RS virus

What is the RS virus?

The RS virus is a predominantly winter virus that infects the respiratory tract, particularly the bronchial tubes and lungs. It is so contagious that almost all children will have been infected by the age of 2 years.
Immunity against the RS virus is strengthened by repetitive infections which will in turn decrease the severity of symptoms.
There is no test a doctor can do in the outpatient clinic to confirm infection. Diagnosis will mainly be made based on the patient’s age and symptoms.


Infants and young children get infected by airborne droplets or direct contact with patients. They will then suffer from a cough and fever as high as 38°C to 39°C. Most patients recover within 1 to 2 weeks. However, about 30% of patients will experience pneumonia and/or bronchiolitis or bronchitis with wheezing. Infants under 1 year of age need to be monitored carefully, especially children under 6 months who were born prematurely or have heart or lung problems, since their symptoms may worsen easily.


No antibiotics are effective against RS viral infections. Antibiotics may be prescribed only when there is the possibility of secondary bacterial infection.
In many cases, the best way to treat the disease is to alleviate symptoms. As with the common cold, monitoring the patients carefully while s/he stays in bed, keeps warm, takes plenty of fluids, gets a good sleep and eats well is the best prescription.
Prophylactic measures (antiviral immunoglobulin injections) are available during an outbreak of the virus for babies born prematurely (before 35 weeks) and who are aged between 6-12 months. Please ask your doctor about this.

When treating your child at home

Nourishment and fluids
Make sure your child gets plenty of fluids to prevent dehydration due to sweating. Don’t force your child to eat and only serve easily digestible food when s/he has an appetite.

Only when the fever has subsided.

Children can go back to school or nursery after their fever, cough and runny nose have subsided.

When to seek further medical advice

Hospitalization may be necessary when:
・Respiratory distress ( severe coughing, severe wheezing ) occurs
・Fluid intake becomes difficult
・The patient is lethargic from a high fever

Keiko Fukuyama M.D.