How close are we to COVID-19 herd immunity?

As the COVID-19 pandemic continues around the world, we're hearing more about the concept of herd immunity. We wanted to dig into herd immunity and find out exactly what it is, how it works, and what happened in other places around the world that have tried to use herd immunity as a strategy without having a vaccine. Dr. Jason Diaz, Assistant Professor in the Integrated Science, Business and Technology Program at La Salle University joins KYW Newsradio In Depth to explain everything you need to know about herd immunity.