Respiratory Syncytial Virus Vaccines

Introduction

The respiratory syncytial virus (RSV) is one of the global causes of lower respiratory tract infections (LRTI) in newborns and children. RSV also significantly increases the risk of LRI in the elderly and immunocompromised patients. The respiratory syncytial virus is one of the most frequent causes of respiratory infections in children.

What Is Respiratory Syncytial Virus?

Respiratory syncytial virus is a common respiratory virus that is known to cause flu-like symptoms. People affected by the virus usually recover in a week or two, though some have had some complications. Hospitalization might be essential When the condition worsens, especially in infants and older people. In some cases, it can affect the lungs, making it difficult to breathe in small children. During the colder seasons, infection rates tend to increase, resulting in bronchiolitis(an infection of the respiratory tract) in newborns, common colds in adults, and more serious respiratory illnesses like pneumonia (an inflammation of the air sacs in the lungs) in the elderly and immunocompromised.

What Are the Symptoms of Respiratory Syncytial Virus?

When infected with the virus, people usually show symptoms four to six days after infection. The common symptoms of RSV include:

• Decreased appetite.

• Dry cough.

• Running nose.

• Sneezing.

• Fever.

• Chest congestion.

• Sore throat.

• Headache.

RSV infection can spread to the lower respiratory tract, resulting in pneumonia or bronchiolitis (inflammation of the small airway passages leading to the lungs). The signs of the condition becoming worse may include:

• Severe cough.

• Fever.

• Difficulty in breathing.

• Wheezing.

• Cyanosis (bluish skin discoloration due to the lack of oxygen supply).

• Shorts and rapid breathing that is shallow are seen in infants.

• Tiredness.

How Is RSV Spread?

Nearly all children get exposed to the virus before turning two years old. Most people contract RSV for the first time when they are infants or toddlers. However, recurrent infections can happen at any stage of life and affect individuals of any age. Individuals who have contracted RSV are typically infectious for three to eight days, though they may start to show symptoms a day or two earlier. But for as long as four weeks after they stop exhibiting symptoms, some newborns and those with compromised immune systems can carry on spreading the virus. At daycare facilities or schools, for example, children are frequently exposed to and contract RSV infection. After that, they could infect other family members with the virus. RSV can survive on hard surfaces like cradle rails and tables for several hours. However, it usually spends less time on soft surfaces like hands and tissues. The common methods of how the virus spreads can include:

• Cough or sneeze of an infected person.

• Droplet infection spreads from an infected person.

• Kissing or direct contact with an infected person.

• Hard surfaces, like the knobs of doors, and cradle handles, can have the virus for longer periods. Touching the face after touching an infected surface can spread the infection.

How Is the Spreading of the Infection Prevented?

RSV vaccinations offer protection against severe illness from RSV for individuals aged 60 and older. Due to the decreased immunity associated with aging, older adults are more vulnerable to serious complications from RSV than younger adults. Furthermore, several underlying medical conditions may raise the likelihood of developing severe RSV illness. Due to the weakened immune systems associated with aging, older adults are more vulnerable to serious complications from RSV than young adults. In addition, the probability of contracting a severe illness from RSV may be elevated by specific underlying medical conditions. RSV vaccination may be especially beneficial for older people with these conditions.

What Are the Immunizations Available for RSV?

• Early Attempts: The development of the RSV vaccine commenced in the 1960s with the introduction of an ineffective vaccine called formalin-inactivated RSV (FI-RSV). It caused a severe and fatal lung inflammatory response in infants who were previously RSV naive. Immunization-associated increased respiratory illness (ERD) is the term used to describe this reaction to spontaneous RSV infection. For many years, the development of substitute RSV vaccinations was hampered by concerns around the FI-RSV vaccine.

• First Successful Vaccine: The first successful RSV vaccine, Abrysvo, was licensed by the Food and Drug Administration (FDA) in 2023 for use in pregnant women to prevent severe RSV disease in the first six months following delivery. According to the FDA guidelines, the vaccination can be given between 32 and 36 weeks of gestation.

• Further Developments: A long-acting monoclonal antibody medication called Nirsevimab was advised by the Centers for Disease Control and Prevention (CDC) in 2023 to prevent RSV in newborns and young children. All newborns under eight months old who are born during or about to enter their first RSV season should receive one dose of Nirsevimab, according to the CDC. An administration of the drug during the second season of life is advised for certain children between eight and 19 months. It is generally recommended for those who are more susceptible to severe RSV disease, like those with impaired immune systems. It has been demonstrated that the drug helped to reduce the likelihood of hospitalizations and other emergencies in newborns by around 80 %. The American Academy of Pediatrics (AAP) has approved Palivizumab, a different monoclonal antibody medication, for some infants under 24 months old who are more likely to require hospitalization due to RSV infection.

• RSV Vaccine for Pregnant Women: To avoid RSV-related lower respiratory tract infections in babies, the American College of Obstetricians and Gynecologists advises pregnant women between 32 and 36 weeks of gestation to get a single dose of RSV vaccine (Abrysvo), administered seasonally. RSV season runs from September to January in the majority of the United States. Therefore, RSV vaccine is advised for pregnant women between September and January, much like the seasonal influenza vaccination. The majority of neonates and infants will not need the administration of monoclonal antibodies in addition to maternal immunization. However, infants born at less than 34 weeks should receive Nirsevimab regardless of the mother's vaccination status. The earliest time for the vaccination is during 32 weeks of pregnancy. It would take at least 14 days after the mother's vaccination for the development and transplacental transfer of maternal antibodies to protect the baby. It is advised that all babies who were born during or shortly after their first RSV season should be given one dose of Nirsevimab. For babies and kids eight to 19 months old who are starting their second RSV season and are more likely to develop severe RSV disease, one more dose of Nirsevimab is recommended.

Conclusion

RSV is a very contagious virus that affects people of all ages, infecting the lungs and respiratory tract. Its transmission is seasonal; it usually peaks in the winter following its onset in the fall. The use of vaccines helps to protect the older people. On the other hand, products containing monoclonal antibodies are available to shield young children and newborns from severe RSV.