Low Prevalence Of Sars-Cov-2 Infection Among Asymptomatic Patients With Chronic Liver Disease In Osaka, Japan

Background: Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has recently become an emerging pandemic threat worldwide The prevalence of SARS-CoV-2 infection is relatively low in Japan;3,269 confirmed cases and 984 deaths were reported as of July 16, 2020 However, prevalence of subclinical SARS-CoV-2 infection remains to be determined In addition, whether it affects the clinical course of chronic liver diseases is still unknown Materials and Methods: A total of 1,462 serum samples were collected from patients without respiratory symptoms who visited outpatient clinic of Department of Hepatology in our hospital: 600 were taken before the SARS-CoV-2 endemic (Jun-Aug 2018 and Dec 2018-Feb 2019) as controls, and 862 were taken after SARSCoV- 2 was identified (Jan-Jun 2020) Of the 862 patients (63 ± 15 years old, 388 women and 474 men), 137 (15 9%) had HBsAg and 447 (51 9%) had anti-HCV;138 (16 0%) had HCC IgM and IgG antibodies against SARS-CoV-2 were detected in serum by using the SARS-CoV-2 IgM \u0026 IgG Quantum Dot Immunoassay (Mokobio Biotechnology R \u0026 D Center Inc ) Results: The positive rates of IgM and IgG anti-SARS-CoV-2 throughout the study period are shown in Table Even before the SARS-CoV-2 endemic, IgG anti-SARS-CoV-2 values were positive in 11/600 (1 8%) patients (median 0 16, range 0 10- 1 51), but IgM anti-SARS-CoV-2 were negative in all patients After SARS-CoV-2 identified, IgG anti-SARS-CoV-2 values were positive in 6/300 (2 0%) patients (median 0 26, range 0 14-1 08), and among them, 1/6 (17%) patient was also positive for IgM anti-SARS-CoV-2 (value, 4 38) between Janand Mar 2020 Moreover, between Apr and Jun 2020, IgG anti- SARS-CoV-2 values were positive in 10/562 (1 8%) patients (median 0 27, range 0 12-4 16), and among them, 6/10 (60%) patients was also positive for IgM anti-SARS-CoV-2 (median 0 66, range 0 32-1 36) Of the 7 IgM anti-SARS-CoV-2 positive patients (70 ± 8 years old, 4 women and 3 men), 2 (29%) had HBsAg, 4 (57%) had anti-HCV, and 1 (14%) had autoimmune hepatitis (receiving prednisolone);none had HCC or other types of cancer Comorbidities included hypertension in 2 patients, diabetes in 1 and rheumatoid arthritis in 2 (including 1 receiving prednisolone) No significant worsening of liver diseases was observed in any patients Conclusion: The false positive rates of IgG anti-SARS-CoV-2 were 1 to 2%, a little higher in patients with chronic liver diseases than the reported rates The results of IgM anti-SARS-CoV-2 testing suggested that subclinical SARS-CoV-2 infection is rare in Osaka, Japan, but the prevalence is increasing over time We found no evidence that subclinical SARS-CoV-2 infection was associated with progression of chronic liver diseases