In fact, Redfield himself said in the same CNN interview that he thought the virus had been circulating for months before we even noticed. It's not a quick jump. This is an extended time period that fits the idea. 2. Wildlife spillover. The idea is that there are billions of bats in China, with millions in contact with bats and other wildlife and, in some cases, humans every week. Viruses have many opportunities to jump. In its original form, it replicates inefficiently in humans. But even before it infects the first human, it has millions of chances to get better. Bats go out to forage and have a lot of contact with other animals such as pangolins, badgers, pigs and many others, and opportunistic viruses can infect these species. Coronaviruses mingle in bat colonies, giving them a chance to reorder their genes. They even mixed among individual bats: one bat was observed to carry several different coronaviruses. These viruses have time. Instead of one jump, they spend months moving from host to host, mutating as they move. Once inside the body, a version of the virus that has acquired mutations to improve its ability to infect human cells has the opportunity to replicate more frequently. They were quickly enough to infect cells that were apparently sick in humans, and we finally noticed a new disease. This happened during the same time period that Redfield said the virus was spreading.
https://www.scientificamerican.com/article/its-much-more-likely-the-coronavirus-came-from-wildlife-not-a-lab1/