Cases of respiratory syncytial virus (RSV) exploded in the U.S. last winter. At one point, more than 18 percent of tests for the virus came back positive, and hospitals admitted a number of babies and children with serious complications.[1] Now, there's good news for parents of little ones: The Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA) have endorsed an RSV antibody for babies and certain young children.[2]
"This is a big to-do," says Thomas Russo, M.D., professor and chief of infectious disease at the University at Buffalo in New York. The shot, called Beyfortus, is not a vaccine, but it can help prevent infection in infants. Here's what you need to know about it.
What is Beyfortus, the new RSV antibody?
RSV is a common respiratory virus that typically causes cold-like symptoms. Almost every child will get RSV by the age of 2. While most experience mild fever, cough and congestion, some develop dangerous and even deadly side effects, particularly premature infants and those with chronic lung disease or significant congenital heart disease.
Beyfortus (nirsevimab) is a drug that will help protect babies from this virus. The CDC now recommends that infants under 8 months born during or entering their first RSV season receive one dose. (RSV season typically starts in the fall and peaks in the winter.)[3] The group also advises children between 9 and 18 months old receive a dose if they're at increased risk of severe RSV disease.
The shot features monoclonal antibodies — lab-made proteins that mimic the immune system's ability to fight off pathogens like viruses.
"It's not a vaccine; it's a medication," explains Ian Michelow, M.D., division head of pediatric infectious diseases and immunology at Connecticut Children's Specialty Group. "It will recognize RSV in the body and fight infection."
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Vaccines typically give people part of a virus or bacteria and the body then makes antibodies in response. "In this case, we're giving pre-made monoclonal antibodies directly," Dr. Russo says. "It just skips a step."
Why is an RSV antibody for babies and toddlers a big deal?
RSV cases surged last year and caused a wave of hospitalizations in children. "RSV can cause very severe disease in children in large numbers," Dr. Michelow says.
There is no vaccine to protect children against RSV and, until this point, there wasn't an FDA-approved option like this for young children.
"Having something that can prevent RSV infection will significantly decrease hospitalizations and prevent deaths," Dr. Russo adds.
Is Beyfortus safe?
Beyfortus has gone through three clinical trials. "It has been shown to be safe and effective," says Amesh A. Adalja, M.D., a senior scholar at the Johns Hopkins Center for Health Security.
In one trial with 1,453 preterm infants, Beyfortus reduced the risk of contracting RSV by 70 percent compared to a placebo. In another trial with 1,490 babies born at or after 35 weeks, the medication lowered the risk by 75 percent.
The last trial featured children up to 24 months of age who were in their second RSV season and hadn't had the virus. It also provided safety evidence for infants with chronic lung disease or congenital heart disease.
What are the side effects of Beyfortus?
Beyfortus has a few potential side effects, per the FDA. Those include:
- Rash
- Reaction at the injection site
The drug also comes with warnings about potential serious allergic reactions, which have been observed in other monoclonal antibody treatments like this. The FDA also notes that the shot should be given "with caution" to infants and children who have clinically significant bleeding disorders.
When will Beyfortus become available?
The CDC's Advisory Committee on Immunization Practices (ACIP) says the drug should become available this fall.[4] Doctors hope that Beyfortus will arrive in clinics and offices as soon as possible.[5]
"This is an important tool that, coupled with vaccines for older adults, should make a major impact on the burden of RSV," Dr. Adalja says.
Dr. Michelow agrees: "From my perspective, the sooner it's available, the better."
FAQ
Who makes Beyfortus?
Pharmaceutical companies AstraZeneca and Sanofi developed Beyfortus.
What is the generic name for Beyfourtus?
The generic name for Beyfortus is nirsevimab.
When can newborns get Beyfortus?
The Centers for Disease Control and Prevention (CDC) says infants under 8 months can get Beyfortus as soon as this fall.
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