Medication to Prevent RSV
A new medication is now available to help prevent respiratory syncytial virus (RSV) in babies. Just one shot can effectively keep your baby safe throughout their first RSV season - when they are most vulnerable to serious infection.
What is RSV?
Respiratory syncytial virus is a very common - and very contagious - illness. 7 out of 10 babies will get RSV before they turn one year old. Like the flu and other respiratory viruses, it spreads easily through the air when a sick person coughs or sneezes. It also spreads if they touch doorknobs, faucets or toys and then you touch it after them.
You can get RSV at any age. You can also get it repeatedly throughout your life. For most people, the symptoms are just like having a bad cold. However, for very young and very old people, RSV can be serious. Sometimes it will even require a hospital stay and help with extra oxygen or a ventilator (a machine that forces air into and out of a person's lungs). Each year, about 1 in 50 babies with RSV end up in the hospital. This can happen even to healthy, full-term babies. When older kids and adults get RSV, it mainly affects their ears, nose, and throat - like a head cold. But when babies get RSV, it also affects the tiny airways in their lungs. Those smaller airways (called bronchioles) can swell and produce extra mucus. This makes it very hard for a baby to breathe and breastfeed or use a bottle.
Families now have a safe and effective choice that helps prevent RSV in babies. The FDA approved a new RSV medication in 2023, nirsevimab (Beyfortus™).
Researchers tested nirsevimab in three separate clinical trials. In all three, they found it to be safe and effective. It lowered the risk of a hospital stay by up to 75 percent for full-term babies. The new medicine is similar to one that's been given to premature infants for many years - one with a proven safety record. That drug, called palivizumab, also helped prevent RSV. However, it required several monthly shots. This new medicine is only given one time.
Nirsevimab and monoclonal antibodies
When a healthy adult or older child is exposed to a virus (like one that causes a common cold), the body recognizes this virus as an invader. This triggers the immune system to make a special protein that will recognize and attack this virus. We call this protein an antibody. Nirsevimab (Beyfortus) is a medicine made of monoclonal antibodies. Monoclonal just means they are man-made, but they act just like the ones the body makes on its own.
Every day, people are exposed to many different types of infections. Fortunately, the immune system is always busy making new antibodies to fight off these infections. However, newborns do not yet have a good supply of antibodies. They may not have the ones they need to fight off RSV. The new RSV medicine gives a baby the antibodies they need to fight off RSV for up to five months. This medicine is not a vaccine – it is different. A baby cannot “catch” RSV from it.
Who should get Nirsevimab?
We recommend a single shot of nirsevimab for:
- All babies younger than 8 months born during or entering their first RSV season (usually October to March).
- Babies and young children ages 8 to 19 months with a high risk of severe RSV disease and who are entering their second RSV season.
This includes babies and children who:
- Are severely immune compromised
- Have severe, chronic lung disease
- Have cystic fibrosis
Frequently asked questions
There are currently two RSV vaccines — Arexvy™ and Abrysvo™. Both are FDA approved for adults over 60 years old. Abrysvo is also recommended for women who are 32 to 36 weeks pregnant. These are traditional vaccines that stimulate the immune system to recognize the RSV virus when it gets exposed. The vaccine helps prevent infection and limit the severity of symptoms if someone does get sick.
The monoclonal antibody shot for babies works differently. It provides antibodies that are already formed to protect your baby during their first RSV season. After that, your baby’s immune system should be able to produce its own antibodies to help them fight off future infection.
“All medications come with some risk of side effects, and nirsevimab is no different.,” says Dr. Phillips. “But overall, this medication is very well tolerated by babies.” In the clinical trials, only 1 percent of babies experienced any side effects, and those were mild. Most common was a slight rash or pain at the injection site.
If you’re concerned about side effects, talk to your pediatrician about the pros and cons of this medication for your baby.
The new immunization, nirsevimab, is very similar to an older medication that’s been used for years. Both are injections of pre-made antibodies to protect babies and children who can’t yet make their own. Nirsevimab is an improved, second-generation version of the original medication.
The biggest difference is how long the two medications protect against RSV. Palivizumab’s protection only lasts a month. So instead of a single shot of nirsevimab at the start of RSV season, babies would need monthly shots of palivizumab all winter.
We still use palivizumab in some cases — especially in children who are very vulnerable to severe RSV infection. Our pediatricians can help you decide which medication is right for your baby.
The new RSV medication is currently approved for babies 8 months and younger (with some exceptions for children with severe chronic illness). After living through an RSV season, most children will have built up their own antibodies to the infection. That protection means they no longer need the monoclonal antibodies they’d get from the injection.
If this is your baby’s first RSV season (or if they are born during RSV season), they should get the drug this year. A second shot next RSV season is recommended only for children who are vulnerable to severe RSV infection. This group includes children who are immune compromised or have serious lung disease or cystic fibrosis.