What is RSV?

Respiratory syncytial virus (RSV) ) is a type of enveloped virus that causes respiratory tract infections. After you get RSV, you are immune to it. But this immunity is not lifelong, leaving the possibility of reinfection with RSV.

 

When infected with RSV, what are the symptoms?

People infected with RSV usually show symptoms within 2 - 8 days after getting infected, which can resemble those of a common cold, such as fever, cough, sneezing, and a stuffy or runny nose. However, if the virus spreads to the lower respiratory tract, it may lead to various complications, such as bronchiolitis or pneumonia. In severe cases, the symptoms can include rapid breathing, wheezing, and a blue color to the skin. These symptoms can be life-threatening, necessitating urgent hospital treatment.

 

How can RSV be transmitted?

RSV can be transmitted through various bodily secretions such as nasal discharge, saliva, and droplets from coughing or sneezing of infected individuals. It can also be transmitted through direct contact with contaminated surfaces such as toys, doorknobs, tables, chairs, etc. The virus can survive on surfaces for several hours.

 

Who is at high risk for severe RSV infection?

• Infants born prematurely (at or before 35 weeks)
• Infants up to 1 year old
• Children younger than 2 years with chronic lung disease or congenital heart disease
• Older adults
• Adults with chronic lung or heart disease
• Adults with diabetes
• Adults with weakened immune systems, such as HIV patients or patients receiving chemotherapy

 

How to prevent RSV infection?

Currently, there is no specific treatment for RSV infection, only supportive care based on symptoms is available. Therefore, prevention of RSV infection is crucial. This can be achieved by maintaining good health, avoiding close contact with infected patients, always washing hands before and after touching various things, and ensuring cleanliness of everyday items such as toys, clothing, and bedding. Additionally, there are medication and vaccine available for preventing RSV infection in individuals who are at high risk during seasonal outbreaks of RSV.


1. Monoclonal antibody injection for children at high risk

1.1 "Palivizumab" is a monoclonal antibody for preventing RSV infection in children at high risk of RSV infection, including:

• Infants who are born prematurely (born at 35 weeks or less), and who are 6 months of age or younger at the beginning of RSV season
• Infants who have a chronic lung condition known as BPD/CLDP (bronchopulmonary dysplasia/chronic lung disease of prematurity) that required medical treatment within the previous 6 months, and who are 24 months of age or younger at the beginning of RSV season
• Infants who have a heart condition known as HS-CHD (hemodynamically significant congenital heart disease), and who are 24 months of age or younger at the beginning of RSV season

This medication can reduce RSV hospitalizations, shorten hospital stays for RSV treatment, decrease the likelihood of admission to the pediatric intensive care unit, and lessen the severity of lower respiratory tract infections in children at risk of RSV infection during outbreak seasons.
 

How should Palivizumab be injected?

The recommended dose of Palivizumab is 15 mg/kg of body weight, administered monthly via intramuscular injection. The first dose should be given before the start of the RSV season, with subsequent doses administered monthly, totaling 5 months (5 injections) during the RSV outbreak season.
 

How effective is Palivizumab?

Studies have demonstrated palivizumab's efficacy. It can reduce hospitalizations due to RSV by 78% in preterm infants (born before 35 weeks of pregnancy) and by 39% in children with BPD. Palivizumab is also effective in reducing hospital admissions for RSV infection by 45% in children with HS-CHD.
 

Possible Side Effects of Nirsevimab

The most common side effects of Palivizumab are fever, rash, and injection-site reaction.

1.2 Nirsevimab is a monoclonal antibody approved for preventing RSV infection during outbreak seasons in children, specifically:

• Newborns and infants during their first RSV season.
• Children under 2 years old who remain at risk during their second RSV season.

 

How is Nirsevimab administered?

Nirsevimab is a monoclonal antibody used to protect infants against respiratory syncytial virus (RSV). It is typically administered as a single intramuscular injection, and the dosage depends on the infant’s weight.

