respiratory syncytial virus

noun

plural respiratory syncytial viruses

1

: a pneumovirus (Orthopneumovirus hominis) that usually causes mild infections of the upper respiratory tract and lungs, that is spread through contact with respiratory droplets, and that is characterized especially by fever, cough, congestion, and runny nose but may progress to bronchiolitis and pneumonia especially in infants, the elderly, and immunocompromised individuals

Respiratory viruses like COVID-19, influenza and respiratory syncytial virus often spread and peak during winter, when people travel for the holidays and spend more time indoors and breathing the same air.

—Jessica Rendall

Respiratory syncytial virus, or RSV, is a common respiratory virus that usually causes mild, cold-like symptoms in most people. … Infections typically go away on their own in a week or two.

—Ema Sasic

Note: Respiratory syncytial virus was initially identified in 1956 and was formerly classified as a paramyxovirus.

called also RSV

2

: the illness caused by respiratory syncytial virus

Symptoms of respiratory syncytial virus are comparable to those of a common cold and COVID-19. Symptoms include runny nose, fever, coughing, sneezing, decreased appetite and wheezing.

—Tyler Brown

An unseasonably early spike in respiratory syncytial virus cases among young children is pushing some hospitals to capacity.

—Vanessa Romo

called also RSV

Examples of respiratory syncytial virus in a Sentence

Recent Examples on the Web

Vaccines in the second group—those for at-risk populations—include vaccines for respiratory syncytial virus (RSV) and hepatitis A and B, and more, according to the executive order. — Jackie Flynn Mogensen, Scientific American, 10 Aug. 2026

Vaccines protecting against Hepatitis A, Hepatitis B, respiratory syncytial virus and meningitis groups A, B, C, W and Y are no longer universally recommended for all children. — Angela Rodriguez, Sacbee.com, 4 Aug. 2026

The vast majority of these pauses – about 90% – are related to data on vaccinations or impacts of common respiratory viruses, such as influenza, COVID-19 and respiratory syncytial virus, or RSV. — John Kubale, The Conversation, 8 July 2026

While at Johns Hopkins, Roizman and two colleagues discovered the respiratory syncytial virus, which infects lungs and the respiratory tract. — Bob Goldsborough, Chicago Tribune, 12 June 2026

Word History

First Known Use

1957, in the meaning defined at sense 1

Rhymes for respiratory syncytial virus

• adenovirus
• baculovirus
• coronavirus
• enterovirus
• poliovirus
• antivirus
• herpesvirus
• parvovirus
• reovirus
• retrovirus
• rhinovirus
• rotavirus

Medical Definition

respiratory syncytial virus

noun

1

: a pneumovirus (Orthopneumovirus hominis) that usually causes mild infections of the upper and lower respiratory tract, that is spread through contact with respiratory droplets, and that is characterized especially by fever, coughing, congestion, and runny nose but may progress to bronchiolitis and pneumonia especially in infants, the elderly, and immunocompromised individuals

Respiratory syncytial virus is the most important respiratory pathogen causing lower respiratory tract infection in infants and young children.

—David W. Smith et al., The New England Journal of Medicine

Note: Respiratory syncytial virus was initially identified in 1956 and was formerly classified as a paramyxovirus. Cells infected with the virus typically fuse with adjacent cells to form multinucleate syncytia.

called also RSV

2

: the illness caused by respiratory syncytial virus

… an expanding array of synthetic drugs is being clinically tested against many viral infections. … A handful already have been approved for medical use against herpes, influenza, and respiratory syncytial virus …, a common respiratory infection that usually is mild but can be life threatening to infants in poor health.

—Roland K. Robins, Chemical & Engineering News

called also RSV