Introduction
The respiratory syncytial virus is a communicable virus causing respiratory infections. It commonly affects almost all children under two years of age. Sometimes it also affects adults. Most hospital admissions among young children are due to respiratory syncytial virus. This condition had no specific treatment initially, but the discovery of the drug Nirsevimab, which is under phase three trial, has provided better efficacy and safety in preventing the virus.
What Is a Respiratory Syncytial Virus?
A respiratory syncytial virus has led many children to be admitted to hospitals at a very young age due to the lack of specific treatment protocols developed at that time. It usually causes mild symptoms like a cold or can lead to serious complications that need immediate hospitalization.
What Are the Symptoms of a Respiratory Syncytial Virus Infection?
The symptoms start to appear within four to six after the virus enters the body. The most commonly reported symptoms are:
-
Runny nose.
-
Cough.
-
Sneeze.
-
Wheezing.
-
Decreased appetite in children.
The symptoms may vary among the children, and sometimes the only signs that occur are reduced activity and breathing difficulties. It usually resolves within one or two weeks. But, it can also cause serious medical conditions in the child, such as pneumonia (lung infection) and bronchiolitis (inflammation of the airways within the lungs). All children under two years of age develop this disease and are more prone to those with pre-existing lung diseases, immunocompromised conditions (weak immune system), and neuromuscular disorders (diseases affecting the nerves and muscles).
How to Prevent Children From the Risk of Developing the Respiratory Syncytial Virus?
The virus has a high chance of affecting premature infants and children under two years of age with a weakened immune system functioning. The following are the preventive measures to be followed for these children:
-
Regular washing of hands with soap and water to keep them germ-free.
-
Cover the mouth while coughing and sneezing with disposable tissues.
-
Avoid touching the eyes, nose, and mouth with unwashed hands.
-
The surfaces that the child touches more frequently are cleaned regularly.
-
When the child gets affected, they should stay at home and not mingle with other children to prevent the spread of infection.
What Is Nirsevimab?
Nirsevimab is a human recombinant monoclonal antibody that is effective against the respiratory syncytial virus. Recombinant monoclonal antibody refers to the antibodies produced through recombinant DNA (deoxyribonucleic acid) technology rather than testing the drug's efficacy by immunizing animals. Nirvesimab has been proven to reduce hospitalization in children due to respiratory infection by 75 percent. The drug is still not approved and is under phase three trials.
What Is the Mechanism of Action of Nirsevimab?
The virus usually attaches to the target protein within a cell and keeps multiplying to affect other cells leading to the spread of infection. The drug Nirsevimab binds to the fusion protein on the respiratory syncytial virus. In simple terms, it binds to the site where the virus tries to attach and competes with it, making it lose the ability to unite with the binding site. This process makes the virus useless and prevents its growth within the body.
What Is the Duration of Action of Nirsevimab?
The drug is given as a single dose to all children, irrespective of their weight. It is administered intramuscularly (within the muscles). Initially, a drug called Palivizumab was given as a treatment for this virus. But, the duration of action of Palivizumab was around twenty days which is less than Nirsevimab. The extended half-life of Nirsevimab is more advantageous to children. Half-life refers to the time the drug takes to reach half of its concentration. The average half-life of the drug is found to be around seventy to eighty days. The drug remains in the blood for at least 150 to 360 days and provides an effective immune response against the respiratory syncytial virus.
When Is Nirsevimab Administered?
Since the respiratory syncytial virus is responsible for ninety percent of hospitalization among children, the need for preventive strategies is increasing. Nirsevimab came to the rescue and provided effective treatment against the virus. The drug is administered to all the affected children. It is recommended to be administered as a prophylactic measure in recent times. Prophylaxis with Nirsevimab for the high-risk group is safe and effective in preventing the virus.
What Is the Dosage of Nirsevimab?
In the phase three trial for investigating the efficacy of Nirsevimab, a 50 milligrams dosage was administered to the children through an intramuscular route. This led to an increase in the formation of antibodies to the respiratory syncytial virus by four times the base values. The antibody increase was found to be consistent even after 150 days of administration of Nirsevimab.
What Are the Drawbacks of Nirsevimab?
One of the most significant drawbacks found during the phase three trial of the drug is the occurrence of anti-drug antibodies. Anti-drug antibodies refer to the formation of antibodies to the drug. This, in turn, decreases the concentration and efficacy of the drug. About 360 days after administering the drug, a few patients developed antibodies against the drug. But, this was found only in seven percent of the tested individuals. The rest of them had very effective progress towards the treatment and reduced the growing virus within the body.
What Is the Difference Between Nirsevimab and Palivizumab?
-
Palivizumab is a drug that was already proven and available to treat children with the respiratory syncytial virus. It is administered at a dose of 15 mg/kg weight of the child through an injection. It requires monthly visits to the doctor and getting the child injected with the drug. It was initially used in children ages less than six months, preterm infants of less than 35 weeks gestational age, and children with lung disease and congenital heart disease.
-
In contrast, Nirsevimab is a drug still under study. It is given at a dose of 50 milligrams to all children. It provides immunity against the virus, and monthly visits to the doctor to get the child injected are avoided. It is effective as a prophylactic drug and also in affected children.
Conclusion
Nirsevimab, a recombinant monoclonal antibody, is under phase three study trials and will reach markets soon. It helps provide an extended period of immunity against the respiratory syncytial virus, causing increasing hospitalization to almost all children by their second birthday. Incorporating this drug as a routine vaccination during early childhood is essential to protect the child against the respiratory syncytial virus.
