MO827ASSESSMENT OF SARS-COV-2 ANTIBODIES IN PATIENTS ON HEMODIALYSIS
Authors: Taira Takayasu 
Published: May 2021

Abstract

Background and Aims
Strategies to minimize the risk of transmission of coronavirus disease 2019 (COVID-19) infection in hemodialysis (HD) patients have been rapidly implemented worldwide (Nature 16: 311, 2020). Serological testing of 356 HD patients revealed that 129 (36.2%) patients were positive for SARS-CoV-2 antibodies. Out of these 129 patients, 52 (40.3%) patients were asymptomatic (JASN 31:1969, 2020). In this study, we investigated the seroprevalence of SARS-CoV-2 antibodies in HD patients who were managed per Japanese Society for Dialysis-Therapy guidelines in the context of COVID-19.

Method
Study (1): A total of, 55 patients that underwent HD (41 males, 14 females; mean age: 66.3±12.8 years, HD duration: 72.2±68.4 months) between August 1 and December 14, 2020, were included. We measured SARS-CoV-2 antibodies with a fully automated cobas e801 analyzer using an Elecsys® Anti-SARS-CoV-2 electrochemiluminescence immunoassay (Roche Diagnostics) to qualitatively detect SARS-CoV-2 antibodies in human plasma. The Elecsys® assay uses a modified double-antigen sandwich immunoassay with recombinant nucleocapsid protein (N), which is geared towards the detection of late, mature, high-affinity antibodies independent of the subclass. Study (2): We tested the plasma of 8,982 adult with normal renal function for SARS-CoV-2 antibodies between July 1 and November 18, 2020.

Results
Study (1): Using serological testing, only 2 out of 55 (3.64%) HD patients tested positive for SARS-CoV-2 antibodies. In total 54 patients were asymptomatic during the study period and did not have a polymerase chain reaction (PCR) test. Only 1 out of the 54 (1.85%) patients that were asymptomatic had SARS-CoV-2 antibodies. Case 1 was an 89-year-old, male who had undergone HD for 53 months because of end stage kidney disease (ESKD) secondary to diabetic nephropathy. His blood type was O Rh (+). This patient tested positive for SARS-CoV-2 antibodies on August 11, 2020. Serological testing showed that this patient had an asymptomatic disease. Case 2 was a 74-year-old, male that had undergone HD for 62 months due to ESKD secondary to diabetic nephropathy. He was hospitalized because of bradycardia-tachycardia syndrome on November 14, 2020. On that day, his PCR test was negative. He underwent surgery to insert a cardiac pacemaker on November 18, and had a fever (37.7°C) on November 24. A chest CT scan revealed that he had bilateral lung pneumonia. On that day, his PCR test was positive. Blood tests showed that his white blood cell count was 4300/μL (lymphocyte 30.4%), and C-reactive protein (CRP) levels was 2.8 mg/dL. He was not treated with antiviral medication, the PCR test was repeated and was positive on December 4,7, and 9. However, his PCR test was negative on December 13. This patient tested positive for SARS-CoV-2 antibodies on December 14. He recovered from a COVID-19 infection 21 days after the onset of the disease. Study (2): Using serological testing, 47 out of 8,982 (0.52%) adults tested positive for SARS-CoV-2 antibodies. In Japan, the population of Kanagawa prefecture is 9,216,009. The number of PCR-confirmed patients with COVID-19 infection was 13,340 (0.14%) on December 6, 2020. The estimated number of asymptomatic SARS-CoV-2 infection was 47,923 (0.52%). The total estimated number of patients with COVID-19 infection was 61,263. In study 1, more than 90% of HD patients wear face masks, wash their hands, and maintain social distance of 2 m in dialysis facilities. Almost all patients avoided the three Cs (closed spaces with poor ventilation, crowded places with nearby people, close-contact settings, such as close-range conversations).

Conclusion
We found that Japanese patients on HD had a lower prevalence of SARS-CoV-2 antibodies compared to those in the United Kingdom. Serological testing identified HD patients with asymptomatic disease. Avoiding the ‘three Cs’ is very important in minimizing the risk of COVID-19 among HD patients.