Serological responses and clinical outcomes following a three‐dose primary COVID‐19 vaccine schedule in kidney transplant recipients and people on dialysis

Abstract

Abstract Objectives Despite vaccination strategies, people with chronic kidney disease, particularly kidney transplant recipients (KTRs), remained at high risk of poor COVID‐19 outcomes. We assessed serological responses to the three‐dose COVID‐19 vaccine schedule in KTRs and people on dialysis, as well as seroresponse predictors and the relationship between responses and breakthrough infection. Methods Plasma from 30 KTRs and 17 people receiving dialysis was tested for anti‐Spike receptor binding domain (RBD) IgG and neutralising antibodies (NAb) to the ancestral and Omicron BA.2 variant after Doses 2 and 3 of vaccination. Results After three doses, KTRs achieved lower anti‐Spike RBD IgG levels (P 1 g per day) and lower absolute B‐cell counts predicted poor serological responses in KTRs. ChAdOx‐1 vaccine type and higher monocyte counts were negative predictors in dialysis recipients. Among ancestral NAb seroresponders, higher NAb levels positively correlated with higher Omicron neutralisation (R = 0.9, P < 0.001). More KTRs contracted SARS‐CoV‐2 infection (14/30; 47%) than dialysis recipients (5/17; 29%) and had more severe disease. Those with breakthrough infections had significantly lower median interdose incremental change in anti‐Spike RBD IgG and ancestral NAb titres. Conclusion Serological responses to COVID‐19 vaccines in KTRs lag behind their dialysis counterparts. KTRs remained at high risk of breakthrough infection after their primary vaccination schedule underlining their need for booster doses, strict infection prevention measures and close surveillance.

Keywords

• antibody response
• COVID‐19 vaccine
• dialysis
• immune response
• kidney transplant
• SARS‐CoV‐2