When the immune system is compromised, people rely on vaccines to eliminate and inactivate the threat. However, the process with which this happens is anything but simple. Dr. Christina Satterwhite joins us to explain how the immune system works and how vaccines target harmful pathogens in the second installment of our series on vaccines.Acknowledgements: Hosted by: Chris Garcia Narrated by: Gina Mullane  Special thanks to:  Dr. Christina Satterwhite