MIT researchers have tweaked the design of mRNA-based covid-19 vaccines to produce a stronger immune response at a lower dose. They believe the technique might be applied to other RNA vaccines in development, including vaccines for cancer, and could make intranasal vaccination feasible.

The researchers used two strategies to boost the immune response. First, they engineered the mRNA to encode a protein called C3d, which binds to antigens and amplifies the antibody response to them. Next, the researchers modified the lipid nanoparticles used to carry the RNA into cells so that they stimulate immunity themselves instead of just delivering the vaccine. 

Mice injected with this vaccine produced 10 times more antibodies than mice given older covid vaccines, and it seemed to produce a similar response when delivered intranasally. 

“With intranasal vaccination, you might be able to kill covid at the mucous membrane, before it gets into your body,” says chemical engineering professor Daniel Anderson, the senior author of the study. “Intranasal vaccines may also be easier to administer to many people, since they don’t require an injection.” And because the modified vaccines are effective at a lower dose, they could be less expensive, which might also increase their use.