The only study focusing SARS-CoV-2 mRNA vaccine in systemic lupus erythematosus(SLE) observed a moderate response but the sample size precluded an accurate analysis of the effect of individual drugs. We therefore assessed immunogenicity of an inactivated SARS-CoV-2 vaccine(Sinovac-CoronaVac) and the influence of different medications in SLE. Safety was also assessed.
We conducted a prospective controlled study of 232 naïve-SLE patients and 58 naïve-controls(CG) who were vaccinated with two doses of Sinovac-CoronaVac with a 28-days interval(D0/D28). Immunogenicity analysis at D0/D28 and D69 included anti-SARS-CoV-2 S1/S2 IgG seroconversion(SC), and neutralizing antibodies(NAb) positivity. The influence of individual drugs on immune response and safety were assessed.
Patients and CG were well balanced for age(p=0.771). At D69 SLE patients showed a moderate SC(70.2% vs. 98.1%,p<0.001) and moderate frequency of Nab positivity(61.5% vs. 84.6%,p=0.002), although both lower than CG. Factors associated with lower SC in univariate analysis at D69 were prednisone(OR:0.215[0.108-0.427];p<0.001) and mycophenolate mofetil(MMF)(OR:0.201[0.107-0.378];p<0.001), whereas hydroxychloroquine(HCQ) use led to a 2.5 increase in SC(p=0.011). SLE patients under HCQ-monotherapy had similar SC to CG at D69 (100% vs. 98.1%,p=1.000). In multivariate analysis, prednisone and MMF use were independently associated with lower SC(p<0.001) and NAb positivity(p<0.001). Safety analysis revealed no moderate/severe adverse events.
Sinovac-CoronaVac has a moderate immunogenicity in naïve-SLE patients with an excellent safety profile. We further demonstrate that HCQ may improve SC, whereas prednisone and MMF had a major deleterious effect in vaccine response reinforcing the need to investigate the role of temporary MMF withdrawn or a vaccine-booster dose[clinicaltrials.gov #NCT04754698].