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Respiratory syncytial virus (RSV) season got off to a late start this year, but activity has stayed elevated longer than usual — enough that most states have extended eligibility for RSV immunizations through the end of April. Here's what's actually changed, and what it means if you have a baby at home.
What's happening this season
Since the season began last fall, there have been more than 46,000 pediatric hospital admissions for RSV in the U.S., the large majority in children under 5. Because the season started later than typical and cases have remained high, most state health departments have extended the window for eligible infants and toddlers to receive RSV immunization through April, rather than cutting it off earlier in the year as in past seasons.
The current AAP recommendations
- Infants under 8 months entering their first RSV season should receive nirsevimab or clesrovimab, unless the pregnant parent received the maternal RSV vaccine at least 14 days before delivery.
- Infants and children 8 through 19 months at high risk of severe RSV disease entering their second RSV season should receive nirsevimab (clesrovimab is not indicated for this age group).
- Abrysvo® is the only RSV vaccine currently recommended during pregnancy, typically given in a specific window in the third trimester.
- If the vaccinated parent received Abrysvo at least 14 days before birth, the baby generally does not need an additional immunization at birth.
Nirsevimab vs. clesrovimab: what's the difference?
Both are monoclonal antibody products that give babies short-term protection against severe RSV disease — they aren't vaccines in the traditional sense, since they don't train the immune system to produce its own antibodies, but rather provide the antibodies directly. Nirsevimab is approved for a broader age range, while clesrovimab is authorized specifically for infants under 8 months entering their first season.
What to do if you're not sure your baby is covered
If you're unsure whether your baby already received an RSV immunization, or whether you got Abrysvo during pregnancy, your pediatrician's office can check your child's immunization record and let you know whether anything is recommended before the season winds down. Given the extended window this year, it's worth asking at your next visit rather than assuming the season has already ended.
Signs of severe RSV to watch for
- Rapid or labored breathing, or visible chest retractions
- Wheezing or a persistent, worsening cough
- Bluish color around the lips or fingertips
- Poor feeding or signs of dehydration
- Unusual lethargy or difficulty waking
Any of these warrant an urgent call to your pediatrician or a trip to urgent care or the ER, especially in infants under 6 months.
