Discussion
ADVERSE EVENTS
This was a randomized controlled trial comparing BNT162b2 vs. JNJ-78436735 as a third dose after completion of two doses of BNT162b2 in SOT recipients. Similar to previous randomized controlled trial (At the time of our trial, there were two studies assessing the immunogenicity of mixing method in SOT recipients. One single center randomized controlled trial, conducted by Schwaighofer et al. (There are several limitations in this current study. Sample size was never achieved due to the challenges of persuading patients to possibly receive different vaccines based on randomization. Of note, the majority of our recipients had received the third dose at the time of enrollment. In addition, the prior vaccines could have been administered pre- or post transplantation; 34% of participants were vaccinated before transplant. Thus, we cannot conclude whether results are comparable between those vaccinated pre- and post-transplantation. In this study, we are limited to the use of surrogate marker, not the incidence itself. We included not only seronegative but also seropositive recipient at the time of the third dose vaccination in order to most accurately reflect our current population. We tried to address this limitation by calculating GMT. Lastly, our follow up consisted of 1 month duration making challenging to capture late occurring adverse events, along with concluding that IgG positivity 30 days post third vaccine dose properly reflect long term immunogenicity in transplant recipients. This warrants longer follow up for future studies.In conclusion, we conducted a patient-blinded, randomized controlled trial comparing BNT162b2 vs. JNJ-78436735 vaccine for the third dose after two doses of BNT162b2 COVID-19 vaccines in SOT recipients. We found similar immunogenicity using both vaccination strategies. Even though the primary outcome was not achieved due to small sample size being underpowered, larger studies will need to be performed to draw conclusion. Further investigation is needed to understand the optimal method of COVID-19 vaccination in this vulnerable group of patients. Also, further studies need to be conducted to determine duration of this immunogenicity.We sincerely thank for the significant support when conducting this project by Luke Preczewski, Lissett Moni, Jose A. Portogues and whole kidney transplant team in Miami Transplant institute, Jackson Health System.