RSV risk factors: who is at risk for severe RSV

What RSV is

Respiratory syncytial virus (RSV) is a common respiratory virus. It usually causes mild, cold-like symptoms, but it can cause serious lung infections, especially in infants, older adults and people with serious medical problems (MedlinePlus). In the US, RSV season is usually fall through spring (MedlinePlus).

RSV spreads through coughs and sneezes, direct contact such as kissing the face of a child who has RSV, and touching a surface with the virus on it and then your mouth, nose or eyes (MedlinePlus). CDC estimates that RSV was linked to 190,000 to 350,000 hospital stays and 10,000 to 23,000 deaths in the US from July 2024 to June 2025 (CDC 2026).

Who is at risk for severe RSV

RSV can affect people of all ages, and nearly all children have had it by age 2 (MedlinePlus). These groups are more likely to get very sick:

• Babies. RSV was the leading cause of hospital stays among US infants before infant protection was recommended for all babies. The hospital rate is highest in the first 6 months of life, and most babies hospitalized with RSV have no known risk factor, so all infants are at risk (ACIP 2025).
• Babies born early. Babies born at 30 weeks of pregnancy or earlier are hospitalized for RSV three times as often as babies born at term (ACIP 2023 (nirsevimab)).
• Some young children in their second RSV season, such as those with chronic lung disease from being born early, a severely weakened immune system or severe cystic fibrosis, and American Indian or Alaska Native children (ACIP 2023 (nirsevimab)).
• Older adults. MedlinePlus names older adults, especially those 65 and older (MedlinePlus). The hospital rate in adults rises with age and is highest at 75 and older (ACIP 2023).
• Long-term conditions. Adults with COPD, asthma, heart failure, coronary artery disease, stroke or other cerebrovascular disease, diabetes or chronic kidney disease are at higher risk of being hospitalized with RSV (ACIP 2023). ACIP also lists nerve and muscle conditions, liver disorders and blood disorders (ACIP 2023). See the COPD risk factors and heart failure risk factors guides.
• A weakened immune system, from a disease or from medicines or treatment that weaken it (MedlinePlus) (ACIP 2023).
• Living in a nursing home or other long-term care facility, and being frail (ACIP 2023).

Symptoms

Symptoms usually start about 4 to 6 days after infection and tend to come in stages rather than all at once (MedlinePlus):

• Runny nose, sneezing and less appetite (MedlinePlus)
• Cough, fever and wheezing (MedlinePlus)

In people at high risk, RSV can lead to bronchiolitis (swelling of the small airways in the lungs) or pneumonia (MedlinePlus). Most infections go away on their own in a week or two, and there is no specific treatment for RSV. Do not give aspirin to children, and do not give cough medicine to children under 4 (MedlinePlus).

Who CDC advises to get RSV protection

Adults. A single dose of RSV vaccine is recommended for all adults 75 and older, and for adults 50 to 74 who are at increased risk for severe RSV (CDC 2026). Adults who have already had an RSV vaccine should not get another dose (ACIP 2024).

Babies. CDC advises that all infants be protected against serious RSV lung infection with one of three product options (ACIP 2025):

• An RSV vaccine given during pregnancy at 32 to 36 weeks, during RSV season (September to January in most of the US) (ACIP 2023 (pregnancy)),
• Nirsevimab, a long-acting RSV antibody shot, or
• Clesrovimab, another long-acting RSV antibody shot (ACIP 2025).

The two antibody shots are for babies younger than 8 months who are born during or entering their first RSV season and who are not protected by the pregnancy vaccine (ACIP 2025).

No one product is preferred, and most babies do not need both the pregnancy vaccine and an antibody shot (ACIP 2025). Children 8 to 19 months old at increased risk can get nirsevimab before their second RSV season (ACIP 2023 (nirsevimab)).

Recommendations can change. Your doctor, pharmacist or your baby's doctor can tell you what fits you now.

Everyday steps that lower the risk of spread

• Wash your hands often with soap and water for at least 20 seconds, and avoid touching your face with unwashed hands (MedlinePlus).
• Avoid kissing, shaking hands and sharing cups or utensils when you or the other person is sick (MedlinePlus).
• Cover coughs and sneezes, clean surfaces you touch often, and stay home when sick (MedlinePlus).

Common questions

What are the RSV risk factors in adults?

Age 75 and older, and for adults 50 to 74, conditions that raise the risk of severe RSV (CDC 2026), such as COPD, asthma, heart failure, coronary artery disease, diabetes, chronic kidney disease, a weakened immune system, frailty or living in a nursing home (ACIP 2023).

How long is someone with RSV contagious?

Usually for 3 to 8 days. Infants and people with weakened immune systems can sometimes spread the virus for as long as 4 weeks (MedlinePlus).

My baby has no health problems. Are they still at risk?

Yes. Most babies hospitalized with RSV have no known risk factor, which is why CDC advises protection for all infants (ACIP 2025).

Related guide: measles risk factors, including whether a childhood MMR vaccine still protects you.

Related guide: who is at high risk for flu complications, with the warning signs that need care right away.

Related guide: pneumonia risk factors, including who is most at risk of serious pneumonia.