Severe Acute Respiratory Syndrome Coronavirus 2 Antibody Response After Heterologous Immunizations With ChAdOx1/BNT162b2 in End-Stage Renal Disease Patients on Hemodialysis

Abstract

The Korean government decided to schedule heterologous vaccinations on dialysis patients for early achievement of immunization against Coronavirus disease 2019(COVID-19). However, the effects of heterologous immunizations in hemodialysis (HD) patients are unclear. One hundred (HD) patients from Gangdong Kyung Hee University Hospital and Kyung Hee Medical Center and 100 hospital workers from Gangdong Kyung Hee University Hospital were enrolled in this study. The HD patients received the mixing schedule of ChAdOx1/BNT162b2 vaccinations at 10-week intervals, while hospital workers received two doses of ChAdOx1 vaccines at 12-week intervals. Serum IgG to a receptor-binding domain (RBD) of the S1 subunit of the spike protein of SARS-CoV-2 was measured 1 month after the first dose, 2 months and 4 months after the second dose. The median [interquartile range] anti-RBD IgG was 82.1[34.5, 176.6] AU/ml in HD patients and 197.1[124.0, 346.0] AU/ml in hospital workers (P < 0.001) after the first dose. The percentage of positive responses (IgG > 50 AU/ml) was 65.0% and 96.0% among the both group, respectively (P < 0.001). The anti-RBD IgG levels increased significantly by 2528.8 [1327.6, 5795.1] AU/ml with a 100.0% positive response rate in HD patients 2 months after the second dose, which was higher than those in hospital workers 981.4[581.5, 1891.4] AU/ml (P < 0.001). Moreover, anti-RBD IgG remains constantly high, and positive response remains 100% in HD patients 4 months after the second dose. This study suggests that heterologous vaccinations with ChAdOx1/BNT162b2 can be an alternative solution on HD patients for early and strong induction of humoral response.

Keywords: BNT162b2; COVID-19; ChAdOx1; anti-RBD IgG; hemodialysis; heterologous vaccination.

Figure 1

Comparison of antibody response between HD patients and hospital workers (A) Comparison of antibody levels following the first and second shot of vaccine between HD patients and hospital workers. (B) Comparison of antibody levels 2 month after the second shot of vaccine between younger and older HD patients (Age cut-off was 60 years). *P < 0.05, Dotted lines in (A) and (B) indicate the manufacturer’s pre-specified thresholds: anti-RBD IgG ≥ 50. Solid lines indicate median and interquartile range. m, months; w, weeks; ns, not significance.

Figure 2

Comparison of decay rate of anti-RBD IgG after second dose of vaccine between HD patients and hospital workers through nonparametric mixed models for exponential distribution. Red line = HD patients, with formula [Anti-RBD IgG = e^{(8.40-0.09*weeks after second vaccine)}]. Blue line = hospital workers, with the formula [Anti-RBD IgG = e^{(8.40-0.07*weeks after second vaccine)}].