RSV
Meaning of RSV: Nearly every child meets it in the first years of life, and one infection gives only partial protection, so reinfection continues through adulthood.
Definition of RSV
RSV stands for respiratory syncytial virus, a common virus that infects the airways. In most people it causes a cold, with a runny nose, cough and congestion, but in infants, older adults and those with weakened defenses it can reach the smaller airways and the lungs. It is named for the way infected cells fuse into large joined masses.
What does the name mean?
Respiratory describes where it acts, in the airways from the nose down to the smallest branches inside the lung. Syncytial describes what it does to cells: the virus makes neighboring infected cells merge their membranes, so many cells become one large mass carrying several nuclei, called a syncytium. That fusion was first seen in laboratory cultures and gave the virus its name. It also lets the virus pass from cell to cell without crossing the open space where antibodies would be waiting.
Who becomes seriously ill?
| Group | Why the risk is higher |
|---|---|
| Infants, especially in the first months | Very narrow airways block easily, and immune experience is limited |
| Babies born prematurely | Narrower airways still, and less antibody received before birth |
| Children with heart or lung conditions | Less reserve to absorb any extra load on breathing |
| Older adults | Immune responses weaken with age and other conditions are often present |
| People with weakened immunity | Infection lasts longer and reaches the lungs more readily |
In infants the characteristic illness is bronchiolitis, inflammation and blocking of the smallest airways, producing wheeze, fast breathing, drawing in of the chest wall with each breath, and difficulty feeding. RSV is the most common cause of it and a leading reason for admission to hospital in the first year of life, where respiratory therapy and supplemental oxygen support a child while the illness runs its course.
How does it spread, and how is it identified?
It passes in droplets from coughs and sneezes, and by touching a contaminated surface and then the face, and it survives on hard surfaces for hours. In temperate climates it arrives in seasonal waves through the colder months, while tropical regions see patterns tied to the rainy season. Infection leaves only partial and short lived immunity, so catching it again through life is normal and usually milder in healthy adults, where it looks like an ordinary cold and is rarely tested for. Because the symptoms overlap those of influenza, coronaviruses, other causes of respiratory tract infection and, in a coughing infant, whooping cough, telling them apart requires a laboratory test on a nose or throat swab, usually one detecting the virus's genetic material. Antibody products for infants and vaccines for older adults and for pregnancy have become available and are altering the pattern of severe illness.
Also known as
Used in a sentence
The infant tested positive for RSV after presenting with cough and difficulty feeding.
Good to know
RSV infection often begins looking like an ordinary cold but can extend into the lower airways, which is why infants, older adults and people with weakened immunity are watched more closely than the early symptoms alone would suggest.