• For infants:
  • Weighing less than 5 kg: 50 mg
  • Weighing 5 kg or more: 100 mg
• For high-risk children: 200 mg

The injection should be administered before the RSV season begins. If an infant is born during the RSV season, the dose should be given immediately after birth. Nirsevimab can also be administered alongside other routine vaccines.

How effective is Nirsevimab?

Nirsevimab provides protection for up to 5 months, covering the typical RSV season. Studies show that it:

• Reduces RSV infection risk by 79.5%.
• Lowers the need for hospitalization due to RSV in the first year of life.
• Decreases RSV-related lung infections requiring hospitalization by 83.2%.
• Reduces ICU admissions due to RSV by 75.3%.
• Shortens hospital stay duration and lessens disease severity.

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Possible Side Effects of Nirsevimab

Common side effects include: fever, skin rash, pain, swelling, or redness at the injection site


2. RSV vaccine
Currently, there are 2 types of RSV vaccine available in Thailand:

2.1 RSV recombinant adjuvanted vaccine
This vaccine is used to prevent lower respiratory tract disease (LRTD) caused by RSV in adults 60 years of age and older, and adults 50 through 59 years of age who are at increased risk for RSV disease.
 

How should the vaccine be injected?

This vaccine is administered as a single-dose shot via intramuscular injection.

 

How effective is the RSV recombinant adjuvanted vaccine?

The RSV recombinant adjuvanted vaccine is effective in preventing LRTD caused by RSV in adults 60 years of age and older, with efficacy up to 82.6%. Additionally, in adults 60 years of age and older with at least 1 of the following comorbidities: chronic obstructive pulmonary disease (COPD), asthma, chronic respiratory/lung disease, chronic heart failure, diabetes, and chronic liver or kidney disease, the vaccine has been found to be up to 94.6% effective in preventing LRTD caused by RSV.

 

What are the possible side effects after getting this vaccine?

The most common side effects are injection-site pain, fatigue, muscle pain, headache, and joint pain. These side effects are usually mild and resolved within a few days after vaccination.


2.2    RSV bivalent recombinant vaccine
This vaccine is used to prevent LRTD caused by RSV in adults 18 years of age and older. It is also given to pregnant women from 24 through 36 weeks of pregnancy to prevent LRTD caused by RSV in infants from birth through 6 months of age.

How should the vaccine be injected?

This vaccine is administered as a single-dose shot via intramuscular injection.
 

How effective is the RSV bivalent recombinant vaccine?

Adults 18 years of age and older

The RSV bivalent recombinant vaccine is highly effective in protecting adults aged 18 and over from LRTD caused by RSV. It can reduce the risk of LRTD caused by RSV with 3 or more respiratory symptoms by 86%, and reduce the risk of LRTD caused by RSV with 2 or more respiratory symptoms by 67%.
(The respiratory symptoms include cough, wheezing, sputum production, shortness of breath, and tachypnea.)

Infants from birth through 6 months of age
The RSV bivalent recombinant vaccine, administered during pregnancy, is highly effective in reducing the risk of severe LRTD caused by RSV in infants. It is up to 82% effective at 3 months of age and 69% effective at 6 months of age. Moreover, the vaccine is also effective in reducing hospitalizations of infants from LRTD caused by RSV. It can reduce hospitalizations by 68% in infants at 3 months of age and 57% in infants at 6 months of age.

 

What are the possible side effects after getting this vaccine?

Adults 18 years of age and older
The most common side effects are injection-site pain, fatigue, muscle pain, and headache. These side effects are usually mild to moderate and resolved within 1-2 days.

Pregnant women
The most common side effects are injection-site pain, headache, muscle pain, and nausea. These side effects are usually mild to moderate and resolved within 2-3 days.
 
If you need further information, you can contact the Drug Information Center at Bumrungrad International Hospital 24 hours a day.