COVID-19 vaccination in patients with CKD in New Zealand (C-VAK NZ): lower rate of seroconversion in transplant versus dialysis patients
Helen Pilmore1,2,4, Paul Manley1,4, Ian Dittmer1,4, Jafar Ahmed1,4, Andrew Pilmore1,4, Elizabeth Curry4, Germaine Wong3, David Semple4.
1Auckland Renal Transplant Group, Auckland City Hospital, Auckland, New Zealand; 2Medicine, University of Auckland, Auckland, New Zealand; 3Western Renal Servcie, Westmead Hospital, Sydney, Australia; 4Renal Medicine, Auckland City Hospital, Auckland, New Zealand
Introduction: Patients with kidney failure on dialysis and with kidney transplant are at least five times more likely to die from COVID-19 than patients without kidney disease. Yet, vaccine efficacy in these patients is unclear. Aims: We examined the immunogenicity of BNT162b2 COVID-19 vaccination in Covid-naïve dialysis and transplant recipients using Spike antibody levels.
Methods: Kidney transplant and dialysis patients in a single centre underwent spike antibody testing using the Roche elecsys SARS-CoV-2 Nucleocapsid Total Antibody Assay prior to vaccination, at 1 and 3 weeks after the second vaccination dose and at 1 month and 3 months after the third vaccination dose.
Results: 388 patients underwent vaccination, and all had antibody levels tested (162 Kidney Transplant, 226 Dialysis). None had Covid-19 infection prior to vaccination. Mean Covid spike antibody levels were higher in dialysis patients than transplant recipients at week 1 (183.9U/ml versus 39.3 U.ml) and week 3 (217.0U/ml versus 55.3U/ml) (p<0.001 for both comparisons) (Figure 1). Three weeks after vaccination, 32% of transplant recipients had seroconverted compared to 96% of dialysis patients. Transplant recipients were younger than dialysis patients and less co-morbid. There was no association between patient age, sex or time from transplantation with seroconversion rates. However transplant recipients on mycophenolate ≥ 1g/day had lower spike antibody levels (mean 17.1U/ml) than those on < 1g/day (52.0U/ml) or no mycophenolate (139.0U/ml, p<0.0001). After the third vaccination, 76% of transplant patients had seroconverted however mean antibody levels were lower at one month (142.3U/L) compared to dialysis patients (244.0U/ml. p<0.0001), 98% of whom had detectable spike antibody.
Figure 1: Covid Antibody Levels pre and post vaccination in Transplant and Dialysis Patients
Conclusions: Seroconversion rates after 3 doses of the Pfizer SARS-CoV-2 vaccination are lower in kidney transplant recipients than dialysis patients. Vaccination prior to transplantation and booster doses in transplant recipients are recommended.
