SARS-COV-2 VIRAL LOAD IN PATIENTS WITH AUTOIMMUNE RHEUMATIC DISEASE, A RETROSPECTIVE COMPARATIVE STUDY

Background Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral load and its impact on disease outcome in patients with autoimmune rheumatic disease (ARD) are lacking. Also, whether patients with ARD receiving immunomodulators have different viral loads compared to the general population is unknown. Objectives To compare the viral load of SARS-CoV-2 and its trending between patients without and with ARD. Methods Retrospectively, patients with ARD infected with SARS-CoV-2 were matched by age and sex at a ratio of 1:2 to patients without ARD and not receiving immunosuppression or immunomodulator drugs. Viral load was determined by the cycle threshold (CT) value measured by a number of platforms: (a) Automated Platforms - the Roche Cobas 6800 system using the Cobas SARS-CoV-2 Test targeting the E and orf1a/b genes (Roche, Switzerland) and the Xpert Xpress SARS-CoV-2 targeting the E and N genes (Cepheid, USA); (b) Manual platforms - EZ1 (QIAGEN, USA), QIAsymphony (QIAGEN, USA), and Bioneer ExiPrepTM 96 Virus DNA/RNA kits Catalogue No K4614 (Bioneer, South Korea) extraction with thermal cycling using TaqPath™ PCR COVID-19 Combo Kit targeting the N, S and orf1a/b genes (Thermo Fisher Scientific, USA) on ABI 7500 thermal cyclers. Independent samples t-test was used to compare the mean CT values of the study groups at baseline and at 5 subsequent intervals (1 – 5.9, 6 – 11.9, 12 – 17.9, 18 – 23.9 and 24 – 30 days). Results Mean age (SD) of 197 cases and 420 controls were 45.2 (11.8) and 44.1 (12.3) years, respectively. Females were predominant in both groups 60% vs. 52%, P=0.053. The most common ARD was rheumatoid arthritis in 82 cases (41.6%), followed by spondyloarthropathy in 33 (16.8%) and systemic lupus erythematosus in 31 (15.7%). Of the cases, 67% were on conventional synthetic disease modifying anti-rheumatic drugs (DMARDs), 15.2% on biological DMARDs and 4.6% patients were on rituximab. The mean CT values was significantly lower in the ARD group at baseline and persisted till day 24. Table 1. demographic characteristics and comparison of the mean CT values in the study groups at baseline and at different intervals with the corresponding OR (95% CI) Case (N=197) Control (N=420) OR (95% CI) Mean (SD) age, years 45.2 (11.8) 44.1 (12.3) 1.008 (0.994–1.022) Sex, female N (%) 120 (60.9%) 221 (52.6) 0.713 (0.505–1.006) Mean (SD) CT values at Baseline 22.9 (5.5) 30 (5.2) 0.799 (0.745–0.858 ) 1 – 5.9 days 22.1 (4.6) 25.7 (6.3) 0.901 (0.842–0.963 ) 6 – 11.9 days 26.9 (4.9) 31.5 (3.9) 0.802 (0.724–0.888 ) 12 – 17.9 days 29.6 (4.1) 32.3 (3.2) 0.827 (0.743–0.921 ) 18 – 23.9 days 32.1 (4) 32.9 (2.5) 0.903 (0.728–1.119) 24 – 30 days 31.2 (1.2) 32.7 (2.6) 0.824 (0.589–1.151) Conclusion Compared to patients without ARD, the viral load of SARS-CoV-2 in patients with ARD is significantly higher at baseline testing and persists till day 24. This finding may indicate that patients with ARD are at higher risk of severe SARS-CoV-2 infection and prolonged potential transmission. Clinical outcome correlation is needed. References None Disclosure of Interests None declared