Time‐dependent changes in the seroprevalence of COVID‐19 in asymptomatic liver disease outpatients in an area in Japan undergoing a second wave of COVID‐19

• Published in: Hepatology Research 2020-10, Vol.50 (10), p.1196-1200
• Main Authors: Suda, Goki, Ogawa, Koji, Kimura, Megumi, Maehara, Osamu, Kitagataya, Takashi, Ohara, Masatsugu, Tokuchi, Yoshimasa, Kubo, Akinori, Yamada, Ren, Shigesawa, Taku, Suzuki, Kazuharu, Kawagishi, Naoki, Nakai, Masato, Sho, Takuya, Natsuizaka, Mitsuteru, Morikawa, Kenichi, Sakamoto, Naoya
• Format: Article
• Language: English
• Subjects: Asymptomatic; Coronaviruses; COVID-19; Elecsys assay; Endoscopy; IgG; Immunoglobulin G; liver disease; Liver diseases; Nosocomial infection; Pandemics; Public health; SARS‐CoV‐2; SARS‐CoV‐2COVID‐19; Serology; Severe acute respiratory syndrome coronavirus 2
• ISSN: 1386-6346; 1872-034X
• DOI: 10.1111/hepr.13551

Aim Coronavirus disease 2019 (COVID‐19) is a serious public health concern, with unclarified prevalence in Japan. Concomitant liver disease could increase the severity of COVID‐19 disease, and chronic liver disease patients sometimes require frequent admission and gastrointestinal endoscopy. Thus, clarifying the prevalence of asymptomatic COVID‐19 in outpatients with liver disease is essential for preventing nosocomial infections. We aimed to clarify the time‐dependent changes in COVID‐19 seroprevalence in liver disease outpatients, who were asymptomatic for COVID‐19, in an area of Japan experiencing a second wave of COVID‐19. Methods We included the preserved sera of 100, 300, and 300 consecutive liver disease outpatients, who were asymptomatic for COVID‐19, from May 2019, March 2020, and May 2020, respectively. The sera were analyzed immunochromatographically to detect immunoglobulin G against severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) (KURABO) and by Elecsys Anti‐SARS‐CoV‐2‐assay (Roche Diagnostics). Results Analysis of 100 cases from May 2019, before COVID‐19 became pandemic, revealed that the specificity of immunochromatographic tests and Elecsys were 98% (95% confidence interval [CI], 93–99.8%) and 100% (95% CI, 97–100%), respectively. Analysis of 300 cases from March 2020 revealed a seroprevalence of 0.3% (1/300; 95% CI, 0–1.8%) for COVID‐19 by Elecsys Anti‐SARS‐CoV‐2 assay. Analysis of 300 cases from May 2020 revealed a seroprevalence of 0% (0/300; 95% CI, 0–1.0%). Conclusions The Elecsys Anti‐SARS‐CoV‐2 assay has high specificity. The cumulative seroprevalence of COVID‐19 by the Elecsys Anti‐SARS‐CoV‐2 assay in outpatients with liver disease in Sapporo, who were asymptomatic for COVID‐19, was 0.17% (1/600; 95% CI, 0.0–0.9%) until May 2020.