“This new RSV immunization provides parents with a powerful tool to protect their children against the threat of RSV,” said CDC director Mandy Cohen, who recently adopted the CDC advisory committee’s recommendation for the use of nirsevimab. “RSV is the leading cause of hospitalizations for infants and older babies at higher risk and today we have taken an important step to make this life saving product available.”
RSV, or respiratory syncytial virus, is one of the most common causes of childhood respiratory illness, prompting annual outbreaks of respiratory illnesses in all age groups. An estimated 58,000 to 80,000 children under five years of age, most of them infants, are hospitalized each year nationwide due to an RSV infection, the CDC says. Each year, an estimated 100 to 300 children younger than five years old die due to RSV.
Nirsevimab was approved last month by the U.S. Food and Drug Administration. It is administered as an injection, providing infants and toddlers with antibodies to protect against severe RSV illness during their first RSV season when they’re most at risk.
This new shot also isn’t a vaccine, doctors say. A vaccine stimulates the body’s immune system to develop antibodies against a specific infection, but monoclonal antibodies, like in nirsevimab, provide passive immunity.
“Passive immunity is when antibodies to an infection are given to a person to help prevent or treat a disease,” said Dr. Michael Klatte, chief of infectious disease at Dayton Children’s.
This passive immunity lasts for however long the antibodies remain in the body, which is about five months for a dose nirsevimab, Klatte said.
Dayton Children’s experienced an early surge in RSV infections last year, filling beds in its hospital in October with RSV patients instead of in January or February, like in pre-pandemic years. Klatte is anticipating a similar trend this year but is hopeful for future years that this new immunization will help alleviate severe illness.
“I fully anticipate that during this coming fall and winter we’ll still see a good number of infants hospitalized with RSV,” Klatte said. “However, with widespread uptake of this shot, I’m optimistic that within the next two to threes years we’ll begin referring to RSV in terms of how we talk about measles, rotavirus, and whooping cough; namely, as a relatively rare cause of infection.”
This shot has the potential to dramatically decrease the number of infants who develop severe RSV infection, Klatte said. Nearly all kids have been infected with RSV at least once before the age of two years, he said. Between 1-3% of all children under one year old who catch RSV are hospitalized with a severe infection, but nirsevimab decreases the risk of hospitalization by about 80%.
“To put this in some perspective, there are roughly 6,200 infants born in Montgomery County per year,” Klatte said. “If all these infants develop RSV infection, then about 100-200 of them will need to be hospitalized at Dayton Children’s Hospital. However, if all those infants get nirsevimab, then only 20-40 infants would end up getting admitted to the hospital.”
The CDC is recommending infants younger than eight months, born during – or entering – their first RSV season (typically fall through spring) receive one dose of nirsevimab. For a small group of children between the ages of eight and 19 months who are at increased risk of severe RSV disease, such as children who are severely immunocompromised, a dose is recommended in their second season.
Nirsevimab is expected to be available this fall. Dayton Children’s Hospital anticipates having nirsevimab available for use prior to the start of this year’s RSV season. Since the CDC recommends infants under eight months and newborns receive this shot prior to their first RSV season, Klatte said it will also be important for birthing hospital partners in the region and for pediatricians’ offices in the community to have nirsevimab available for patients.
The CDC’s advisory committee also voted to include nirsevimab in the Vaccines for Children program, which provides recommended vaccines and immunizations at no cost to about half of the nation’s children. Additional clinical guidance and health care provider education material will be provided by CDC in the coming months.
“As we head into respiratory virus season this fall, it’s important to use these new tools available to help prevent severe RSV illness,” said Cohen. “I encourage parents of infants to talk to their pediatricians about this new immunization and the importance of preventing severe RSV.”
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