Respiratory syncytial virus, or RSV, is a virus that infects the lungs and respiratory tract causing cold-like symptoms. It's so common that most children have been infected with it by the time they're 2 years old. The virus can also infect adults. Self-care measures are usually all that's needed to relieve discomfort. But RSV can cause severe infection in premature babies, infants, children and adults with heart and lung disease, older adults, and anyone with a weakened immune system. For severe infections, a hospital stay may be needed.

Respiratory syncytial virus (RSV) causes infections of the lungs and respiratory tract. It's so common that most children have been infected with the virus by age 2. Respiratory syncytial (sin-SISH-ul) virus can also infect adults.

In adults and older, healthy children, respiratory syncytial virus (RSV) symptoms are mild and typically mimic the common cold. Self-care measures are usually all that's needed to relieve any discomfort.

RSV can cause severe infection in some people, including babies 12 months and younger (infants), especially premature infants, older adults, people with heart and lung disease, or anyone with a weak immune system (immunocompromised).


Symptoms of respiratory syncytial virus, or RSV, in adults and older children often include a mild stuffy or runny nose and dry cough. They also include a low-grade fever, sore throat, and mild headache. Severe infections may cause symptoms like fever, severe cough, wheezing, rapid or difficult breathing, and a bluish skin color. In infants, the chest muscles and skin may pull inward with each breath as they struggle to breathe. They may also cough, take shallow and rapid breaths, and feed poorly. Unusual tiredness and irritability are other infant symptoms. Because RSV and coronavirus disease 2019 (COVID-19) are both types of respiratory viruses, some symptoms of RSV and COVID-19 can be similar.

Signs and symptoms of respiratory syncytial virus infection most commonly appear about four to six days after exposure to the virus. In adults and older children, RSV usually causes mild cold-like signs and symptoms. These may include:

  • Congested or runny nose
  • Dry cough
  • Low-grade fever
  • Sore throat
  • Sneezing
  • Headache

In severe cases

RSV infection can spread to the lower respiratory tract, causing pneumonia or bronchiolitis — inflammation of the small airway passages entering the lungs. Signs and symptoms may include:

  • Fever
  • Severe cough
  • Wheezing — a high-pitched noise that's usually heard on breathing out (exhaling)
  • Rapid breathing or difficulty breathing — the person may prefer to sit up rather than lie down
  • Bluish color of the skin due to lack of oxygen (cyanosis)

Infants are most severely affected by RSV. Signs and symptoms of severe RSV infection in infants include:

  • Short, shallow and rapid breathing
  • Struggling to breathe — chest muscles and skin pull inward with each breath
  • Cough
  • Poor feeding
  • Unusual tiredness (lethargy)
  • Irritability

Most children and adults recover in one to two weeks, although some might have repeated wheezing. Severe or life-threatening infection requiring a hospital stay may occur in premature infants or in anyone who has chronic heart or lung problems.

RSV and COVID-19

Because RSV and coronavirus disease 2019 (COVID-19) are both types of respiratory viruses, some symptoms of RSV and coronavirus disease 2019 (COVID-19) can be similar. In children, COVID-19 often results in mild symptoms such as fever, runny nose and cough. For adults with COVID-19, symptoms may be more severe and may include trouble breathing.

Having RSV may lower immunity and increase the risk of getting COVID-19 — for kids and adults. And these infections may occur together, which can worsen the severity of COVID-19 illness.

If you have symptoms of a respiratory illness, your doctor may recommend testing for COVID-19.

When to see a doctor

Seek immediate medical attention if your child — or anyone at risk of severe RSV infection — has difficulty breathing, a high fever, or a blue color to the skin, particularly on the lips and in the nail beds.


Respiratory syncytial virus, or RSV, infection is caused by the virus entering the body through your eyes, nose, or mouth. The virus spreads easily through air droplets when a person coughs or sneezes near you. The virus also passes through direct contact like shaking hands and can live for hours on hard objects like countertops and crib rails. If you touch your mouth, nose, or eyes after touching an infected object, you're likely to pick up the virus.

Respiratory syncytial virus enters the body through the eyes, nose or mouth. It spreads easily through the air on infected respiratory droplets. You or your child can become infected if someone with RSV coughs or sneezes near you. The virus also passes to others through direct contact, such as shaking hands.

