Ask DerrickTo view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 video06/01/2020June 1, 2020When we have a vaccine, how can we provide enough shots to inoculate everyone? Is there a difference between PCR tests and ELISA tests? DW’s science correspondent Derrick Williams answers questions about the coronavirus pandemic.https://p.dw.com/p/3d6zEAdvertisement