Protecting your baby from RSV: What every parent needs to know

Having a sick baby can be a parent’s nightmare. Imagine your baby has been sick for a few days, and the pediatrician tells you it’s a viral infection that has no treatment other than supportive care. On the fourth day, you notice your baby using the muscles in his belly and chest to breathe, his mouth looks blue-tinged and, suddenly, you’re in the hospital with what started out as ‘just a cold.’

In adults under the age of 65 years and older children, respiratory syncytial virus (RSV) acts like any other highly contagious germ that can cause cold-like symptoms. However, RSV infections in young babies can be much more severe. Babies may develop bronchiolitis, which causes symptoms such as difficulty breathing, wheezing, dehydration, decreased oxygen levels, blue-tinged skin or even apnea (pauses in breathing lasting more than 10 seconds).

RSV is the most common cause of hospitalization for children under 1 year of age, and until last year, there was no way to prevent it. Statistics show that nearly 100% of children will be exposed to the RSV virus by age 2.

Fortunately, in fall 2023, the CDC recommended, and the FDA approved, an RSV shot for newborns. What do you need to know about the RSV shot (also known as nirsevimab or Beyfortus) for babies? First, it is not technically a vaccine. Vaccines use identifiers from a virus or bacteria to encourage our immune systems to work hard to protect us from that germ when we encounter it later. Our immune systems do this by making antibodies – small molecules that recognize parts of a virus or bacteria and then activate our immune system to attack that invader if they see it again. The baby RSV shot is made of those actual antibodies, rather than parts of viruses or bacteria. Because newborns have very immature immune systems, we are doing the work for them. Instead of teaching the body how to make antibodies, this injection gives babies the antibodies directly. This way, when your baby is exposed to RSV, they will already be prepared to fight against the dangerous virus.

Last season, the efficacy of the RSV shot in preventing RSV-associated bronchiolitis hospitalizations was an impressive 83%. 

The RSV shot is recommended for all infants under 8 months old entering their first RSV season (September-March). It also can be given to babies 8-19 months old entering their second RSV season if they are at increased risk of developing severe RSV symptoms (e.g., babies with chronic lung disease, cystic fibrosis, immunocompromised or those who are Alaskan Native or American Indian).

Last RSV season (2023), there were some shortages of the RSV shot for infants. However, this year, supply has increased, and it should be widely available. Newborns should receive the RSV shot before leaving the hospital after delivery. If it is unavailable there, they should receive it at their first visit with their pediatrician.

There is also another way to protect infants from severe RSV disease: a vaccine that the mother can get toward the end of her pregnancy. This allows the mother to produce antibodies, which she then passes down to her baby through the placenta. For more information about the maternal RSV vaccine, see this blog post.

With either the maternal vaccine given during pregnancy or the infant shot given right after birth, when your doctor tells you this RSV season that your baby’s symptoms are ‘just a cold’ that they will fight off on their own, they will be correct – because you have already given your baby the tools to fight against RSV.

As we continue to advance in the field of immunization, it is crucial for health policy to keep pace with scientific innovation. Ensuring equitable access to these life-saving treatments is not just a matter of public health, but also of medical ethics. Protecting the most vulnerable among us, especially infants, should remain at the forefront of our healthcare priorities. If you have any concerns or questions about RSV prevention, speak to your healthcare provider about the best options for your child.

By Drs. Dominique Davis, pediatric resident, and Lindy McGee assistant professor of pediatrics – academic general, Baylor College of Medicine