Dr Steven Pergam Discusses NCCN's Preference for mRNA Vaccines

Steven Pergam, MD, MPH, director of infection prevention at Seattle Cancer Care Alliance and infectious disease physician at Fred Hutchinson Cancer Research Center, discusses the National Comprehensive Cancer Network's (NCCN) preference for mRNA vaccines and how they work differently.

Transcript:

The NCCN preference for mRNA vaccines aligns with data presented at ASH by the Leukemia and Lymphoma Society. Can you discuss why the mRNA vaccines offer better protection for these patients?

I can't speak to why it's better. It's always a little bit of a nuance of how these vaccines work and the specifics about particular populations, and they do seem to be a particularly powerful method for delivering this particular approach to COVID. The data and how it works basically is, these are coated in a lipid particle with an mRNA component in it that basically connects and goes into a cell. That mRNA goes into the cell, that mRNA then transcribes the mRNA components and makes it into a protein production in the cell, and that protein is the spike protein that's put onto the surface of the cell. It doesn't actually cause infection in the other components that we worry about, but it allows the immune system to create a response to that spike protein, and that has the ability to create an immune response, which is what we need to be prepared for the next time it sees that. The way it's been described by some people, it's like a wanted poster: It's there, you see it, and then it disappears, but everyone remembers what was on that wanted poster. On that spike protein, that immune system is now ready for that individual when it comes through. I think it's an important mechanism of how it works.

The adenovirus vectors are a little bit different. They use a similar process to get information in, but it uses a viral vector to sort of use that same mechanism instead of doing it through that lipid particle. They're a little bit different in how they work. It's unclear exactly—I can't speak to why one is necessarily better than the other—but definitely the mRNA vaccines appear to have a more robust immune response, at least by antibody levels, particularly, within the immunosuppressive population. Now, there may be some advantages to adenovirus vaccines, there may be some more longer term T-cell responses, but I think we're going to need to continue to study this and understand how they each work and where specific niches may work better than others.