Respiratory Syncytial Virus-Associated Mortality (RSV-Associated Mortality)
2019 Case Definition

Background

Over 57,000 hospitalizations, 500,000 emergency department visits and 1.5 million outpatient clinic visits among children <5 years of age are attributed to respiratory syncytial virus (RSV) infections each year in the United States. RSV-associated deaths among children <5 years of age are thought to be uncommon, estimated at 100-500 per year. Among US adults, an estimated 177,000 hospitalizations and 14,000 deaths associated with RSV infections occur annually. However, these are likely underestimates of RSV-associated deaths. In recent years, laboratory testing for RSV has increased in availability and practice. A more accurate assessment of RSV-associated deaths is important for establishing a baseline level of mortality ahead of the potential licensures of vaccines, immunoprophylaxis products, and anti-viral therapies. Additionally, a better understanding about who is at risk of RSV-associated deaths may help identify populations to target for interventions.

Clinical Criteria

A respiratory syncytial virus (RSV)-associated death is defined for surveillance purposes as a death resulting from a clinically compatible illness that was confirmed to be RSV by an appropriate laboratory or rapid diagnostic test. There should be no period of complete recovery between the illness and death.

A death should not be categorized as an RSV-associated death if:

• There is no laboratory confirmation of RSV infection.
• The RSV illness is followed by full recovery to baseline health status prior to death.
• After review and consultation, it is determined that RSV infection did not contribute to death.

Laboratory Criteria For Diagnosis

Confirmatory laboratory evidence:

Laboratory testing for respiratory syncytial virus infection may be done on pre- or post-mortem clinical specimens, and include identification of RSV (A, B, or unspecified) infection by a positive result by at least one of the following:

1. Isolation of respiratory syncytial virus by tissue cell culture
2. Detection of respiratory syncytial virus nucleic acid by reverse-transcriptase polymerase chain reaction (RT-PCR) or other nucleic acid detection assay
3. Detection of respiratory syncytial virus antigen by immunofluorescent antibody staining (direct or indirect)
4. Detection of respiratory syncytial virus antigens by immunochromatographic or similar rapid laboratory test
5. Detection of respiratory syncytial virus antigens from autopsy specimens by immunohistochemical (IHC) staining

Confirmed

A death meeting the clinical and laboratory criteria.