North Americans began receiving the CoVID-19 vaccine this week, less than a year after the novel coronavirus was identified. That accelerated timeline is a remarkable scientific achievement. And horse people may be gratified to learn about the small but critical role that horses played in making that happen.

In 2005, a vaccine developed by Fort Dodge Animal Health to protect horses from West Nile Virus (WNV) was an early first step in the technology utilized to create the CoVID-19 vaccine. That vaccine was the first world’s first DNA vaccine approved for human or animal use.

Conventional vaccines use a killed or inactive form of an entire virus to “teach” the body how to build an immune response to fight it. DNA vaccines, in contrast, use only small portion of genetic material from a virus. That material is injected into recipient, whose cells then transcribe the DNA into messenger RNA (mRNA), that create distinct but harmless proteins that the stimulate the body’s immune response, defending against the entire virus. Gene-based vaccines generally stimulate more thorough immune responses and are faster to develop and manufacture than conventional vaccines.

Click here to read how coronavirus may have circulated among the equine population for a decade before 2020. 

The CoVID-19 vaccine is the first in the next generation of genetic vaccines. “The CoVID-19 vaccine developed by Pfizer is a novel mRNA vaccine. It is similar to, though not the same as, the original Fort Dodge DNA vaccine for the prevention of West Nile Virus infection in horses,” explains David Horohov, PhD, director of the Gluck Equine Research Center at the University of Kentucky. “In the case of the DNA vaccine, the DNA is incorporated into cells which then transcribe it into mRNA, which is eventually translated into proteins. The immune response is then directed against those proteins. The CoVID-19 mRNA vaccine starts the process earlier by being directly translated into proteins once incorporated into the cell.” 

The DNA vaccine against WNV was very effective, says Horohov, but the company elected to shift to a more conventional vaccine once that version was given regulatory approval. However, the place of that first WNV vaccine in the history of immunology shouldn’t be overlooked, says Horohov: “The WNV DNA vaccine developed for horses was very much a beginning step for the development of the type of vaccine technology being used for CoVID-19. It provided important evidence that nucleic acid-based vaccines were safe and efficacious. We should all be proud of the role the horse has played in this new vaccine.”

Click here to read an in-depth exploration of the threat coronaviruses can pose to horses.

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