Washington University School of Medicine in St. Louis reports an experimental vaccine is working at preventing pneumonia in mice infected with SARS-CoV-2, the vaccine behind the COVID-19 pandemic. The researchers developed the vaccine based on a mild genetically engineered virus designed to transport a SARS-CoV-2 gene.
Published in Cell Host and Microbe, Michael S. Diamond, MD, PhD and Professor of Medicine as well as a professor of molecular microbiology, pathology and immunology, reports that “unlike many of the other vaccines under development, this vaccine is made from a virus that is capable of spreading in a limited fashion inside the human body, which means it is likely to generate a strong immune response.” Although just at the proof of concept stage, Dr. Diamond continued explaining that this particular virus is highly replicable meaning that the ability to grow and scale up production, at least theoretically, could be compelling leading to attractive economics.
The Washington University School of Medicine, St. Louis team, including co-senior author Sean Whelan, PhD, and co-first authors Brett Case, PhD and Paul W. Rothlauf now investigates this virus further in preclinical animal models as they explore how to progress such a product to clinical trials.
Introduction to VSV-SARS-CoV-2
The team developed this preclinical stage vaccine by genetically modifying vesicular stomatitis virus (VSV), a virus of livestock that according to Washington University School of Medicine in St. Louis, triggering just a mild, short-lived illness in humans. In a basic engineering modification move the team replaced a gene from the VSV for the actual gene for spike from SARS-CoV-2. This hybrid virus developed in St. Louis is called VSV-SARS-CoV-2. As the spike protein is considered a target creating immunity against COVID-19 as the pathogen uses that spike to clasp onto and infect human cells, while the body seeks to generate protective antibodies targeting that spike. The researchers speculate that by genetically modifying and adding the spike gene to a relatively harmless virus, this hybrid result would trigger immunity from COVID-19.
Similar Approach for Ebola
Interestingly, Tamara Bhandari writes for Washington University School of Medicine, St. Louis that a comparable strategy was embraced with positive results for a virus developed via a derivation from VSV genetically modified with an Ebola virus gene. Now the author writes an Ebola targeted VSV-genetically modified product has been administered safely in Africa, Europe and North America: it was also used to end the outbreak in the Democratic Republic of the Congo.
Behind the Pack but…
With promising data and a brilliant team, they will need more to accelerate this effort. Many months behind the exiting COVID-19 experimental vaccine pack, at least six vaccines have reached final state testing and of course the U.S. government, including Dr. Anthony Fauci of the National Institute of Allergy and Infectious Diseases (NIAID) expect a mass vaccine ready for use early in the year. However, much is up in the air. There is certainly political pressure to report “good news” and although the sponsors are progressing now in Phase 3, the SARS-CoV-2 pathogen may morph hence rendering a vaccine not 100% effective. Moreover, a sizable part of the population may hold off on the “Vaccine 1.0 and await 6 to 12 months to determine which vaccine is truly safe or effective.” Moreover, Vaccine 2.0 could be superior and more economical leading to commercial opportunity despite lagging the current packs.
Michael S. Diamond, MD, PhD, the Herbert S. Gasser Professor of Medicine, and Professor of Medicine, professor of molecular microbiology, pathology and immunology
Sean Whelan, PhD, Marvin A. Brennecke Distinguished Professor and head of Development of Molecular Microbiology
Brett Case, PhD, postdoctoral researcher
Paul W. Rothlauf, graduate student