Design of clinical studies to evaluate immune responses induced by RSV vaccination in elderly and immunosuppressed individuals

Respiratory syncytial virus (RSV) is a leading cause of respiratory infections, particularly in infants, the elderly, and immunosuppressed individuals, resulting in significant hospitalizations.

Despite the global demand, vaccine development has faced challenges, particularly regarding the specificity of antibody (Ab) responses required for protection.

Previous RSV vaccine trials in young children led to enhanced disease due to non-neutralizing Abs, highlighting the complexity of effective vaccine design. Last year, two protein-based RSV vaccines were approved focusing on the elderly, with an mRNA vaccine forthcoming.

Although Sweden´s Public Health Agency recommends vaccination for individuals over 75, uptake has been low due to costs.

Moreover, there are gaps in understanding the immune responses elicited by these vaccines, especially concerning differences between the vaccines and their effects on immunosuppressed patients in which the vaccines have not yet been thoroughly tested.

We propose a national collaborative clinical study to evaluate immune responses in younger (60-65-years old) vs elderly (80+ years old) nursing home residents as well as in immunosuppressed stem cell transplant patients.

Our team, comprising clinicians and immunologists with expertise in Ab response characterization, is uniquely positioned to conduct such studies, which is crucial for optimizing the use of the new RSV vaccines and understand immune correlates of protection.