Kidney transplant (KT) waitlist candidates may have a higher rate of SARS-CoV-2 positivity than official government data indicate, according to investigators presenting at the virtual American Transplant Congress 2021.

Of 400 waitlist candidates who resided in Georgia counties with an above-average COVID-19 case rate in August 2020, 28 candidates tested positive for antibodies to SARS-CoV-2, yielding a 7% positivity rate. (Use of hemodialysis and peritoneal dialysis was comparable between KT candidates who tested positive and negative.)

COVID-19 rates among KT candidates in these counties were approximately 10-fold higher than statistics published by the Georgia Department of Public Health for the general population, Aileen C. Johnson, MD, and colleagues from Emory University in Atlanta, Georgia, reported. The official numbers might be attributable to insufficient testing or undercounting of asymptomatic infections, the investigators suggested. Alternately, KT candidates may be more susceptible to SARS-CoV-2 infection due to immune dysregulation, they stated.

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All 28 seropositive patients had SARS-CoV-2 antibodies for the duration of the 5-month study.

The investigators also reviewed panel reactive antibodies (PRA) test results from 15 seropositive candidates and found no changes.

“Our findings provide reassurance that hemodialysis is not exposing transplant candidates to greater risk of COVID-19 exposure,” Dr Johnson told Renal & Urology News. “Additionally, seroconversion – that is naturally acquired COVID-19 immunity – does not appear to be a risk factor for the development of donor specific antibodies to potential organ donors. Further monitoring of candidates after transplantation and immunosuppression is needed to determine optimal management in the setting of these additional exposures.” 

The Luminex-based assay detects antibodies against SARS-CoV-2 including full Spike, S1, S2, nucleocapsid, and receptor binding domain epitopes. It also detects antibodies against 4 common coronaviruses, SARS-1, and MERS. In 5 positive tests that were dismissed, investigators determined that patients had these other common coronaviruses.

“We were pleasantly surprised that all patients displayed SARS-CoV-2 antibodies throughout the duration of their follow-up,” Dr Johnson noted. “However, we encourage cautious optimism in interpreting these findings, since both the T cell response and the neutralizing effect of [COVID-19] antibodies are important, unmeasured factors that additionally contribute to the protective immune response.”


Johnson AC, Larsen CP, Gebel H, Bray R. COVID-19 in the kidney transplant waitlist population. Am J Transplant. 2021;21(suppl 3).Presented at the virtual American Transplant Congress, June 5-9, 2021. Abstract 59.