Clinical trial resultsThe Pfizer/BioNTech and Moderna vaccines use a novel mRNA approach. Nanoparticles, or fat bubbles, deliver bits of viral genetic material that encode instructions for making the SARS-CoV-2 spike protein, which the coronavirus uses to enter human cells.
When injected into a muscle, the cells produce the protein, triggering an immune response. The mRNA degrades quickly in the body and it does not interfere with human genes.
The Pfizer/BioNTech vaccine was tested in a phase 3 clinical trial that enrolled a diverse population of more than 43,000 volunteers, including some in the Bay Area.
Participants were randomly assigned to receive two injections of the vaccine or a placebo spaced three weeks apart.The vaccine was 95%.