiotics should not be used routinely unless a bacterial infection is suspected. Bronchodilators such as salbutamol and systemic or inhaled corticosteroids are also not routinely recommended for uncomplicated bronchiolitis.

Which Symptoms Require Urgent Assessment?

Prompt medical assessment is required if a baby or child develops:

  • Significant difficulty breathing
  • Marked chest recession
  • Very rapid breathing
  • Blue or grey lips or skin
  • Pauses in breathing
  • Inability to feed or drink adequately
  • Marked drowsiness or difficulty waking
  • Signs of dehydration such as markedly reduced urine output

Breathing difficulty, poor feeding, cyanosis or pauses in breathing in a very young infant should be assessed without delay.

How Can RSV Be Prevented?

Measures that help reduce RSV transmission include:

  • Regular handwashing with soap and water
  • Covering coughs and sneezes
  • Avoiding touching the eyes, nose and mouth with unwashed hands
  • Cleaning frequently touched surfaces and toys
  • Reducing close contact between young babies and people with respiratory symptoms
  • Avoiding kissing babies while ill
  • Keeping babies and children away from tobacco smoke

During periods of high RSV circulation, reducing unnecessary exposure to crowded indoor environments may be reasonable for very young or high-risk infants.

What Are RSV Vaccines and Preventive Antibodies?

Options for protecting infants against severe RSV disease have changed substantially in recent years.

Two main preventive strategies are now used internationally:

Maternal RSV Vaccination

An RSV vaccine administered during pregnancy is intended to stimulate the mother's immune system to produce antibodies that cross the placenta and help protect the infant during the first months of life.

Monoclonal Antibodies for Infants

Long-acting antibodies such as nirsevimab and clesrovimab provide ready-made antibodies directly to the infant.

They are not vaccines. Rather than stimulating the infant's immune system to produce its own antibodies, they provide passive protection.

Palivizumab is an older RSV monoclonal antibody that can be administered in repeated doses to selected high-risk infants and young children.

Older information sometimes describes repeated RSV preventive injections as a “five-month vaccine course”. This is not technically correct. Vaccines and monoclonal antibodies are different interventions. The appropriate option depends on national recommendations, regulatory approval and availability, timing during pregnancy, the infant's age and individual risk factors.

The World Health Organization recommends that countries introduce appropriate infant protection strategies using maternal RSV vaccination or long-acting monoclonal antibodies.

Does RSV Cause Asthma Later in Life?

Children who have severe RSV lower respiratory tract disease in infancy have higher rates of recurrent wheezing and asthma later in childhood.

However, this association does not prove that RSV itself is the sole direct cause of asthma.

Genetic susceptibility, underlying airway characteristics, environmental exposures and immune responses may all contribute to the association.

Have Your Baby's Breathing Assessed

Cough, wheezing, rapid breathing, feeding difficulty or respiratory distress in a baby can be assessed by a paediatric healthcare professional.

Frequently Asked Questions

What is RSV?
RSV is a common respiratory virus that can infect the nose, throat and lungs. Most infections are mild, but RSV can cause serious lower respiratory tract disease such as bronchiolitis and pneumonia, particularly in young infants.
Can you get RSV more than once?
Yes. RSV infection does not produce complete lifelong immunity, so people can become infected more than once during their lives. Early infections, particularly in very young infants, may be more severe.
Does every child with suspected RSV need a test?
No. Typical bronchiolitis can often be diagnosed from the history and examination. Laboratory testing may be used when the result could affect treatment, hospital management or infection control. PCR-based tests are highly sensitive for detecting RSV.
Is RSV treated with antibiotics?
No. RSV is caused by a virus, so antibiotics do not treat the infection. Antibiotics are not routinely used unless a bacterial infection is also suspected. Treatment mainly consists of supportive care such as fluids, feeding support and oxygen when required.
Which RSV symptoms are dangerous?
Significant breathing difficulty, chest recession, blue or grey skin, pauses in breathing, inability to feed, marked drowsiness or signs of dehydration require prompt medical assessment. These signs are particularly important in very young infants.
Is nirsevimab an RSV vaccine?
No. Nirsevimab is a long-acting monoclonal antibody that provides passive immunity. Vaccines stimulate the immune system to produce its own protective response, while nirsevimab provides ready-made protective antibodies directly to the infant.
Can RSV vaccination during pregnancy protect the baby?
Maternal RSV vaccination aims to generate antibodies in the pregnant woman that cross the placenta and help protect the infant against severe RSV disease during the first months of life. Timing and eligibility should follow current recommendations from the relevant national health authorities.
Does RSV cause asthma later in life?
Children who have severe RSV lower respiratory tract disease in infancy have higher rates of recurrent wheezing and asthma later in childhood. However, this association does not prove that RSV alone directly causes asthma; genetic, environmental and immune factors may also contribute.
Academic Hospital note: Regulatory approval, availability and national recommendations for RSV vaccines and monoclonal antibodies can change over time. Current national guidance and individual risk factors should be considered when choosing an RSV prevention strategy during pregnancy or infancy. You can book an appointment.

References

  1. Academic Hospital. Respiratuvar Sinsityal Virüs Enfeksiyonları (RSV)
  2. World Health Organization. Respiratory Syncytial Virus (RSV)
  3. World Health Organization. WHO Position Paper on Immunization to Protect Infants Against RSV
  4. Centers for Disease Control and Prevention. Clinical Overview of RSV
  5. Centers for Disease Control and Prevention. Diagnostic Testing for RSV
  6. National Institute for Health and Care Excellence. Bronchiolitis in Children: Diagnosis and Management