Fast Five Quiz: Pediatric Respiratory Syncytial Virus Management

Asif Noor, MD


March 03, 2022

Currently, there are over 30 investigational RSV vaccine candidates in different phases of development. These vaccine candidates include live-attenuated, vector-based, particle-based, and subunit vaccines. Seven vaccine candidates are currently in phase 3.

Live-attenuated vaccines are not associated with enhanced RSV in RSV-naive populations after natural exposure. The quest for a safe and effective RSV vaccine endured a huge set back after a formalin inactivated (FI) RSV vaccine in 1966 was associated with enhanced respiratory disease. Many of these vaccinated children, when subsequently exposed to natural RSV infection by natural causes, developed the enhanced respiratory disease. Live-attenuated vaccines have the advantage of an easy intranasal route of administration and can invoke a host mucosal immune response even in the presence of maternal antibodies. However, tolerability and safety have historically been an issue with live-attenuated vaccines because there may be insufficient attenuation of the virus.

Vector-based vaccines that are currently under investigation have not been associated with enhanced disease. The immune response to vector-based vaccination has not been shown to interfere with maternal antibodies. However, vaccine recipients do have the potential to develop antivector antibodies, which could blunt the optimal immune response, particularly for booster vaccination doses.

Unlike live-attenuated vaccines, particle-based vaccines may be immunogenic across a broader range of age cohorts, including pediatric populations.

Vaccine development for RSV has been a global priority for the past several decades. However, with the recently increased prioritization of resources for COVID-19 vaccine development and the ramifications of social distancing, the results of these randomized controlled trials may be blunted or not reach statistically meaningful endpoints. In the near term, these vaccines are not likely to be available for preterm infants and those with underlying conditions. Thus, continued use of immunoprophylaxis in children who are eligible according to the current AAP guidelines probably will continue for some time. Alternatively, studies on long-acting investigational monoclonals have shown promising results in early clinical trials and may obviate the need of monthly injections.

Learn more about vaccine development for RSV.

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