FDA Approved RSV Vaccines

What Is Respiratory Syncytial Virus (RSV)?

RSV, or respiratory syncytial virus, is a respiratory infection known to cause cold-like symptoms in adults but is particularly serious in young infants and older people. RSV causes infection in the lower respiratory tract and can further lead to a very severe condition.

The high-risk individuals likely to get affected by this severe disease include premature infants and newborns under six months of age who require intensive care during the first few weeks or months after birth and children suffering from any underlying lung or heart disease. RSV can cause respiratory problems, such as breathing difficulties in young infants, leading to hospitalization and death.

Common Symptoms of RSV:

• Coughing.

• Running nose.

• Sneezing.

• Decreased appetite.

• Wheezing.

• Fever.

• Troubled breathing.

• Straining of chest and flaring of nostrils while breathing.

Who Are at a High Risk of Getting Infected With RSV?

Infants, children, and adults with underlying medical conditions are usually at a higher risk of contracting RSV-caused diseases. These include:

• Infants of six months or younger.

• Premature infants.

• Immunocompromised children.

• Younger children (under 2 years) with congenital heart disease and chronic lung disease.

• Children have severe cystic fibrosis, congenital anomalies, and neuromuscular disorders.

• Adults suffering from lung diseases, such as asthma and chronic obstructive pulmonary disorder (COPD), and cardiovascular disorders, such as coronary artery disease and congestive heart failure (CHF).

• Adults suffering from diabetes mellitus, neurological conditions, liver and kidney disorders, hematological disorders, and compromised immune systems.

What Is Respiratory Syncytial Virus (RSV) Vaccine?

The United States Food and Drug Administration (FDA) has approved Pfizer’s vaccine for preventing lower respiratory tract diseases caused by respiratory syncytial virus (RSV) in adults over 60 years and older and infants and newborns less than six months. In infants, the goal can be achieved through an active immunization of the mother or pregnant women in the 32 to 36 weeks of the gestational period. The vaccine aims to protect the newborn from this highly contagious disease, whereas, earlier, this vaccine was only approved for use in adults of about 60 years and above. The vaccine works by developing immunity against two types of RSV proteins or antigens - RSBpreF A and RSVpreF B- so that if a person (infant or adult) gets infected, their immune system can recognize and destroy the virus.

The RSV vaccine for adults got FDA approval on May 31, 2023, and the other one, which can be given to pregnant women to protect infants during pregnancy, got approval on August 21, 2023.

What Are the Ingredients Present in RSV Vaccine?

• RSV vaccines are a subunit of bivalent recombinant stabilized perfusion F protein (RSVpreF). It consists of equal amounts of preF or stabilized antigens from two RSV groups, RSV A and RSV B.

• The vaccine is supplied in a kit containing a white sterile powder or Lyophilized Antigen Component, a prefilled syringe that contains a sterile water diluent component, and a vial adapter.

• Each dose of RSV vaccine is approximately 0.5 mL (milliliters) after reconstitution and contains 60 mcg (micrograms) of RSV preF A and 60 mcg RSV preF B (total of 120 mcg of RSVpreF) per 0.5 mL.

• The buffer ingredients present in the vaccine are as follows: 1.04 mg (milligrams) tromethamine hydrochloride, 0.11 mg tromethamine, 11.3 mg sucrose, 0.08 mg polysorbate 80, 22.5 mg mannitol, and 1.1 mg sodium chloride per 0.5 mL.

• Additionally, the vaccine may contain DNA (deoxyribonucleic acid) and residual amounts of host cell protein for manufacturing purposes. There are no preservatives used in this vaccine.

What Is the Efficacy of RSV Vaccine?

The drug has shown 67 percent efficacy in adults in reducing the risk of lower respiratory tract diseases (LRTD) caused by RSV with two or more symptoms and about 86 percent efficacy in those with three or more symptoms. Also, when the drug was given to a pregnant person to protect infants during pregnancy against RSV, the risk of LRTD was reduced to 81.8 percent within 90 days and 69. 4 percent within 180 days after the infant’s birth.

What Are the Common Side Effects of RSV Vaccine?

• The side effects experienced by the pregnant people were nausea, headache, pain at the injection site, and muscle pain.

• The most common side effects in adults 60 years and above were headache, fatigue, muscle pain, and pain at the injection site.

The comparison of the RSV vaccine with Placebo in clinical trials revealed that infants experienced low birth rates and jaundice, which was 5.1 percent RSV vaccine versus 4.4 percent Placebo and 7.2 percent RSV vaccine versus 6.7 percent placebo, respectively.

What Are the Important Safety Measures for RSV Vaccines?

1. Anaphylactic Reactions: The drug is not recommended for an individual having a history of allergic reactions, such as anaphylaxis, to this drug or any of its components.

2. Syncope: A person can experience fainting (syncope) after taking the RSV vaccine, like any other injectable medication. Therefore, precautions must be taken to avoid injury during fainting or fall.

3. Pregnancy: It is recommended that the vaccine should be given to pregnant people only during 32 to 36 weeks of the gestational phase to avoid any risk of preterm birth.

4. Immunosuppression: Few adults with compromised immunity receiving medication to suppress the immune system may show reduced response to this vaccine.

5. Limitations: The drug cannot protect all people.

6. Side Effects: The side effects of the vaccine occur in adults 60 years and above, which include headache, fatigue, muscle pain, and pain at the site of injection. The side effects also occur in pregnant people, which include nausea, headache, pain at the injection site, and muscle pain.

How Should This Vaccine Be Stored?

The drug should be stored in the refrigerator before reconstitution, at 2°C to 8°C (36°F to 46°F), and in its original carton. It should not be frozen; if the carton gets frozen during storage, it should be discarded.

After reconstitution, the vaccines should be administered immediately or can be stored for up to four hours at room temperature. If not used within four hours, the reconstituted vaccine must be discarded safely.

Conclusion

RSV can lead to a life-threatening condition; therefore, this FDA-approved vaccine for RSV has proved to be a blessing. Additionally, the RSV vaccine's potential benefits have outweighed the effects caused by the respiratory syncytial virus. Therefore, the drug is considered safe to protect infants, children, and adults from LRTD caused by RSV.