Ask the Experts: RSV (Respiratory Syncytial Virus): Disease Issues

Results (4)

Respiratory syncytial virus (RSV) is a common respiratory virus, usually causing mild, cold-like symptoms, such as cough, runny nose, sore throat, headache, fatigue, and fever. Though most people recover in a few days, for some people, RSV can cause serious lower respiratory tract infection (LRTI), such as bronchiolitis or pneumonia. RSV is the most common cause of hospitalization in infants in the United States. Older adults, especially those with chronic health conditions and those age 75 and older, are also more likely to develop severe RSV disease and need hospitalization. There is no specific treatment for RSV illness, only supportive care.

RSV causes annual outbreaks of respiratory illness in people of all ages. In the continental United States, RSV typically circulates in the fall and winter months, between October and March, although its seasonality can vary locally from year to year.

Last reviewed: August 25, 2024

Most adults experience a mild upper respiratory tract infection with RSV, with symptoms lasting only a few days. Some adults with RSV develop lower respiratory tract disease, including pneumonia. Because public health surveillance and testing for RSV in adults been limited in the past, our estimates of the burden of RSV disease are not precise and may underestimate the true burden among adults. Among U.S. adults age 65 and older, RSV is responsible for approximately 60,000 to 160,000 hospitalizations and 6,000 to 10,000 deaths each year.

The risk for severe RSV infection increases substantially with increasing age, especially among those who are 75 years of age and older. Risk is also increased for those who have one or more chronic health conditions, including people who are moderately or severely immunocompromised and people who are considered frail or who live in a nursing home or long-term care facility.  Among those with health conditions, the risk of hospitalization is goes up significantly with age and among those who have multiple health conditions. To review the specific high-risk conditions that ACIP considers important for vaccination of adults age 60 through 74 years, see this question.

Last reviewed: August 25, 2024

Almost all U.S. infants and toddlers contract RSV illness within the first two years of life. RSV causes a mild respiratory illness in most, with symptoms including cough, runny nose, fever, and fatigue. Illness is more likely to be mild if the child is older at the time of first infection. Infants with RSV infection frequently develop bronchiolitis, a lower respiratory tract disease (LRTD) that can be severe.

RSV LRTD is the leading cause of hospitalization among U.S. infants, who may require supplemental oxygen, treatment for dehydration, or mechanical ventilation. Approximately 50,000–80,000 RSV-associated hospitalizations and 100–300 RSV-associated deaths occur each year among U.S. infants and children younger than age 5 years. The risk of severe RSV disease is increased by prematurity and lung disease, among other health conditions. However, RSV is also the leading cause of hospitalization among healthy, full-term infants. The large majority (almost 80%) of infants and children younger than age 2 who are hospitalized with RSV are otherwise healthy and have no underlying medical conditions.

Some otherwise healthy American Indian or Alaska Native (AI/AN) children experience higher rates of severe RSV disease than the general population. One study found that the incidence of RSV-associated hospitalization among children in their second RSV season in some AI/AN communities was 4 to 10 times higher than that of similar-aged children elsewhere in the United States. AI/AN children living in remote areas also may have difficulty accessing adequate medical care when they develop LRTD.

Last reviewed: August 25, 2024

In most temperate regions of the continental United States and other areas with similar climates, RSV season typically begins in the fall and peaks in the winter, generally circulating between October and the end of March. However, the timing and severity of RSV season in a given community can vary from year to year. RSV seasonality was temporarily disrupted by the COVID-19 pandemic and widespread changes in social interactions and infection control practices (e.g., mask wearing, social distancing).

U.S. states and territories with very different weather patterns from the continental United States (e.g., Alaska, and areas with tropical weather patterns, such as Hawaii, southern Florida, Puerto Rico, and other island territories) may experience very different patterns of local RSV circulation. For this reason, public health authorities in those areas may issue different recommendations for appropriate timing of RSV prevention strategies (vaccines, monoclonal antibodies).

Last reviewed: August 25, 2024

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