What is RSV and Why Immunize?
Respiratory syncytial virus (RSV) is a germ that spreads by droplets from the nose and mouth while coughing or sneezing. It generally starts in the fall, peaks in the winter, and ends for the most part in the spring. Anyone can get RSV. An overwhelming majority of infants will develop their first RSV infection by 1 year of life and almost all by age 2.
Most infants and children infected with RSV develop cold like symptoms including fever, nasal congestion, runny nose, and cough that typically resolve after a week or two. In some, the virus spreads into the chest affecting the small branches of the bronchial tubes (bronchiolitis), the lungs (pneumonia) or both. Symptoms at that time may be mild manifested as audible wheezing, worsening cough, increased respiratory rate and mild to no respiratory distress to more severe involvement resulting in an inability to safely feed, a marked increase in the rate of breathing and moderate to severe respiratory distress. Such patients may develop dehydration or low oxygen levels in their bodies requiring IV fluids and supplemental oxygen in the hospital. The sickest of patients may require the breathing assistance of a ventilator.
Each year in the United States, RSV leads to millions of outpatient (clinic or ER) visits per year and tens of thousands of hospitalizations.
Approximately 2% of all infants require hospitalization for an RSV infection during the first year of life. Underlying health conditions, especially premature birth, chronic lung disease, and congenital heart disease, predispose children to severe RSV illness however 80% of hospitalized infants do not have any risk factors.
Severe RSV infection risk can be dramatically reduced by providing at risk infants with protective RSV antibodies. Antibodies are proteins that the body’s immune system uses to fight off harmful germs. Like traditional vaccines, preventive antibodies are immunizations that provide protection against a specific germ. While both are immunizations, the way they provide immunity is different. RSV antibodies can be given directly to a patient. Once in the body, the antibodies provide immediate protection against RSV. Traditional vaccines are immunizations that stimulate the recipient’s immune system to produce antibodies. This process takes time and may not be complete. Currently no vaccine is available against RSV for infants. An RSV vaccine is available for pregnant women. This vaccine should be administered at 32-36 weeks of pregnancy. After a couple of weeks, the mother’s immune system makes antibodies against RSV that are passed through the placenta into the infant’s body. If given within 2 weeks of birth, most infants will be protected against serious RSV disease and do not require additional immunization.
Preventing Severe RSV Disease
For over 2 decades, high risk patients have been given monthly injections of RSV antibodies through the RSV season. The process was fairly involved and rather expensive. This year a new RSV antibody immunization was approved (generic name nirsevimab, trade name Beyfortus). These antibodies are more stable in the body with one injection providing protection for the entire RSV season thereby significantly reducing logistical challenges and the cost as well. Beyfortus has been shown to reduce the risk of hospitalization secondary to severe RSV disease by 80%.
The centers for disease control (CDC) and the American Academy of Pediatrics (AAP) universally recommend that infants born during the RSV season should receive a single dose of the RSV Immunization within 1 week after birth.
Infants born outside of the RSV season who are younger than 8 months should receive a single dose of the RSV Immunization shortly before their first RSV season (in October), but infants who are younger than 8 months who have not yet received a dose may receive a dose at any time during the season.
Some infants and young children who are at increased risk for severe RSV disease may need a single dose of the RSV antibody before or during their second RSV season as well.
Beyfortus has been shown to be quite safe. Limited side effects include a potential rash (0.9%) and/or pain, swelling, or hardness at the injection site (0.3%). Rarely, an allergic reaction can occur.
RSV preventive antibodies can be given at the same time as vaccines routinely recommended for infants and young children.