As of Sept. 24, there are 42 vaccines in clinical trials on humans. At least 92 others are being developed but have not yet gone to trial. For months, the world has tracked the progression of these vaccines closely, with the expectation that once one arrives on the market, we can finally start to go back to normal. But, is that true? Does the world really look much different with an effective vaccine? Guest: Dr. Paul Offit, professor of pediatrics at the Children's Hospital of Philadelphia. Host Celeste Headlee   Learn more about your ad choices. Visit megaphone.fm/adchoices