An experimental vaccine is effective at preventing pneumonia in mice infected with the coronavirus.
The vaccine, which is made from a mild virus genetically modified to carry a key gene from the Covid-19 virus, is published in the journal Cell Host and Microbe.
“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,” researcher Michael S. Diamond of Washington University.
“Our vaccine candidate is now being tested in additional animal models with the goal of getting it into clinical trials as soon as possible,” Diamond said.
The study stated that the research team created the experimental vaccine by genetically modifying vesicular stomatitis virus (VSV), a virus of livestock that causes only a mild, short-lived illness in people.
They swapped out one gene from VSV for the gene for a spike from SARS-CoV-2, the virus that causes Covid-19. The hybrid virus is called VSV-SARS-CoV-2.
Spike protein is thought to be one of the keys to immunity against Covid-19.
The Covid-19 virus uses spike to latch onto and infect human cells, and the human body defends itself by generating protective antibodies targeting spike.
By adding the gene for spike to a fairly harmless virus, the researchers created a hybrid virus that, when given to people, ideally would elicit antibodies against spike that protect against later infection with the Covid-19 virus.
As part of this study, the researchers injected mice with VSV-SARS-CoV-2 or a lab strain of VSV for comparison.