Every year, one to three percent of children are hospitalized for RSV, according to the American Academy of Pediatrics. In a turn of events, the FDA has just approved a monoclonal antibody (nirsevimab or Beyfortus), which is a synthetic injectable protein produced by AstraZeneca, that fights respiratory syncytial virus (RSV). RSV is a very common cause of lower respiratory tract infections in children under 2 years of age. It typically causes fever and wheezing, but sometimes it causes severe complications in very young children and immunocompromised people of all ages.

This decision comes soon after last fall’s nationwide RSV surge and offers hope particularly for the most vulnerable newborns and infants who are born prematurely, develop long-term lung disorders complicating prematurity, and those born with heart defects. As we approach flu and RSV season, it’s important for us to help families take every precaution possible. Naturally, parents have questions about the new, FDA approved drug for RSV. Connecticut Children’s Dr. Ian C. Michelow, has answers…

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Who will qualify for the drug, once available to the public?

Clinical trials showed that both premature and term newborns benefitted from the new treatment. The FDA proposed that the antibodies be used for newborns and infants born during or entering their first RSV season, as well as children up to 2 years of age who remain vulnerable to severe RSV disease through their second RSV season.

What is the difference between a monoclonal antibody and a vaccine?

While both vaccines and monoclonal antibodies are injections that prevent infections, there is an important difference. Monoclonal antibodies are preformed, human-made immune proteins that are injected into people and they are ready to fight infections if needed, but they don’t last very long. Vaccines are typically made from fragments of infectious agents that, once injected, “train” your immune system to build natural, longer-lasting defenses that are ready to fight infections whenever needed.  

How long will protection from the RSV monoclonal antibody last?

Nirsevimab (Beyfortus) was created to offer protection throughout the duration of RSV season.

Hasn’t there already been an RSV shot for newborns?

There has never been a safe and effective RSV vaccine. There is another monoclonal antibody called palivizumab or Synagis, but that is only used for high risk premature infants or other young infants with certain types of heart disease.

How safe and effective is the new RSV monoclonal antibody?

Very safe and very effective. The evidence is supported by three clinical trials, all of which you can read about on the FDA website.

What are some possible side effects of the new RSV drug?

The most common side effects are rash and irritation where the shot was given. But in the clinical trials, the side effects were similar to those who received the mock treatment.

When will the new RSV drug become available to my child?

Now that the FDA has approved the medication, the CDC will weigh in on the specific recommendations for use in children, which expect to take place in August 2023. It will likely be available this fall.