Investigational Vaccine Could Provide Broad Protection Against Coronaviruses

April 21, 2021
Skylar Kenney, Assistant Editor

The vaccine that could provide protection against existing and future strains of the coronavirus disease 2019 (COVID-19).

An investigational vaccine that could provide protection against existing and future strains of the coronavirus disease 2019 (COVID-19), as well as other coronaviruses, has shown promising results in early animal testing, according to a study published in the Proceedings of the National Academy of Sciences. This vaccine would cost around $1 per dose.

The researchers—professors Steven L. Zeichner, MD, PhD, at UVA (University of Virginia) Health; and Xiang-Jin Meng, MD, PhD, at Virginia Tech—created vaccines that prevented pigs from being becoming ill with, porcine epidemic diarrhea virus (PEDV), a pig model coronavirus. According to the study authors, this vaccine was developed using an innovative approach that might one day open the door to a universal vaccine for coronaviruses, including coronaviruses that previously threatened pandemics or those that cause some cases of the common cold.

The approach taken by the researchers targets a part of the spike protein of the virus, the "viral fusion peptide," which is essentially universal among coronaviruses and has not been observed to differ at all in the many genetic sequences of SARS-CoV-2. They created 2 vaccines, 1 designed to protect against COVID-19, and another against PEDV. Studying PEDV in pigs allowed the researchers to observe the ability of the vaccines to offer protection against a coronavirus infection in its native host. Previous models used to test COVID-19 vaccines study SARS-CoV-2 in non-native hosts, such as monkeys, hamsters, or mice, that have been genetically engineered to enable them to be infected with SARS-CoV-2.

According to the study, both the PEDV and SARS-CoV-2 vaccines protected the pigs against illness caused by PEDV. These vaccines did not prevent infection, but protected the pigs from developing severe symptoms, similar to observations made when primates were tested with candidate COVID-19 vaccines. The vaccines also primed the immune system of the pigs to mount a much more vigorous immune response to the infection. The researchers say that vaccines protection against disease caused by PEDV and having the immune system primed to fight the disease makes it reasonable to believe that the COVID-19 vaccine would also protect humans against severe COVID-19 disease.

The studied vaccine is produced by injecting E. coli bacteria with a DNA plasmid designed to replicate a small piece of the virus. An innovation in this process involves removing many of the bacteria’s genes, which includes genes that make up part of its exterior surface or outer membrane. This 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, according to the researchers.

“Killed whole-cell vaccines are currently in widespread use to protect against deadly diseases like cholera and pertussis. Factories in many low-to-middle-income countries around the world are making hundreds of millions of doses of those vaccines per year now, for a $1 per dose or less,” said Zeichner, in a prepared statement. “It may be possible to adapt those factories to make this new vaccine. Since the technology is very similar, the cost should be similar too.”

Additional testing, including human trials, will be required before the COVID-19 vaccine can be approved by the FDA or other regulatory agencies.

REFERENCE

New COVID-19 vaccine may offer broad protection from coronaviruses [news release]. EurekAlert; April 19, 2021. Accessed April 20, 2021. https://www.eurekalert.org/pub_releases/2021-04/uovh-ncv041621.php