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Respiratory Syncytial Virus RSV


Respiratory syncytial virus (RSV) is the most important global cause of viral acute lower respiratory tract illness (ALRI) in infants and children. In the United States, approximately 150,000 infants are hospitalized each year with RSV pneumonia or bronchiolitis (inflammation of the small airways), and up to 2 million children under the age of 5 receive medical care for RSV infection. Globally, RSV is estimated to cause up to 34 million cases of ALRI and up to 234,000 deaths in children each year.  The elderly are also at risk for severe RSV disease: up to 180,000 RSV-associated hospitalizations occur every year in elderly people in the United States.

The Center for Immunization Research has had a long-standing commitment to understanding the global epidemiology of RSV, to understanding how immune responses to RSV develop in young children, and to the development of safe and effective RSV vaccines to protect infants and young children.  Along with our colleagues at the Johns Hopkins Center for American Indian Health, we described very high rates of RSV hospitalization in Alaska Native and American Indian infants. We have recently described factors that may influence transplacental transfer of RSV antibody if a maternal RSV vaccine is developed, and are currently collaborating with colleagues to understand the interplay between RSV infections in early life, wheezing, and pulmonary function in school-aged children.

Much of our work in RSV vaccine development has focused on the clinical and labortory evaluation of live-attenuated RSV vaccines developed by our colleagues at the Laboratory of Infectious Diseases, NIAID, NIH. Recently, we described very promising results with the testing of a vaccine called RSV MEDI-DM2-2, which used recombinant technology to ‘outwit’ the virus and strike the right balance between attenuation (weakening the virus so it doesn’t make children sick) and immunogenicity (eliciting an immune response that will be protective).

In 2023, two major advancements in RSV treatment and prevention were approved by the FDA. In May, they approved Arexvy for people 60 years old and older.  Arexvy is the first RSV vaccine approved for use in the United States. In July, they approved Beyfortus (nirsevimab-alip) for the prevention of RSV lower respiratory tract disease in neonates and infants born during or entering their first RSV season, and in children up to 24 months of age.