In a Brief Communication, published July 29, 2021, in Transplant Infectious Disease, a team of physician-scientists at University of California San Diego School of Medicine found that solid organ transplant recipients who were vaccinated experienced an almost 80% reduction in the incidence of symptomatic COVID-19 compared to unvaccinated counterparts.
“Persons who have received an organ transplant are considered to be at increased risk for COVID-19 and for a severe outcome because their immune systems are necessarily suppressed to ensure their transplants are successful and lasting,” said Saima Aslam, MD, Professor of Medicine at UC San Diego School of Medicine and Medical Director of the Solid Organ Transplant Infectious Disease Service at UC San Diego Health. “These findings offer strong evidence that getting vaccinated provides significant protection.”
The researchers examined clinical data from the UC San Diego Health transplant registry from January 1, 2021 through June 2, 2021, encompassing 2,151 solid organ transplant recipients, including kidney, liver, lung and heart. Of this total number, 912 patients were fully vaccinated and 1,239 were controls (1,151 were unvaccinated and 88 partially vaccinated). Nearly 70 percent of the vaccinated patients received the mRNA-1273 vaccine (Moderna).
During the study period, there were 65 diagnosed cases of COVID-19 among the organ recipients: four among fully vaccinated individuals and 61 among the controls (two involving partially vaccinated individuals). There were no deaths among the breakthrough COVID-19 cases, but two among the 61 control cases.
The authors noted several limitations of the study: It involved retrospective data collection, was a single center report and there was potential for under-reporting by some patients of their vaccination status. They also noted that almost half of the study population was not vaccinated during the study period, underscoring the need for improved outreach to the transplant community regarding the benefits of COVID-19 vaccination.