World-first COVID vaccine booster randomized clinical trial in transplant patients proves third shot is very effective

The study enrolled 120 transplant patients between May 25th and June 3rd. None of them had COVID previously and all of them had received two doses of the Moderna vaccine. Half of the participants received a third shot of the vaccine (at the 2-month mark after their second dose) and the other half received placebo.
The primary outcome was based on antibody level greater than 100 U/ml against the spike protein of the virus. In the placebo group – after three doses (where the third dose was placebo), the response rate was only 18% whereas in the Moderna three-dose group, the response rate was 55%.