CNN."It's not unusual for respiratory pathogens that are being worked on in a laboratory to infect a laboratory worker," he added.He offered no explanation for this idea other than to say as a virologist, he does not believe the virus could have been so contagious when it jumped directly from an animal to a person.Instead, he contends it was manipulated in a Wuhan research laboratory to become more contagious and then accidentally released by a worker in September or October 2019, a few months before coming to public attention.Redfield said that he thought it unlikely a disease that originated in bats - as many experts believe - so swiftly "became one of the most infectious viruses that we know in humanity for human-to-human transmission,".