Adults can get RSV, and its severity depends on a number of factors, including a person’s age, medical history, and overall health.

Many people believe that respiratory syncytial virus (RSV) affects only young children. But adults can get RSV as well, and some may become seriously ill as a result.

In this article, we take a closer look at RSV in adults, including who is at risk for severe illness and what you can expect if you get sick.

After young children, older adults — that is, people ages 65 and over — are most likely to experience severe complications from RSV.

According to the Centers for Disease Control and Prevention (CDC), an estimated 60,000 to 160,000 older adults are hospitalized after contracting RSV each year in the United States. Of those, approximately 6,000 to 10,000 die due to RSV-associated illness.

Most people have had RSV at some point in their life, likely even multiple times. Some studies have estimated that approximately 7-20% of adults contract RSV each year. Other studies looked at in a 2022 research review suggest that this percentage likely underestimates the true frequency of RSV in adults.

That’s because unless you get very sick from RSV, you may not know you have it.

In most people, the virus causes mild cold-like symptoms. It’s hard to tell them apart from other respiratory illnesses. The only way to diagnose RSV is by testing for the virus, which isn’t usually done unless a person is very young or has severe symptoms.

Without comprehensive testing of everyone with respiratory symptoms, it’s difficult to estimate the true frequency of RSV in adults.

Why are older adults at risk?

Older adults may be at higher risk of contracting RSV or developing severe illness due to RSV because the immune system weakens with age. Our bodies don’t respond as well to viruses, which means we can experience more serious symptoms if we get RSV.

This is known as immunosenescence, and it leaves older adults at risk of more severe complications from RSV.

Older adults may also be more likely to have underlying health conditions that increase the likelihood of severe illness.

In addition to older age, certain medical conditions can put adults at increased risk of severe RSV infection.

Chronic lung conditions

People with chronic lung conditions, such as asthma or chronic obstructive pulmonary disease (COPD), may have a worsening of their symptoms if they contract RSV. The virus can cause tissue damage and inflammation in the lungs, which can affect lung function.

This can lead to asthma attacks or COPD exacerbations that put additional strain on the lungs and make RSV symptoms more severe.

A study from 2005 found that RSV infections are responsible for more than 7% of hospitalizations due to asthma and 11.4% of hospitalization due to COPD in high risk adults.

Chronic heart conditions

Chronic heart conditions such as congestive heart failure and coronary artery disease can also increase the likelihood of developing severe complications from RSV.

Estimates vary widely, but most studies suggest that between 20% to 50% of people who are hospitalized with RSV also have some form of underlying heart disease. In a recent study examining RSV hospitalization records from 2015 to 2017, people with congestive heart failure were more than eight times as likely to be hospitalized for RSV illness than those without the condition.

The risk for severe complications in people with heart disease is likely the result of a combination of general inflammation and compromised lung function, which can put stress on the heart.

In rare cases, these effects may even cause new heart complications in otherwise healthy adults.

Weakened immune system

A weakened immune system isn’t just the result of age. A variety of medical conditions can weaken the immune system and increase the likelihood of severe illness from RSV.

Some examples of conditions that weaken the immune system include:

  • pregnancy
  • blood cancers, such as leukemias, lymphomas, or multiple myeloma
  • HIV infection
  • treatment with immunosuppressive medications

Most people with RSV infection will experience mild, cold-like symptoms, such as a runny nose, fever, and cough. Some may have less appetite than usual. Wheezing is another common symptom.

Symptoms typically start within 4 to 6 days after exposure and resolve on their own in 1 to 2 weeks.

People who have severe RSV symptoms may develop additional health problems, including bronchitis or pneumonia. For people with underlying medical heart and lung conditions, the symptoms of those conditions may worsen.

A typical case of RSV gets better on its own, without treatment. You can help relieve symptoms by drinking fluids (water, juice, broth-based soups), using over-the-counter fever and pain reducers (such as acetaminophen or ibuprofen) as needed, and getting plenty of rest.

Mild RSV is often also treated with antitussives, decongestants, nasal sprays, and inhalers.

If more severe symptoms develop, reach out to your healthcare professional or seek emergency medical care. There is no treatment for RSV infection, but supportive care — including intravenous fluids, nebulizer treatments, and oxygen — can be provided. In very severe cases, intubation may be needed to support breathing.

In most cases, symptoms of RSV infection improve within 1 to 2 weeks.

When hospitalization is required to treat RSV, the in-patient care usually lasts no more than a few days. One 2022 study found that the average length of hospitalization for RSV-associated illness was 4.5 days.

If you or a loved one is at high risk for severe illness from RSV infection, the most effective way to prevent complications is to try to stay healthy. Avoid close contact with people who have symptoms or a confirmed diagnosis, wash your hands and surfaces in your home regularly with soap and water, and avoid touching your face.

You should also cover your mouth fully when you cough and sneeze, especially in the presence of people in at-risk groups. Stay home when you are sick or experiencing cold-like symptoms, and avoid sharing food and drinks with people who have a higher risk.

If you have an infant who is considered high risk for severe illness due to underlying heart or lung conditions, their doctor may consider giving them Palivizumab, an injectable medication that can help prevent RSV infection.

Seek emergency medical care if you begin showing signs of severe respiratory illness. This includes:

  • shortness of breath
  • fever
  • bluish tint to skin
  • wheezing
  • worsening cough

These may be signs of severe complications from RSV infection, such as bronchitis, pneumonia, or worsening of heart and lung conditions.

Most adults who contract RSV will experience a mild illness with cold-like symptoms that get better on their own within a couple of weeks. For others, though, severe complications can develop that may require hospitalization.

If you are an older adult or if you have an underlying medical condition that increases the likelihood of severe RSV infection, knowing the signs and symptoms of severe respiratory illness can help ensure you get the medical care you need in a timely manner.