The trial aimed to compare the immunogenicity of two COVID-19 booster vaccines, BNT162b2 and JNJ-78436735, in solid organ transplant recipients, a population at high risk for severe COVID-19 outcomes. The termination of the trial due to recruitment difficulties may indicate challenges in engaging this specific patient population, which could affect the commercial viability of both vaccine candidates in this niche market. The results may provide insights into the efficacy of different booster strategies, potentially influencing future vaccination guidelines and market positioning for both sponsors.