At a glance
Weekly updated estimates of outpatient visits, hospitalizations, and deaths caused by Respiratory Syncytial Virus (RSV) in the United States help us understand how RSV is impacting people’s health. These burden estimates are preliminary and based on weekly hospitalizations reported among persons with laboratory-confirmed RSV infections.
Importance of understanding RSV burden
RSV is a common respiratory virus that usually causes mild, cold-like symptoms. However, it can be dangerous for babies and older adults. In fact, for many in the United States each year, it can lead to illness, hospitalization, and sometimes, death. RSV is the leading cause of infant hospitalization in the United States.
Understanding the burden of RSV helps:
- Describe how infection is impacting people across the nation.
- Establish benchmarks to compare the burden associated with RSV year-over-year and with other respiratory viruses, like influenza and SARS CoV-2 (which causes COVID-19).
Why CDC estimates the burden of RSV
Fact
It is not possible to know the exact number of people who have experienced illness from RSV in the United States, because not everyone who contracts RSV will seek medical care or get tested for RSV. Because CDC surveillance (or tracking) systems will not identify all RSV illnesses, CDC uses continuously updated surveillance data, data from the latest scientific reports, and mathematical modeling to estimate the impact of RSV on the US population.
When sharing estimates of RSV disease burden, CDC provides a range around most likely values of RSV burden to better represent the uncertainty in the estimates.
CDC estimates the burden based on continuously collected surveillance data on patients hospitalized with laboratory-confirmed RSV. These data come from the Respiratory Syncytial Virus Hospitalization Surveillance Network (RSV-NET), a surveillance platform that captures data from hospitals that serve about 8% of the U.S. population.
Find more details on how RSV-NET data are used to estimate outpatient visits, hospitalizations, and deaths in the United States: How CDC Estimates Burden of RSV in the US.
Each week CDC estimates a range (i.e., lower estimate and an upper estimate) of RSV-associated hospitalizations that have occurred since the beginning of the season (October 1, 2024). This can help public health officials understand and plan for RSV-related impacts on healthcare systems and promote prevention measures.
Data are preliminary and estimates are subject to change as more data become available. Rates for recent RSV-associated hospital admissions are subject to reporting delays. As new data are received each week, previous rates are updated accordingly.
Current year RSV hospitalizations
Limitations of RSV burden estimates
Interpreting the cumulative burden of RSV
Preliminary burden estimates are provided weekly using data from October 1 of the current year when sufficient data are available to estimate the burden. The estimates are cumulative and will grow over time. End-of-season preliminary estimates are given after the end of the respiratory virus season. End-of-season preliminary estimates will be updated year-to-year and are considered final when all data for that season are available (usually within 2 years of the preliminary estimate).
The in-season cumulative estimates of RSV burden are preliminary and change week-by-week as updated RSV hospitalization data are reported to CDC via RSV-NET. Updated reports include both new admissions that have occurred during the reporting week and also patients admitted in previous weeks that may not have been included in earlier reporting to CDC.
It is important to note that these preliminary disease burden estimates reflect the overall burden that RSV has on the U.S. population. While older adults and young children are both at increased risk for severe RSV, they are affected very differently. RSV is the leading cause of infant hospitalization, but many fewer infants die from RSV compared to older adults.