What’s Beyfortus, the brand new RSV preventative medication for infants and toddlers?


Each year, respiratory syncytial virus (RSV) sends up to 80,000 children under the age of five to hospital; for hundreds of these children, the complications caused by the virus are deadly. Various RSV vaccines have recently been approved for the elderly, but we don’t have a reliable way to protect children from serious illness caused by the virus, especially during cold and flu season when other bugs are also floating around.

That could change this fall and winter. On July 17, the United States Food and Drug Administration (FDA) approved a new RSV preventive medication, Beyfortus (nirsevimab-alip), for babies and children up to two years of age.

« [This medication] will save lives and keep vulnerable children out of hospital,” Mark Hicar, MD, Ph.D.pediatric infectious disease specialist and associate professor of pediatric medicine at the University at Buffalo in New York, says SELF.

Almost all children will get RSV before the age of two, and many have a mild illness characterized by cold-like symptoms. But the virus can be very risky for some children, the FDA notes, including babies born prematurely and those with chronic lung or heart conditions.

“RSV is the leading cause of infant hospitalizations in the United States,” William Schaffner, MD, an infectious disease specialist and professor of medicine at Vanderbilt University School of Medicine in Nashville, tells SELF. When children become seriously ill of the virus, they can develop pneumonia (an infection of the lungs) or bronchiolitis (inflammation of the small airways of the lungs), which can lead to symptoms like rapid abdominal breathing or wheezing.

After last year’s intense cold and flu season, during which COVID-19, RSV and influenza circulated and overwhelmed many hospitals— the approval of this new drug is good news, especially for parents, according to the experts we spoke to. Here’s what you need to know about Beyfortus, including how it works, how effective it is, and when it’s available.

Beyfortus works a little differently than a vaccine.

Beyfortus, jointly developed by Sanofi and AstraZeneca, is a monoclonal antibody administered in a single injection. « Monoclonal » refers to lab-created versions of antibodies, the proteins your immune system produces to fight off foreign substances that enter the body, including harmful substances like viruses, the FDA explains.

This medicine is particularly aimed at preventing RSV in babies born during « RSV season » (i.e. cold and flu season) or in children entering their first RSV season, as well as children under two years of age who are vulnerable.

An injection to prevent an infectious disease sounds a bit like a vaccine, but it’s not in this case. « Vaccines stimulate the body’s immune system to produce antibodies, which can, in some vaccines, provide lifelong protection, » Rosey Olivero, MDthe pediatric infectious disease section chief at Helen DeVos Children’s Hospital in Grand Rapids, Michigan, tells SELF.

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