Progress towards an RSV vaccine

Can you tell me about some recent progress towards developing a vaccine for RSV?

With the COVID-19 pandemic, there has been a lot of activity in the development of new respiratory vaccines. Even prior to the outbreak of COVID-19, there was already some significant progress being made in this area. Now multiple pharmaceutical companies are in the late stages of development for an RSV vaccine with several also developing one for older members of the population.

What challenges are involved with the development of RSV vaccines?

I think there are several challenges associated with the space of RSV itself. A significant barrier has been the identification and optimisation of an antigen for RSV vaccine development. RSV is covered with a fusion protein which can be in two different confirmations: considered pre-fusion and post‑fusion conformation. We know that the post‑fusion confirmation is the more stable form, but the antibodies and immune responses that are elicited against this form of the protein are not particularly immunogenic or protective. The pre-fusion form is very unstable, but there is a stronger, more protective, immune response that is generated against this form.

This has been a real challenge in vaccine development because…