One difference is that J&J has been tested for only one shot and AZ is tested for two shots. Also the amount of vaccin you get shot in your arm could be differe

One difference is that J&J has been tested for only one shot and AZ is tested for two shots. Also the amount of vaccin you get shot in your arm could be different. The clotting incidents between the two are certainly different, AZ has much more at the moment.