With Pfizer being the only company to have a third vaccine for use,  Guthrie County Public Health explains where the other companies are at in the process 

Public Health Director Jotham Arber says that Johnson and Johnson and Moderna  are doing larger studies and evaluating the science behind their products. Arber explains the process for Johnson and Johnson.

“Obviously the Johnson and Johnson was a single shot, it wasn’t a duel shot so they are trying to evaluate whether given that second would it put it in the category of a two shot series their trying to evaluate whether or not if that provides the clinical benefits they are looking for.”

Arber also states that Moderna is evaluating if their two shot series vaccine has longer protection than Pfizer’s vaccine. According to the Centers For Disease Control and Prevention, they will keep the public informed once more information is made available on the timeline for both companies.