RSV Season Extended Through April: What the 2026 Guidance Means for Your Baby

Photo: Unsplash

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

Why RSV hits infants harder than adults

RSV causes cold-like symptoms in most older kids and adults, but in infants — whose airways are much smaller — the inflammation and mucus it produces can meaningfully narrow the airway, leading to bronchiolitis, an inflammation of the small airways in the lungs that makes breathing genuinely difficult. This is the core reason RSV immunization and monitoring focus so heavily on the youngest infants: the same virus that causes a mild cold in an older sibling can cause real respiratory distress in a baby under 6 months.

Who's considered higher risk

Beyond young age alone, babies born prematurely, those with chronic lung disease or certain heart conditions, and infants with weakened immune systems face a higher risk of severe RSV illness and are often prioritized for immunization even outside the standard age windows. If your baby was born early or has an underlying health condition, it's worth confirming with your pediatrician whether extended or additional RSV protection applies to your specific situation.

Telling RSV apart from a common cold

Early RSV symptoms — runny nose, mild cough, low fever — often look identical to an ordinary cold, which is part of why it can be hard to know when to worry. The signs that suggest RSV is progressing toward something more serious are the ones in the checklist below: rapid or labored breathing, wheezing, and reduced feeding, rather than the initial cold-like symptoms alone. Most RSV cases in older, healthy children still resolve like a typical cold without needing emergency care.

Home care for milder cases

For RSV that isn't causing breathing distress, supportive care is the mainstay: saline drops and gentle suctioning to clear a stuffy nose (especially important for young infants who breathe primarily through the nose), a cool-mist humidifier, staying on top of fluids, and fever management as directed by your pediatrician. There's no antiviral medication routinely used for typical RSV infections in otherwise healthy infants — treatment is about managing symptoms while the illness runs its course.

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

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.

How RSV spreads, and why daycare and preschool matter

RSV spreads mainly through respiratory droplets from coughing and sneezing, and through contact with a contaminated surface followed by touching the eyes, nose, or mouth. The virus can survive on hard surfaces like crib rails, toys, and countertops for several hours, which is part of why daycare and preschool settings, where young children share close space and put shared toys in their mouths, see so much RSV transmission during the season. Frequent handwashing, routine cleaning of shared surfaces and toys, and keeping a child with cold symptoms home when possible all reduce the chance of passing RSV along to other children, especially younger infants in the same household or classroom.

General prevention steps every family can use

The CDC's RSV guidance page covers prevention basics in more detail, but the core habits are the same ones that help with most respiratory illnesses.

How RSV testing and diagnosis usually work

Most mild cases of RSV are diagnosed based on symptoms alone, without a specific test, especially when a child is otherwise doing well and just has cold-like symptoms. When a pediatrician does want to confirm RSV, typically because a baby is being evaluated for more significant breathing difficulty or is being considered for hospital admission, a simple nasal swab test can usually give a result within an hour. A positive RSV test on its own does not automatically mean hospitalization is needed. It mainly helps guide monitoring and, in a hospital setting, helps separate RSV patients from patients with other contagious illnesses.

What a typical RSV illness timeline looks like

For most infants and toddlers, RSV follows a fairly predictable arc: two to three days of mild cold symptoms, followed by a period, often days three through five, when cough and congestion peak and breathing difficulty, if it is going to happen, tends to show up. After that, most children gradually improve over one to two weeks, though a lingering cough can stick around longer. Knowing that days three through five tend to be the roughest stretch helps some parents feel less alarmed by a worsening cough at that point, while still watching closely for the specific warning signs of severe illness described above.

RSV compared with a cold, the flu, and COVID-19

Because RSV, common colds, influenza, and COVID-19 can all start with similar symptoms in a young child, it can be genuinely hard to tell them apart without testing. Colds tend to stay mild and resolve within a week or so without significant breathing trouble. Influenza more often brings a higher, more sudden fever and body aches in older children. COVID-19 symptoms vary widely by variant and can include loss of taste or smell in older kids, though this is less noticeable in infants. RSV stands out mainly for how it can affect the smallest airways in babies specifically, making wheezing and labored breathing more of a concern in infants than in older children or adults with any of these illnesses. When in doubt, your pediatrician's office can help sort out which is most likely and whether testing is worthwhile.

A note for parents of premature infants

Babies born prematurely have smaller airways and less mature immune systems, both of which raise the stakes with RSV specifically. Many pediatric and neonatal specialists recommend extra precautions for preemies during RSV season: limiting visitors in the early months, avoiding group childcare settings if possible during peak season, and confirming immunization eligibility as early as it can be given. If your baby spent time in a NICU, it is worth asking your pediatrician directly whether your family should be taking any additional RSV precautions this season, since guidance can be more individualized for preterm infants than the general recommendations above.

When it is reasonable to go straight to the ER versus calling first

A daytime call to your pediatrician's office is usually the right first step for gradually worsening cold symptoms, mild wheezing, or general concern without acute distress. Going straight to the emergency room, rather than waiting for a callback, makes more sense for sudden or severe breathing difficulty, a bluish color around the lips or face, a baby who is limp or very hard to wake, or signs of significant dehydration such as no wet diapers for eight or more hours. If you are ever unsure which situation you are in, err toward calling and describing exactly what you are seeing rather than trying to decide the severity yourself. Pediatric triage lines and many pediatricians' after-hours services exist specifically to help sort out urgency over the phone, and using them is never an overreaction.

Myths worth clearing up

A few misunderstandings come up often. RSV immunization with nirsevimab or clesrovimab is not a vaccine that trains a baby's own immune system, so it does not carry the same mechanism, or the same schedule, as routine childhood vaccines, and that is by design rather than a shortcoming. A baby who already had RSV once can still get it again, since immunity from a prior infection is partial and temporary rather than lasting. And a "mild" RSV season regionally does not mean an individual baby's risk is low, since severity depends heavily on age, prematurity, and underlying health, not just how much virus is circulating in a given area.

Frequently asked questions

Keep reading

Common Childhood Illnesses

Measles: What Parents Should Know

Fever in Babies: What to Do