Recent developments in the race to develop a COVID vaccine show promise, but the question remains – when will it become available to the general public? Dr. Sarah Gould returns for the fourth and final installment of our vaccine miniseries to examine where we stand with the development of COVID-19 vaccines and some lingering challenges that may hamper their final approval.     Acknowledgements: Hosted by: Chris Garcia Narrated by: Gina Mullane  Special thanks to:  Dr. Sarah Gould