Apparently, the shots may keep coming—especially for the immunocompromised—as the Centers for Disease Control and Prevention (CDC) updated their guidelines. The CDC considers this fourth shot an actual “booster.” As it turns out, the CDC suggests that those with immunocompromised scenarios are essentially considered a different cohort than all else. Their third vaccine dose isn’t a booster but rather an “additional dose” with the same amount of dosage as the previous jabs.

While it’s not apparent what clinical trials have led to this decision, the immunocompromised fourth dose is now classified as a booster. This seems to be a lot of shots in a particular inoculation period. The recommendation of the fourth booster at greater than six months post the third jab applies to those individuals 18 and up that are “moderately to severely immunocompromised” who have completed the vaccine series from Pfizer, Moderna, or Johnson and Johnson.