ObjectivesTo evaluate the distinct impact of disease modifying antirheumatic drugs (DMARD) combination and monotherapy in immune response to an inactivated SARS-CoV-2 vaccine in patients with rheumatoid arthritis (RA).MethodsThis phase 4 prospective study analysed seroconversion (SC) of anti-SARS-CoV-2 immunoglobulin G (IgG) and neutralising antibodies (NAb) induced by the inactivated vaccine (CoronaVac) in patients with RA in comparison to controls (CG). Disease activity and treatment were also assessed. Only participants with baseline negative IgG/NAb were included.ResultsPatients with RA (N=260) and CG (N=104) had comparable median ages (59 years (50–65 years) vs 58 years (49.8–64 years), p=0.483). Patients with RA had moderate but lower SC (61.8% vs 94.2%, p<0.001) and NAb positivity (45% vs 78.6%, p<0.001) in comparison to CG after full vaccination. Baseline disease activity did not influence immunogenicity (p>0.05). After multivariate analyses, factors independently related to reduced SC were: older age (OR=0.79 (0.70–0.89) for each 5-year interval, p<0.001), methotrexate (OR=0.54 (0.29–0.98), p=0.044), abatacept (OR=0.37 (0.19–0.73), p=0.004) and number of DMARD (OR=0.55 (0.33–0.90), p=0.018). Regarding NAb, age (OR=0.87 (0.78–0.96) for each 5-year interval, p=0.007) and prednisone >7.5 mg/day (OR=0.38 (0.19–0.74), p=0.004) were negatively related to the presence of NAb. Further comparison of SC/NAb positivity among RA treatment subgroups and CG revealed that methotrexate/tofacitinib/abatacept/tocilizumab use, in monotherapy or in combination, resulted in lower responses (p<0.05), while tumour necrosis factor inhibitor and other conventional synthetic DMARD interfered solely when combined with other therapies.ConclusionsPatients with RA under DMARD have a moderate immunogenicity to CoronaVac. We identified that nearly all DMARD combinations have a deleterious effect in immunogenicity, whereas a more restricted number of drugs (methotrexate/tofacitinib/abatacept/tocilizumab) also hampered this response as monotherapy. These findings reinforce the need of a broader approach, not limited to specific drugs, to improve vaccine response for this population.Trial registration detailsNCT04754698.