From the FDA Drug Label
Each injection of SYNAGIS helps protect your child from severe RSV disease for about 1 month. The duration of immunity provided by the Respiratory Syncytial Virus (RSV) vaccine, Synagis, is about 1 month per injection, with injections needed every 28-30 days during the RSV season 1.
From the Research
The RSV vaccine protection typically lasts for one respiratory virus season, which is approximately 5-6 months, as demonstrated by the most recent and highest quality study 2.
Duration of Immunity
The duration of immunity provided by the Respiratory Syncytial Virus (RSV) vaccine varies depending on the population and the specific vaccine used.
- For infants and young children receiving Nirsevimab (brand name Beyfortus), a single dose provides protection throughout the RSV season, as shown in a recent review article 2.
- For adults 60 years and older receiving either Arexvy or Abrysvo vaccines, protection has been demonstrated for at least one RSV season following vaccination, though studies are ongoing to determine if protection extends beyond this timeframe 3, 4.
- For pregnant women receiving the maternal RSV vaccine (Abrysvo), the antibodies passed to the baby provide protection for approximately 6 months after birth, as reported in a systematic review and meta-analysis 4.
Mechanism of Action
RSV vaccines work by stimulating the immune system to produce antibodies against the RSV F protein, which the virus uses to enter cells. These antibody levels naturally decline over time, which is why protection is generally limited to one season 5, 3.
Clinical Recommendations
Currently, recommendations don't include annual revaccination, but this guidance may evolve as more long-term data becomes available on the duration of immunity 2. The choice of vaccine and administration schedule should be based on individual patient risk factors and clinical guidelines.