Anti-SARS-CoV-2 immunogenicity decay and incident cases six months after Sinovac-CoronaVac inactivated vaccine in autoimmune rheumatic diseases patients: phase 4 prospective trial

We provide novel data on anti-SARS-CoV-2 immunogenicity decay and incident cases six months after the 2nd dose of Sinovac-CoronaVac inactivated vaccine(D210) in 828 autoimmune rheumatic diseases(ARD) patients compared with 223 age/sex-balanced control group(CG). From D69 to D210, anti-S1/S2IgG positivity and GMT reduced 23.8% and 38% in ARD(p<0.001/p<0.001) and 20% and 51% in CG(p<0.001/p<0.001). From D69 to D210 NAb positivity and activity declined 41% and 54% in ARD(p<0.001/p<0.001) and 39.7% and 47% in CG(p<0.001/p<0.001). Multivariate logistic regression analysis showed that male(OR=0.56;95%CI0.40-0.79;p<0.001), prednisone(OR=0.56; 95%CI0.41-0.76;p<0.001), anti-TNF(OR=0.66;95%CI0.45-0.96;p=0.031), abatacept(OR=0.29; 95%CI0.15-0.56;p<0.001) and rituximab(OR=0.32;95%CI0.11-0.90;p=0.031) use were associated with a substantial reduction on IgG response at D210 in ARD patients. A decrease of COVID-19 cases(from 27.5 to 8.1/100 person-years;p<0.001) occurred during the study despite the Delta variant spread. In conclusion, after 6-months of Sinovac-CoronaVac 2nd dose, immunogenicity of ARD patients was markedly reduced, particularly in males and those under prednisone/biological therapies, without a concomitant rise in COVID-19 cases(NCT04754698).