RSV (Respiratory Syncytial Virus)

How RSV spreads

RSV spreads through droplets from coughs and sneezes, direct contact such as kissing, and touching contaminated surfaces then the face. It can survive on hard surfaces for hours. People are usually contagious for 3 to 8 days, but young infants and people with weak immune systems can spread it for up to 4 weeks. Symptoms start 4 to 6 days after exposure.

Symptoms

In babies and young children

• runny nose and decreased appetite first
• cough, sneezing and fever after 1 to 3 days
• wheezing
• fast or labored breathing
• in very young infants: irritability, poor feeding, lethargy and apnea (pauses in breathing), sometimes without fever

In older children and adults

Usually symptoms like a common cold: runny nose, sore throat, cough, headache and mild fever. In older adults and people with chronic conditions, RSV can cause pneumonia, worsen asthma, COPD and heart failure, and lead to hospitalization.

Bronchiolitis

RSV is the most common cause of bronchiolitis, inflammation of the smallest airways in the lungs in children under 2. Mucus and swelling narrow these tiny airways, causing wheezing, crackles and difficulty breathing. Symptoms usually peak on days 3 to 5. The cough can last 2 to 4 weeks.

Who is at high risk

• babies under 6 months, especially under 2 months
• premature babies
• children with congenital heart disease, chronic lung disease or weak immune systems
• children with neuromuscular disorders who have trouble clearing mucus
• adults over 60, especially over 75
• adults with chronic heart or lung disease, diabetes, kidney disease or weak immune systems
• residents of nursing homes

Diagnosis

RSV is usually diagnosed from symptoms during RSV season. Testing with a nasal swab (rapid antigen or PCR, often combined with flu and COVID-19 tests) is used for hospitalized patients and high-risk adults. Chest X-rays are not routinely needed in bronchiolitis, according to the American Academy of Pediatrics. Pulse oximetry checks oxygen levels.

Treatment

There is no routine antiviral treatment for RSV. Care focuses on supporting breathing and hydration.

At home

• suction the nose with saline drops and a bulb syringe before feeds and sleep
• offer small, frequent feeds or fluids
• treat fever with acetaminophen (paracetamol), or ibuprofen for babies over 6 months, following the label dose for weight. Never give aspirin to children or teenagers
• use a cool-mist humidifier
• keep the child upright for feeds
• avoid smoke exposure
• cough and cold medicines are not recommended for children under 6

In hospital

• oxygen if levels are low
• high-flow nasal oxygen or breathing support in severe cases
• fluids by IV or feeding tube if a baby cannot feed
• suctioning

Antibiotics, bronchodilators such as albuterol, and steroids are not recommended for typical bronchiolitis.

Prevention

Immunization (CDC recommendations)

• During pregnancy: an RSV vaccine at 32 to 36 weeks, given in season, passes protective antibodies to the baby.
• For infants: a single dose of a long-acting monoclonal antibody (nirsevimab or clesrovimab) for babies under 8 months entering their first RSV season if the mother was not vaccinated, and a second-season dose for some high-risk toddlers.
• For older adults: a single RSV vaccine dose for everyone 75 and older, and for adults 50 to 74 at increased risk, according to current CDC guidance.

Everyday measures

• wash hands often
• avoid close contact with sick people, especially around newborns
• clean frequently touched surfaces
• cover coughs and sneezes
• keep sick children home from childcare

Frequently asked questions

What are the symptoms of RSV?

RSV usually starts with a runny nose, sneezing and reduced appetite, followed by cough, fever and sometimes wheezing. Young babies may only be irritable, feed poorly or have pauses in breathing. Older adults can develop pneumonia or worsening of heart and lung conditions.

How long does RSV last?

Most RSV infections improve within 1 to 2 weeks. In babies with bronchiolitis, symptoms often peak around days 3 to 5, and the cough can last 2 to 4 weeks. People are usually contagious for 3 to 8 days.

When should I take my baby to the hospital for RSV?

Seek emergency care if your baby is struggling to breathe, has blue lips, pauses in breathing, is very sleepy or floppy, or has significantly fewer wet diapers. Babies under 3 months with fever need prompt medical assessment.

Is RSV dangerous for adults?

Most healthy adults have only cold symptoms. RSV can be serious for adults over 60 and those with heart disease, lung disease, diabetes or weak immune systems, causing pneumonia and hospitalization. RSV vaccines are recommended for many older adults.

Is there a vaccine for RSV?

Yes. An RSV vaccine is recommended during pregnancy to protect newborns, long-acting antibody shots protect infants in their first RSV season, and RSV vaccines are recommended for adults 75 and older and those 50 to 74 at higher risk.