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Updated on December 9, 2025
Respiratory syncytial virus (RSV) is one of the most common causes of respiratory infections in the United States. The majority of RSV infections cause mild illness similar to a common cold. However, RSV can lead to severe illness and complications. These include lower respiratory infections like pneumonia, which make it difficult for a person to breathe. Each year, RSV results in tens of thousands of hospitalizations and thousands of deaths.
Certain factors put a person at greater risk for severe illness from an RSV infection. Age is one risk factor. Very young children (under the age of 2 years) and older adults are both considered high-risk groups. Risk increases significantly for any child born pre-term. It’s also higher for older adults living in care homes, environments where infections spread easily.
People with certain existing health conditions are at an increased risk for RSV, as well.
What conditions are associated with RSV?
The following health conditions can put a person at higher risk for severe RSV illness. This includes conditions that affect the heart, the lungs, and the immune system.
Congenital heart defects (CHD)
Congenital heart defects refer to structural abnormalities in the heart that are present at birth and can affect the heart’s normal function. Having CHD puts a person at greater risk for severe RSV illness and complications during childhood and throughout their life.
Chronic lung disease
A chronic condition is a health issue that lasts for a long time and requires ongoing treatment. In many cases, it’s lifelong. Chronic lung conditions include asthma, chronic obstructive pulmonary disease (COPD), and cystic fibrosis. They also include bronchopulmonary dysplasia, a respiratory disorder that causes breathing problems in pre-term newborns and can be a risk factor for respiratory conditions later in life.
Weakened or compromised immune system
When the immune system is not functioning at full capacity, a person is at a greater risk of any infection becoming more severe. This includes RSV. An immune system can also be weakened or compromised by chronic infections like HIV, and temporarily affected by medical treatments (like chemotherapy) or infection (such as the flu or mononucleosis).
Cardiovascular disease
Also called heart disease, cardiovascular disease refers to a group of conditions that affect the function of the heart, arteries, and blood vessels. High blood pressure, coronary artery disease, and heart failure are common cardiovascular conditions.
Unhealthy habits and lifestyle
Though they are not health conditions, habits like tobacco use, consuming excess amounts of alcohol, and eating an unhealthy diet can weaken the immune system and increase the risk of many chronic diseases.
It’s also important to note that RSV infections can make existing health conditions worse. COPD and heart failure may become more severe due to RSV infection, for example, or a person with asthma may experience more frequent flares.
Are you at risk for severe illness from RSV?
This is not a comprehensive list, and chronic conditions as well as viral infections like RSV can affect different people in different ways. The best way to understand your risk of severe illness caused by RSV (or other types of respiratory infections) is to talk to your healthcare provider.
How can you protect yourself from RSV?
Basic precautions like hand washing, avoiding contact with sick people, and minimizing exposure to crowded places during RSV season can help a person avoid becoming sick. RSV season typically begins in the fall and lasts through the spring, but it can vary depending on where you live. Patterns have also shifted in recent years and have become harder to predict.
You can also ask your healthcare provider about the RSV vaccine. Experts recommend vaccination for all adults ages 75 and older, as well as adults ages 50 to 74 who are at increased risk of severe disease. There are three vaccines for RSV approved by the U.S. Food & Drug Administration.