The virus can live for hours on hard objects such as countertops, crib rails and toys. Touch your mouth, nose or eyes after touching a contaminated object and you're likely to pick up the virus.

An infected person is most contagious during the first week or so after infection. But in infants and those with weakened immunity, the virus may continue to spread even after symptoms go away, for up to four weeks.

Risk factors

The risk of infection with respiratory syncytial virus, or RSV, is higher for children who attend child care centers or who have siblings in school. Those at increased risk of severe or sometimes life-threatening RSV infections include premature infants, young children born with heart or lung disease, children with weakened immune systems, and infants in crowded child care settings. Older adults and adults with asthma or other lung disease, heart failure, HIV or AIDS, leukemia, and certain transplanted organs are also at higher risk of severe infection.

By age 2, most children will have been infected with respiratory syncytial virus, but they can get infected by RSV more than once. Children who attend child care centers or who have siblings who attend school are at a higher risk of exposure and reinfection. RSV season — when outbreaks tend to occur — is the fall to the end of spring.

People at increased risk of severe or sometimes life-threatening RSV infections include:

  • Infants, especially premature infants or babies who are 6 months or younger
  • Children who have heart disease that's present from birth (congenital heart disease) or chronic lung disease
  • Children or adults with weakened immune systems from diseases such as cancer or treatment such as chemotherapy
  • Children who have neuromuscular disorders, such as muscular dystrophy
  • Adults with heart disease or lung disease
  • Older adults, especially those age 65 and older


Complications of respiratory syncytial virus include:

  • Hospitalization. A severe RSV infection may require a hospital stay so that doctors can monitor and treat breathing problems and give intravenous (IV) fluids.
  • Pneumonia. RSV is the most common cause of inflammation of the lungs (pneumonia) or the lungs' airways (bronchiolitis) in infants. These complications can occur when the virus spreads to the lower respiratory tract. Lung inflammation can be quite serious in infants, young children, older adults, immunocompromised individuals, or people with chronic heart or lung disease.
  • Middle ear infection. If germs enter the space behind the eardrum, you can get a middle ear infection (otitis media). This happens most frequently in babies and young children.
  • Asthma. There may be a link between severe RSV in children and the chance of developing asthma later in life.
  • Repeated infections. Once you've had RSV, you could get infected again. It's even possible for it to happen during the same RSV season. However, symptoms usually aren't as severe — typically it's in the form of a common cold. But they can be serious in older adults or in people with chronic heart or lung disease.


Protective medication for babies and high-risk young children

The U.S. Centers for Disease Control and Prevention (CDC) recommends use of a medication called nirsevimab (Beyfortus) to help protect infants from RSV. The medication, given as a single-dose shot before or during RSV season, is a monoclonal antibody. It's for babies younger than 8 months born during or entering their first RSV season.

The CDC also recommends that nirsevimab be given to children between the ages of 8 and 19 months old who are at high risk of severe RSV disease through their second RSV season. The RSV season typically is fall through spring.

Monoclonal antibodies are proteins made in a laboratory. They help the body to fight off harmful viruses that can cause disease. The protection provided decreases over time.

The medication palivizumab (Synagis), is also a monoclonal antibody. Given as a shot, it can help protect certain infants and children 24 months old and younger who are at high risk of serious complications from RSV. High-risk children in this age group include those who were born prematurely or who have ongoing lung disease, certain heart defects or a weakened immune system.

The first shot of palivizumab is given at the start of the RSV season, with monthly shots given during the season. Palivizumab is not recommended for healthy children or for adults.

These medications only help prevent RSV infection. They don't help treat it. Talk with your child's doctor or health care team to find out more about medication to help protect your child from RSV.

Lifestyle habits

These lifestyle habits can help prevent the spread of this infection:

  • Wash your hands often. Teach your children the importance of hand-washing.
  • Avoid exposure. Cover your mouth and nose when you cough or sneeze. Limit your baby's contact with people who have fevers or colds.
  • Keep things clean. Make sure kitchen and bathroom countertops, doorknobs, and handles are clean. Put used tissues in the trash right away.
  • Don't share drinking glasses with others. Use your own glass or disposable cups when you or someone else is sick. Label each person's cup.
  • Don't smoke. Babies who are exposed to tobacco smoke have a higher risk of getting RSV and potentially more-severe symptoms. If you do smoke, never do so inside the house or car.
  • Wash toys regularly. Do this especially when your child or a playmate is sick.