When the fall season approaches, it becomes crucial to shift our focus toward something that makes its regular appearance: the respiratory syncytial virus (RSV) season. This time of year, the health care community is on increased alert especially when it comes to safeguarding the well-being of our tiniest patients, those 24 months and under, who require additional protection during the RSV season.

RSV is a common respiratory virus that can lead to mild cold-like symptoms in older children and adults. However, it can be more severe in infants and young children, particularly those under 12 months of age who are at an increased risk of hospitalizations and severe illnesses, including babies with weakened immune systems or underlying health conditions. According to the Centers for Disease Control and Prevention (CDC), RSV is responsible for approximately 58,000 to 80,000 hospitalizations in children under the age of 5, posing a significant concern for pediatric health care providers and parents alike.

There is now a transformative breakthrough in protecting the most vulnerable population against RSV infection – a vaccine. The Food and Drug Administration (FDA) recently granted approval for the use of Nirsevimab, a new monoclonal antibody medication intended to offer passive immunity against RSV in infants and children up to 24 months of age. The medicine is administered via a single intramuscular injection.

To help you gain a better understanding of RSV and how Nirsevimab offers a promising solution to mitigate the impact of severe RSV infections in the youngest patients, check out these frequently asked questions.

What Parents Need to Know: 10 Frequently Asked Questions about RSV and Nirsevimab

1. When do we see an increase in RSV infection cases among children?

We see an uptick in respiratory syncytial virus (RSV) cases from October to March, especially among children under the age of 1 year. However, the COVID-19 pandemic drastically changed the dynamics of RSV transmission. During the first winter of the pandemic, RSV cases virtually disappeared due to the widespread adoption of hygiene practices, social distancing and isolation measures. Subsequently, we saw an unexpected surge in RSV cases in the summers of 2021 and 2022 as COVID-related precautions relaxed and interactions increased. This influx in RSV cases overwhelmed our health care facilities, pediatric units and emergency rooms. Fast forward to the summer of 2023 – RSV cases have remained noticeably low – which suggests a possible return to a more standard RSV season aligning with the typical October to March time frame.

2. Who is at risk for RSV?

RSV poses the highest risk to infants and children under the age of 1 year. Pre-term infants with underlying lung disease or congenital heart conditions are especially vulnerable. While older children and adults can contract RSV, the severity of the illness is generally less in these groups.

3. How does Nirsevimab protect my child from RSV?

Nirsevimab acts as a supplement to the immune system. Unlike a traditional RSV vaccine, which uses a small fragment of the RSV virus to stimulate the body’s immune response and recognition of RSV (thus providing protection upon exposure to the actual RSV virus), Nirsevimab is made from synthetic proteins called monoclonal antibodies. These extra antibodies bind to the RSV virus, preventing it from attaching to and infecting cells in the respiratory tract, and neutralizes the virus before it can cause infection or illness. Nirsevimab offers babies a temporary shield against RSV until their immune systems are mature and better equipped to fight off infections. It is recommended for use in the highest risk populations, infants under 12 months of age.

4. When should Nirsevimab be administered to my child?

The CDC recommends babies under the age of 8 months should receive the RSV medication before the start of the RSV season, which usually spans from October to March. Newborns born during the RSV season should ideally receive the medication within their first week of life. For infants already in the 8-to-9 month range, and for those babies with certain high-risk conditions, a second dose of the RSV medication may be administered in the following RSV season. Most children will get the shot once in their life, but for a small population of high-risk patients, they will receive a second dose the next year.

5. Why isn’t this RSV medication given to children older than 2 years of age?

When it comes to older children, they are indeed susceptible to RSV, but the primary risk of severe illness and hospitalization lies in those under 1 year of age. While 3- and 4-year-olds can contract RSV, their symptoms are often akin to the common cold, consisting of a runny nose, cough and congestion. Considering this, Nirsevimab is not recommended for these older children; rather, its primary focus remains on the demographic most vulnerable to severe illness and hospitalization.

If you have a household with multiple children, particularly if one is age 8 months or under and there’s an older sibling attending daycare or pre-K, the potential for RSV transmission from school to home is substantial. In these scenarios, parents should consider choosing this injection for their infant as a preventive measure.

6. Can my child get the RSV medication along with other seasonal shots?

Certainly. The RSV medication can be administered alongside other routine childhood vaccinations. Your child’s pediatrician will likely coordinate this during the upcoming fall and winter season. Combining vaccines is a common practice and can help protect children against multiple illnesses in one visit.

7. How long does Nirsevimab offer protection?

Nirsevimab can provide protection against RSV for at least four to five months with just a single dose. This can be especially beneficial for infants who have not yet developed a strong immune response of their own. While the exact duration of protection beyond this time frame is not yet fully determined, this new monoclonal antibody offers valuable coverage during the critical RSV fall and winter months.

8. How safe and effective is Nirsevimab?

Nirsevimab has demonstrated remarkable effectiveness. In clinical trials, it was found to be about 70% to 80% effective at preventing against RSV infection and reducing the severity of this illness. This level of effectiveness can have a substantial positive impact for a disease burden as significant as RSV.

Safety data from clinical trials and previous experience with a similar medication, palivizumab, suggest a very favorable safety profile with minimal adverse effects for both preterm babies and full-term babies.

9. What are the side effects?

The most common side effect is minor discomfort at the injection site. Similar to other injections, there might be some pain, tenderness or swelling.

10. Are there any children who should not receive the RSV medication?

As of now, there are no contraindications or conditions that prevent children from receiving the RSV medication. If your baby is at high risk for severe illness due to factors like compromised heart or lung health, or if your baby is younger than 8 months old with these conditions, it’s actually recommended to go ahead and get the shot. So, having underlying conditions doesn’t exclude your baby from receiving the RSV medication; in fact, it can be even more important for your baby to receive it.

Nirsevimab and proper hygiene: Double defense against RSV

Alongside Nirsevimab, hygiene measures and other infection prevention practices, which played a pivotal role in the decline of RSV for two years, stand as a vital defense against infections. Encouraging children at a young age to learn proper handwashing techniques can contribute significantly to their protection.

The overall impact of RSV is significant. Imagine the relief if a substantial number of parents choose to provide the new RSV medication to their babies. By potentially reducing the number of visits to the ER, intensive care and doctor’s offices, the collective impact on health care, families and children could be monumental. Coupled with proper hygiene practices, Nirsevimab has the potential to make a positive impact on the health and well-being of babies and their families heading into the annual RSV season.

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