Korean J Transplant.  2022 Nov;36(Supple 1):S320. 10.4285/ATW2022.F-4583.

Anti-spike antibody titer in kidney transplant recipients after the third dose of SARS-CoV-2 vaccination correlates with the incidence and severity of breakthrough infection during the Omicron surge

• Han A
• Min S
• Lee H
• Kim YC
• Kang HK
• Ahn YH
• Song EY
• Ha J

• KMID: 2535547
• DOI: http://doi.org/10.4285/ATW2022.F-4583

Abstract

Background
While a small number of studies have shown that the booster vaccination was able to provide additional serologic protection in transplant population, evidence on whether immunogenicity elicited provides actual protection from symptomatic Omicron infection is unclear.
Methods
CoVaKT was a prospective non-interventional study assessing the serologic efficacy and safety of a booster dose of SARS-CoV-2 vaccinations in COVID-19 infection nave renal transplant recipients (RTRs). To further evaluate the clinical ef-fectiveness of the vaccine, we collected data on the incidence and severity of subsequent breakthrough infections which all occurred during the Omicron surge and evaluated the association between post-booster anti-spike antibody level and clinical outcomes. Vaccine-induced SARS-CoV-specific antibody was quantified through Abbott SARS-CoV-2 immunoglobulin G (IgG) II Quant assay.
Results
A total of 287 RTRs who had standard doses of the COVID-19 vaccine were enrolled. After the booster mRNA vaccine dose, the seropositivity rate increased from 57.1% (164/287) to 82.2% (236/287). Median antibody titer also was significantly increased (62.3 to 1,382.8 AU/mL, P<0.01). Factors associated with negative antibody response were shorter duration since transplantation, lower hemoglobin, lower estimated glomerular filtration rate, high tacrolimus trough concentration, mycophenolate mofetil or mycophenolic acid use and having two doses of ChAdOX1-S during the primary vaccination. Sixty-five pa-tients (22.6%) had breakthrough COVID-19 infection within 4 months after the booster vaccination, of which 12 patients needed admission. The median time to infection was 83 days. Factors associated with infection in the multivariable logistic regression model were post-booster anti-spike IgG <400 AU/mL (odds ratio [OR], 3.55; 95% confidence interval [CI], 1.99–6.32; P<0.01), and having received living donor transplantation (OR, 1.97; 95% CI, 1.03–3.75; P=0.04). Low post-booster antibody level (IgG <200 AU/mL) was also a risk factor for severe disease (OR, 22.9; 95% CI, 2.27–231.6; P=0.01).
Conclusions
The COVID-19 mRNA booster vaccination was immunogenically effective in RTRs, and a higher anti-spike IgG level post-boost provided protection against both breakthrough infection and severe COVID-19 disease.