RSV Infection: Symptoms, Causes, How It Spreads, and When to Seek Medical Care

Quick Overview

Respiratory syncytial virus (RSV) is a common respiratory virus that infects the lungs and airways. It affects people of all ages. In many adults and older children, RSV causes mild, cold-like symptoms. In some infants, older adults, and people with certain medical conditions, RSV can lead to more serious lower respiratory tract illness, including bronchiolitis or pneumonia.

RSV spreads easily from person to person through respiratory droplets and contact with contaminated surfaces. Most infections improve on their own, but severe cases may require hospital care.

Note: Some commonly searched questions do not have high-quality evidence in the sources used for this article. Those answers are clearly labeled.

What Is RSV?

RSV (respiratory syncytial virus) is a virus that causes respiratory infections. Nearly all children are infected at least once by age two, and people can be infected multiple times throughout life. Immunity after infection is not long-lasting.

How RSV Spreads

RSV spreads through:

• Respiratory droplets when an infected person coughs or sneezes
• Direct contact, such as hand-to-hand contact with someone who has RSV
• Contaminated surfaces, followed by touching the eyes, nose, or mouth

The virus can survive for several hours on hard surfaces like countertops, toys, or crib rails.

People are usually most contagious during the first week after infection. Infants and people with weakened immune systems may continue to spread RSV for several weeks after symptoms improve.

Who Is at Higher Risk for Severe RSV?

Some groups are more likely to develop severe illness, including:

• Infants, especially those born prematurely or very young
• Older adults, particularly those age 65 and older
• People with chronic heart or lung disease
• People with weakened immune systems

Additional risk factors:
Children under two are especially susceptible, and almost all children will have been infected with RSV by age two—often more than once. The risk is even higher for infants who attend child care or have school-aged siblings, as exposure increases in group settings. Babies with congenital heart disease, chronic lung disease, or neuromuscular disorders (like muscular dystrophy) are at greater risk for complications.

Adults aren’t immune to serious infection either: those with heart or lung disease, weakened immune systems (from illnesses like cancer or treatments such as chemotherapy), and older adults—especially age 65 and up—should be especially cautious during RSV season, which typically lasts from fall through spring.

How Tobacco Smoke Affects RSV Risk in Infants

Exposure to tobacco smoke increases the risk of RSV infection and can make symptoms more severe, especially in babies. Secondhand smoke irritates the airways and weakens the immune system, making infants more vulnerable to respiratory infections like RSV. If you smoke, it’s safest to avoid doing so anywhere near your child—including inside your home or car—to help reduce their chances of getting sick.

RSV Symptoms

Common Symptoms (Often Mild)

In adults and older children, RSV symptoms often resemble a common cold and may include:

• Runny or congested nose
• Cough
• Low-grade fever
• Sore throat
• Sneezing
• Headache

Symptoms in Infants and Young Children

Infants may become more seriously ill. Symptoms can include:

• Rapid, short, or shallow breathing
• Chest muscles pulling inward during breathing (retractions)
• Poor feeding
• Unusual sleepiness (lethargy)
• Irritability
• Cough

Severe RSV Symptoms

RSV can spread to the lower respiratory tract and cause bronchiolitis or pneumonia. Signs of severe illness may include:

• Wheezing
• Rapid or difficult breathing
• Bluish color of the lips or skin (cyanosis), indicating low oxygen
• Fever with worsening respiratory symptoms

Severe RSV may require hospitalization, especially in high-risk individuals.

Complications from RSV can be serious, particularly for infants, young children, older adults, and those with weakened immune systems or chronic heart or lung conditions. Possible complications include:

• Hospitalization: Severe cases may require a hospital stay for oxygen support, monitoring of breathing, or intravenous (IV) fluids.
• Pneumonia: RSV is a leading cause of pneumonia and bronchiolitis in infants, but these complications can also affect older adults and people with underlying health issues.
• Middle ear infections (otitis media): Children, especially infants, can develop ear infections if the virus spreads to the space behind the eardrum.
• Asthma risk: Severe RSV in childhood may increase the chance of developing asthma later in life.
• Repeated infections: RSV does not provide lasting immunity. Reinfections are common—even within the same season—and while they’re often milder, they can still be severe in vulnerable groups.

If you notice severe symptoms—such as difficulty breathing, persistent high fever, blue-tinged lips or skin, or dehydration—seek medical attention promptly.

How Long RSV Lasts

Most people recover within one to two weeks. A cough may linger longer. Severe cases may take longer to resolve.

How RSV Is Diagnosed

Healthcare providers may diagnose RSV based on symptoms and physical examination. In some cases—particularly in people with severe illness—testing of respiratory samples and imaging studies may be used.

RSV Treatment

There is no specific cure for RSV infection in routine cases. Treatment focuses on supportive care, which may include:

• Rest
• Fluids to prevent dehydration
• Symptom relief as recommended by a healthcare provider

People with severe RSV may require hospital care, including:

• Supplemental oxygen
• Intravenous (IV) fluids
• Additional respiratory support, depending on severity

Antibiotics do not treat RSV unless a secondary bacterial infection is present.

