WASHINGTON : Scientists have genetically modified a "mild virus" which generates antibodies in humans just like the novel coronavirus, but without causing severe disease, an advance which they say will enable more labs across the world to safely test drugs and vaccine candidates against COVID-19.The researchers from the Washington University School of Medicine in St Louis in the US engineered the mildly infecting vesicular stomatitis virus (VSV) which virologists widely use in experiments by swapping one of its genes for one from the novel coronavirus SARS-CoV-2.According to the study, published in the journal Cell Host & Microbe, the resulting hybrid virus infects cells, and is recognised by antibodies in humans just like SARS-CoV-2, but.