Why Coronavirus Drugs, Vaccine Require More Time

When a pathogen jumps from animals and starts infecting people for the first time, it’s especially worrisome because most humans won’t have immunity to it yet. It’s usually the case, too, that doctors lack specific vaccines to prevent such an agent and medicines to treat it. So it is with the Covid-19 coronavirus that emerged late last year from China and is spreading rapidly around the world. No preventives or drugs have yet been approved against the virus, though scientists and companies are r