On Mar. 24, 2021, Virginia Tech researchers announced that their candidate Coronavirus vaccines, prevented pigs from becoming ill with a pig Coronavirus, porcine epidemic diarrhea virus (PEDV). The researchers published their findings in the preprint server BioRXIV.

The candidate coronavirus vaccines, created by Virginia Tech’s University Distinguished Professor X.J. Meng and UVA Health’s Professor Steven L. Zeichner, prevented pigs from being becoming ill with a pig coronavirus, porcine epidemic diarrhea virus (PEDV). The researchers have recently published their findings in the Proceedings of the National Academy of Sciences.

The new vaccine-production platform involved synthesizing DNA that directs the production of a piece of the virus that can instruct the immune system how to mount a protective immune response against a virus.

Their coronavirus vaccine offers several advantages that could overcome major obstacles to global vaccination efforts. It would be easy to store and transport, even in remote areas of the world, and could be produced in mass quantities using existing vaccine-manufacturing factories. The new vaccine-production platform involves synthesizing DNA that directs the production of a piece of the virus that can instruct the immune system how to mount a protective immune response against a virus.

That DNA is inserted into another small circle of DNA called a plasmid that can reproduce within bacteria. The plasmid is then introduced into bacteria, instructing the bacteria to place pieces of proteins on their surfaces. The technique uses the common bacteria E. coli.

One major innovation is that the E. coli have had a large number of its genes deleted. Removing many of the bacteria’s genes, including genes that make up part of its exterior surface or outer membrane, appears to substantially increase the ability of the immune system to recognize and respond to the vaccine antigen placed on the surface of the bacteria. To produce the vaccine, the bacteria expressing the vaccine antigen are simply grown in a fermenter, much like the fermenters used in common microbial industrial processes like brewing, and then killed with a low concentration of formalin.

The entire process, from identifying a potential vaccine target to producing the gene-deleted bacteria that have the vaccine antigens on their surfaces, can take place very quickly, in only two to three weeks, making the platform ideal for responding to a pandemic.