Respiratory syncytial (sin-SISH-uhl) virus, or RSV, is a common respiratory virus that usually causes mild, cold-like symptoms. Most people recover in a week or two, but RSV can be serious, especially for infants, older adults and those with weakened immune systems. RSV is the most common cause of bronchiolitis (inflammation of the small airways in the lung) and pneumonia (infection of the lungs) in children younger than 1 year of age in the United States. RSV circulation in the United States usually starts during fall and peaks in the winter. The timing and severity of RSV circulation can vary from year to year.
In most people, RSV causes a mild, cold-like illness that lasts for 1-2 weeks. Symptoms usually appear 4 to 6 days after getting infected. Symptoms of RSV infection usually include:
- Runny Nose
Symptoms usually appear in stages and not all at once. In very young infants
with RSV, the only
symptoms may be:
your healthcare provider
right away if you or your child is having difficulty breathing, not drinking enough fluids, or
your symptoms are
Care for RSV
Most RSV infections go away on their own in a week or two. There is no specific treatment for RSV infection, but you can take the following steps to relieve symptoms:
- Manage fever and pain with over-the-counter fever reducers and pain relievers, such as acetaminophen or ibuprofen.
- Drink enough fluids to prevent dehydration (loss of body fluids).
- Talk to your healthcare provider before giving your child nonprescription cold medicines. Some medicines contain ingredients that are not good for children.
People at Risk for
Occasionally, RSV infection can cause lower respiratory infections like bronchiolitis and pneumonia. RSV infection can also sometimes lead to exacerbations of chronic health conditions such as asthma, chronic obstructive pulmonary disease (COPD) or congestive heart failure. People most at risk of serious illness from RSV infection include:
- Young children with congenital (from birth) heart or chronic lung disease
- Young children with weakened immune systems due to a medical condition or medical treatment
- Children with neuromuscular disorders
weakened immune systems
- Older adults, especially those with underlying heart or lung disease
People infected with RSV are usually contagious for 3 to 8 days and may become contagious a day or two before they start showing
symptoms. Some infants,
and people with weakened
immune systems, can
continue to spread the
virus even after they
stop showing symptoms,
for as long as 4 weeks.
RSV can spread when:
- An infected person coughs or sneezes
- Virus droplets from a cough or sneeze
get in your eyes, nose, or mouth
has direct contact with the virus, like kissing the face of a child with RSV
it and then touches
usually lives on soft surfaces such as tissues and hands for
a shorter amount of time.
The following are
steps that can be taken
to prevent the spread of
- Wash your hands often with soap and water for at least 20 seconds
- Avoid close contact, such as kissing
and shaking hands with others
home from work or school when sick, until symptoms improve
- Avoid sharing cups and eating utensils with others
- Clean frequently touched surfaces
Vaccines and vaccine-like products:
There are several
safe and effective
for infants, seniors,
and pregnant women.
These products can
prevent severe RSV
disease in infants and
older adults. Although
these products are
highly effective at
disease, they are not
fully protective against
all RSV infections so
people who are high risk
should continue to take
the above prevention
precautions in addition
to receiving these
Older Adults (60
years and older)
- One dose of nirsevimab, a long acting monoclonal antibody, is recommended for infants younger than 8 months of age who were born shortly before or are entering their first RSV season (typically October 1 through March 31st) to protect them from RSV disease during the first 5 months of life. This includes infants in the following situations:
- The mother did not receive RSV vaccine during pregnancy.
- The motherís RSV vaccination status is unknown.
- The infant was born within 14 days of maternal RSV vaccination.
- lnfants should receive nirsevimab starting in October through the end of March.
- Additionally, infants and children 8-19 months of age who are at increased risk for severe RSV disease and entering their second RSV season should receive also receive a dose of nirsevimab. This includes:
- American Indian/Alaska Native children.
- Children with chronic lung disease of prematurity who require medical support during the six months before the start of their second RSV season.
- Children with severe immunocompromise.
- Children with severe cystic fibrosis.
- Pregnant persons should be offered RSV vaccine between September and January during weeks 32 through 36 of pregnancy. This vaccine will protect infants from RSV infection during the first 6 months of life.
- To prevent severe RSV disease in infants, either maternal RSV vaccination or Nirsevimab is recommended. Most infants will not need both.
Individual cases of
RSV are not currently
reportable to LACDPH.
Data tracking RSV trends
in Los Angeles County
are available in the
latest issue of
News and Updates
LAC DPH Health Advisory:
Immunize Infants and Older Adults to Protect them from Severe RSV (9-6-23)
CDC Health Advisory:
Increased Respiratory Virus Activity, Especially Among Children, Early in the 2022-2023 Fall and Winter