What is RSV?

RSV (Respiratory Syncytial Virus) is a virus that affects the lower respiratory tract and is a major cause of pneumonia and bronchiolitis in infants and young children. It is especially common during the rainy and winter seasons. In severe cases, it may require hospitalization, and some infants may need intensive care. RSV infection can also lead to long-term respiratory issues such as airway hyperreactivity, chronic cough, and asthma.

Children at higher risk of severe RSV lung infection include:

  - Premature infants with chronic lung disease

  - Children with congenital heart disease

  - Patients with cystic fibrosis

  - Children with severe immunodeficiency

Recently, there is a new preventive option in the medical field: Nirsevimab, a monoclonal antibody that provides effective protection against RSV. It can be administered to children from birth up to 2 years of age.

 

What Age Can Receive RSV Passive Immunization?

First Season

 - Healthy infants aged newborn to 12 months

 - Infants under 8 months are recommended to receive it, and it may be considered for those aged 8–12 months

 - High-risk infants who may develop severe complications, such as:

     - Premature infants with chronic lung disease

     - Children with severe immunodeficiency

     - Children with congenital heart disease still under treatment

Second Season

 - Infants aged newborn to 24 months who remain at high risk for RSV

 - Children aged 12-19 months with risk factors for severe disease

 - May be considered for children aged 19–24 months who are at high risk

 

Recommended Dosage

Infants weighing < 5 kg: 50 mg (single intramuscular injection)

Infants weighing > 5 kg: 100 mg (single intramuscular injection)

Children aged 12–24 months: 200 mg (intramuscular injection at two sites)

 

Effectiveness of RSV Passive Immunization (Nirsevimab) in Children

 - Reduces the risk of RSV infection by up to 79.5%

 - Lowers the risk of hospitalization due to RSV-related lower respiratory tract infections by up to 83.2%

 - Decreases the severity of illness requiring ICU admission and ventilator support by up to 75.3%

 - Provides protection for up to 5 months, effectively covering the RSV season

 

Is RSV Passive Immunization Safe?

RSV passive immunization (Nirsevimab) is derived from human antibodies and has a high safety profile. It has been developed and refined over time to provide longer-lasting protection. Previously, similar antibodies were used in high-risk children (such as those with heart disease) in a short-acting form requiring monthly injections (up to 5 doses per year).

This newer version offers longer duration with fewer doses and has already been used internationally for the past 3-4 years.

The risk of allergic reactions is very low, and side effects such as fever are rare and usually mild.

 

Benefits of RSV Passive Immunization (Nirsevimab)

1.Immediate Protection Against RSV
Nirsevimab provides ready-made antibodies that act immediately, offering protection from RSV during the highest-risk period-without waiting for the body to build immunity like a vaccine.

2.Reduces Disease Severity
Even if infection occurs after receiving Nirsevimab, symptoms are usually milder, lowering the risk of complications such as bronchiolitis or pneumonia and reducing the need for ICU care.

3.Reduces Hospitalization Rates
Studies show that Nirsevimab can reduce the risk of RSV-related hospitalization by 70-80%.

4.Long-Lasting Protection Throughout the Season
A single dose per RSV season provides protection for several months, effectively covering peak outbreak periods (typically during the rainy to winter seasons).

5.Safe for Both Healthy and High-Risk Children
Suitable for infants from birth to 12 months, including both healthy children and high-risk groups such as premature infants or those with heart or lung conditions.

6.Reduces Healthcare Costs and Care Burden
Helps lower hospitalization costs and reduces the burden of caring for severely ill children, giving families greater peace of mind and minimizing parental work absences.

7.Lowers Risk of Long-Term Respiratory Complications
May reduce the risk of long-term respiratory issues such as asthma or airway hyperreactivity.

8.Reduces Public Health Burden
RSV treatment in Thailand costs up to 1.75 billion THB per year, and prevention helps reduce this significant healthcare burden.

 

Important Notes

 - RSV passive immunization can be administered alongside routine vaccinations without any interval required

 - It can be given at the same time as other vaccines, at different injection sites

 

Conclusion

Preventing RSV is crucial for parents who want to protect their children from serious illness. If you have concerns, consult a pediatrician for appropriate guidance. Preventive care, such as RSV passive immunization with Nirsevimab, is an important strategy to protect infants during peak outbreak periods.

If you have a child in a high-risk age group, it is recommended to consult a doctor to evaluate suitability-because prevention is always better than treatment.

 

 

 

source : Vibhavadi Hospital