Le Duc said Shi 's work bat coronaviruses shown `` viruses exist nature , characteristics would allow transmissible among humans.The fact 're seeing today surprise folks working field . `` And although `` certainly , accidents happen laboratories , '' high level biocontainment Shi 's lab makes unlikely , said.BSL-4 labs stringent biosafety protocols , may include airflow systems , sealed containers , positive-pressure personal protective equipment ( PPE ) , extensive training , highly controlled access building.Having attended conferences Shi spoken work , Le Duc said highly reputable scientist . `` She 's always extremely open , transparent , collaborative , I reason doubt 's telling truth , '' said.Plus , Andersen said likelihood researcher becoming unknowingly infected coronavirus wearing full PPE going Wuhan market `` fleeting compared alternative hypothesis , humans , live amongst animals carrying viruses—bats , also many intermediate hosts—and , course , n't go around wearing PPE , naturally get contact viruses time . ''