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
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.
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
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. RSV and COVID-19 infections can occur together, and co-infection may increase illness severity.
There is no high-quality evidence confirming symptom overlap between RSV and influenza in the sources reviewed.
Frequently Asked Questions
How quickly does RSV spread?
RSV spreads easily through close contact and respiratory droplets. People can transmit RSV before they realize they are sick.
Is RSV contagious?
Yes. RSV spreads easily from person to person.
Can RSV be asymptomatic?
There is no high-quality evidence available confirming asymptomatic RSV infection.
Does RSV cause high fever?
Fever can occur with RSV, including in severe cases. Evidence does not support defining RSV by high fever alone.
When should I take a baby to the emergency room for RSV?
Emergency care is needed if an infant has severe breathing difficulty, pauses in breathing, bluish skin color, or significant feeding problems with respiratory distress.
How is RSV spread?
RSV spreads through respiratory droplets, direct contact, and contaminated surfaces.
How long is RSV contagious?
Most people are contagious for about a week. Infants and immunocompromised individuals may remain contagious for several weeks.
What are RSV symptoms in toddlers?
There is no high-quality evidence available describing toddler-specific symptoms distinct from general childhood RSV symptoms.
When should I go to the ER for RSV?
Emergency care is needed for severe breathing problems, cyanosis, or other signs of serious illness.
What does “orthopneumovirus” mean?
RSV is classified in the genus Orthopneumovirus. This classification is scientific and does not change how RSV is treated or managed clinically.
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
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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