Respiratory Syncytial Virus (RSV)

What Is Respiratory Syncytial Virus (RSV)?

Respiratory syncytial (sin-SISH-uhl) virus (RSV) is a common virus that infects the nose, throat, lungs, and breathing passages. It spreads through droplets from an infected person when they cough, sneeze, or kiss. You can also catch it by touching surfaces with the virus on them and then touching your eyes, nose, or mouth.

RSV can live for many hours on hard surfaces like tables and cribs, but it does not last as long on soft surfaces like tissues or hands. Children are often exposed to RSV outside the home at school or daycare and can bring it home to others. RSV is so common that almost all children will have had it by their 2nd birthday.

While RSV can be serious for very young children and older adults, it can affect people of any age. Roughly 80% of children younger than age 2 years who are hospitalized with RSV do not have risk factors.

Burden

Even though RSV often causes mild, cold-like symptoms, it can be serious for infants, toddlers, and older adults, and can lead to severe illness and hospitalization. In the US, RSV is the most common cause of hospitalization in children younger than 1 year old.

• Each year in the US, RSV leads to approximately 2.1 million outpatient visits and 58,000-80,000 hospital stays among children younger than 5 years

RSV is also becoming more recognized as a major cause of respiratory illness in adults.

• Each year in the US, RSV is estimated to cause 100,000-160,000 hospitalizations in adults age 60 years and older

The actual burden among all age groups is likely even higher due to underreporting of RSV infections.

Those at highest risk for severe disease from an RSV infection include:

• premature infants and infants age 6 months and younger
• adults with chronic heart or lung disease or certain other underlying medical conditions, including diabetes or obesity
• adults with weakened immune systems
• older adults, especially those who are frail or live in a nursing home

For additional information, read the NFID Call to Action: Reducing the Burden of RSV across the Lifespan (2022).

Symptoms

RSV symptoms are similar to those of other respiratory viruses, including influenza (flu) and COVID-19, and may include runny nose, coughing, sneezing, fever, loss of appetite, and wheezing.

In young infants, the only symptoms may be fussiness, less activity, and trouble breathing. People with RSV usually start showing symptoms 4-6 days after getting infected. Healthy adults may not have many symptoms but can still spread the virus to others.

Most people with RSV are contagious for 3-8 days and get better in 1-2 weeks. However, some infants and people with weakened immune systems can keep spreading the virus for up to 4 weeks, even after they feel better.

In the US, RSV typically spreads in fall and winter, like other seasonal viruses such as flu. Because RSV symptoms are similar to flu or COVID-19, it can be hard to know if someone has RSV without a confirmed lab test.

Prevention

The best ways to help prevent the spread of RSV include:

• Cover coughs and sneezes
• Wash hands often with soap and water for at least 20 seconds
• Avoid close contact with others who are sick
• Avoid touching your face, particularly eyes, nose, and mouth
• Clean frequently touched surfaces (such as doorknobs)
• Consult a healthcare professional if you have cold-like symptoms that linger or worsen
• Get immunized to protect against severe RSV as recommended

Vaccines and preventive monoclonal antibodies can help protect against RSV:

Adults: A single dose of RSV vaccine is recommended to protect all adults age 75 years and older and adults age 50-74 years who are at increased risk of severe RSV disease.

Infants: 2 RSV immunization options are available to protect infants from severe RSV—either a maternal RSV vaccine given to the pregnant mother or an RSV monoclonal antibody given to the infant.

The Centers for Disease Control and Prevention (CDC) has updated recommendations for RSV vaccines in adults. CDC recommends RSV vaccination for:

• All adults age 75 years and older
• Adults age 50–74 years who are at increased risk of severe RSV, including:
  • Those with certain chronic health conditions, such as lung disease, heart disease, or weakened immune systems
  • Those who live in nursing homes
• RSV vaccination is currently recommended as a single lifetime dose

CDC recommends protecting all infants against severe RSV either through a maternal RSV vaccine given to the pregnant mother or an RSV monoclonal antibody given to the infant.

• RSV vaccine for pregnant women: CDC recommends the maternal RSV vaccine (Abrysvo^®) for pregnant women to help protect infants against severe illness after birth. CDC recommends seasonal administration of 1 dose of the maternal RSV vaccine during weeks 32-36 of pregnancy during September-January.
• RSV preventive monoclonal antibody for infants: CDC recommends 1 dose of monoclonal antibody for all infants born to mothers who did not receive a maternal RSV vaccine during pregnancy. The dose should be given to infants shortly before the RSV season, or within 1 week after birth if born during October-March in most of the US.
  • Some children younger than age 19 months who are at increased risk for severe RSV may also need a dose shortly before their second RSV season.

Treatment

There are currently no specific antiviral medications or treatments for RSV disease. The primary treatment for RSV is supportive care and may include oxygen and respiratory care treatments.

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Updated July 2025

Sources: American Academy of Pediatrics and Centers for Disease Control and Prevention