How to Help Prevent RSV

Prevention strategies include:

• Washing hands frequently
• Avoiding close contact with people who have respiratory symptoms
• Cleaning and disinfecting frequently touched surfaces
• Avoiding sharing cups, utensils, or drinking glasses when someone is sick
• Covering coughs and sneezes

Additional steps can further reduce the risk of RSV:

• Teach children to wash their hands thoroughly and regularly.
• Keep kitchen and bathroom surfaces, doorknobs, and handles clean, especially during cold and flu season.
• Dispose of used tissues promptly in the trash.
• Use individual or disposable cups when someone in the household is ill, and label each person’s cup to prevent mix-ups.
• Do not smoke, as exposure to tobacco smoke increases the risk and severity of RSV—never smoke inside the home or car.
• Wash toys often, especially if your child or their playmates have been sick.

Vaccines and preventive antibody products are available for certain groups, including older adults, pregnant individuals, and some infants and young children.

Vaccines and preventive antibody products are available for certain groups, including older adults, pregnant individuals, and some infants and young children.

When to See a Doctor

Seek Medical Evaluation If:

• Symptoms are worsening or not improving
• There are signs of dehydration
• Wheezing or breathing difficulty develops
• A high-risk person becomes sicker

Seek Emergency Care Immediately If:

• There is significant difficulty breathing
• Skin, lips, or nail beds appear blue or gray
• An infant has pauses in breathing
• Breathing is very labored or rapid

RSV and Other Respiratory Viruses

RSV symptoms can overlap with other respiratory infections, including COVID-19. In children, both RSV and COVID-19 may cause mild symptoms such as fever, runny nose, and cough. In adults, COVID-19 symptoms can be more severe and include trouble breathing. RSV and COVID-19 infections can occur together, and co-infection may increase illness severity. Additionally, having RSV may lower immunity, potentially raising the risk of contracting COVID-19 for both kids and adults. When these infections happen at the same time, they can make COVID-19 illness worse.

There is no high-quality evidence confirming symptom overlap between RSV and influenza in the sources reviewed.

Can RSV Lead to Asthma Later in Life?

Research suggests that children who experience severe RSV infection, particularly in infancy, may have a higher risk of developing asthma as they grow older. While the connection is not fully understood, studies indicate that serious RSV illness could play a role in the development of long-term respiratory issues such as asthma. However, not every child who gets RSV will develop asthma, and other factors—like genetics and environment—also influence asthma risk.

Frequently Asked Questions

APA References List

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Centers for Disease Control and Prevention. (2025, July 7). RSV in adults. https://www.cdc.gov/rsv/adults/index.html

Centers for Disease Control and Prevention. (2025, July 8). How RSV spreads. https://www.cdc.gov/rsv/causes/index.html

Centers for Disease Control and Prevention. (2025, July 8). Symptoms and care of RSV. https://www.cdc.gov/rsv/symptoms/index.html

Centers for Disease Control and Prevention. (2024, August 30). RSV vaccine guidance for pregnant women. https://www.cdc.gov/rsv/hcp/vaccine-clinical-guidance/pregnant-people.html

Centers for Disease Control and Prevention. (2025, August 14). Healthcare providers: RSV immunization for infants and young children. https://www.cdc.gov/vaccines/vpd/rsv/hcp/child.html

Centers for Disease Control and Prevention. (2025, August 18). Immunizations to protect infants. https://www.cdc.gov/rsv/vaccines/protect-infants.html

Centers for Disease Control and Prevention. (2025, August 18). RSV immunization guidance for infants and young children. https://www.cdc.gov/rsv/hcp/vaccine-clinical-guidance/infants-young-children.html

Centers for Disease Control and Prevention. (2025, August 18). Hygiene and respiratory viruses prevention. https://www.cdc.gov/respiratory-viruses/prevention/hygiene.html

Cleveland Clinic. (2025, May 7). RSV (respiratory syncytial virus). https://my.clevelandclinic.org/health/diseases/rsv-respiratory-syncytial-virus

International Committee on Taxonomy of Viruses. (n.d.). Family: Pneumoviridae. https://ictv.global/report/chapter/pneumoviridae/pneumoviridae

International Committee on Taxonomy of Viruses. (n.d.). Genus: Orthopneumovirus. https://ictv.global/report/chapter/pneumoviridae/pneumoviridae/orthopneumovirus

Jones, J. M., Fleming-Dutra, K. E., Prill, M. M., et al. (2023). Use of nirsevimab for the prevention of respiratory syncytial virus disease among infants and young children: Recommendations of the Advisory Committee on Immunization Practices—United States, 2023. MMWR Morbidity and Mortality Weekly Report, 72. https://www.restoredcdc.org/www.cdc.gov/mmwr/volumes/72/wr/mm7234a4.htm

Mayo Clinic Staff. (2023, October 4). Respiratory syncytial virus (RSV): Symptoms & causes. https://www.mayoclinic.org/diseases-conditions/respiratory-syncytial-virus/symptoms-causes/syc-20353098

MedlinePlus. (n.d.). Respiratory syncytial virus infections. National Library of Medicine. https://medlineplus.gov/respiratorysyncytialvirusinfections.html