Viruses That Are More Likely to Cause Pendemics

People are concerned that these viruses that we make might escape the laboratory and cause pendemics, which would be quite counterproductive. I wanted to kind of get a clearer handle on what the potential risks are from this potential pandemic enhancement research. And it seemed to me that there's either two or three categories, and i wasn't sure a the first category is the accidental leak of a apathagin that has been engineered to be more transmissible or more deadly.