BackgroundPatients with rheumatic diseases (RD) have been excluded from SARS-CoV-2 vaccine trials, though data appear to show safety and efficacy, mostly evidence remains in mRNA vaccines. In our country, adenovirus-vector, inactivated and heterologous scheme vaccines are frequently used.ObjectivesTo describe the safety of SARS-CoV-2 vaccines in patients with RD from the national registry SAR-CoVAC and to assess sociodemographic and clinical factors associated to AE and disease flares after vaccination.MethodsAdult patients with RD who have been vaccinated for SARS-CoV-2 from de Argentine Society of Rheumatology Vaccine Registry (SAR-CoVAC) were consecutively included between June 1st and December 21st, 2021, This is a national multicentric observational registry that includes patients that have received at least one dose of any SARS-CoV-2 available vaccines in Argentina. Data is voluntarily collected by the treating physician. Naranjo scale was use to assess the association between the AE and vaccination.Homologous and heterologous schedules were defined according to whether both vaccines received were the same or different, respectively. Descriptive statics, Chi2 test, Fischer test, T test, ANOVA and multivariate regression logistic model were used.ResultsA total of 1679 patients, with 2795 SARS-CoV-2 vaccine doses were included. Vaccines more frequently used were: Gam-COVID-Vac (1227 doses, 44%), ChAdOx1 nCov-19 (872 doses, 31%), BBIBP-CorV (482 doses, 17%) and mRAN-1273 (172 doses, 6%). Altogether, 510 EA were experienced by 449 (27%) patients. Pseudo-flu syndrome was the most frequent (11%), followed by injection site reaction (7%). They were significantly more frequent after the first dose in comparison to the second one (13% vs 7% and 9% vs 5%, respectively, p<0.001 in both cases). All were mild or moderate and no patient was hospitalized due to an AE. One case of moderate anaphylaxis was reported by a patient who received Gam-COVID-Vac. No cases of vaccine-induced thrombotic thrombocytopenia were observed. There were 25 disease flares reported, 17 (68%) cases of arthritis. Among patients with two doses, those with heterologous schedule presented AE more frequent after the second dose (39% vs 17%).Total incidence of EA was 182.5 events/10 00 doses, it was significantly lower for BBIBP-CorV (105.9 events/1000 dosis, p<0.002 for all cases). The higher incidence of AE was observed for mRAN-1273 (261.6 events/1000 doses) and ChAdOx1 nCov-19 (232.8 events/1000 doses).Patients with AE were younger [mean 55 years (SD 14) vs 59 years (SD 14), p <0.010], not Caucasian ethnicity [48% vs 35%, p<0.001], had higher education level [mean 13.8 years (SD 4) vs 11.9 years (SD 5), p<0.001], were more frequently employed [54% vs 44%, p<0.001], lived mostly in urban area [99% vs 95% p <0.001, had more frequently dyslipidemia [38% vs 28% p 0.012], and less frequently arterial hypertension [49% vs 65%, p<0.001]. Systemic lupus erythematosus [11% vs 7%, p=0.039] and Sjögren syndrome [6% vs 1.8%, p<0.001] were more frequent among them, while non inflammatory diseases were less prevalent [19% vs 31%, p<0.001]. They were taking steroids [24 vs 18%, p=0.007], antimalarials [17% vs 10%, p<0.001] and methotrexate [41% vs 31%, p <0.001] more frequently.In the multivariable analysis, mRAN-1273 and ChAdOx1 nCov-19 were associated with AE, while BBIBP-CorV with lower probability of having one. (Figure 1)Figure 1.Variables associated with the development of AE. Multivariate logistic regression modelConclusionThe incidence of AE was 1825 events/1000 doses, were significantly higher for mRAN-1273 and ChAdOx1 nCov-19 and lower for BBIBP-CorV. Most common AE was pseudo-flu syndrome. Female sex, being younger, higher education level, ChAdOx1 nCov-19 and mRAN-1273 vaccines, the use of methotrexate and antimalarials were related of EA in patients with RD.References[1]Sattui SE et al. Early experience of COVID-19 vaccination in adults with systemic rheumatic diseases: results from the COVID-19 Global Rheumatology Alliance Vaccine Survey. RMD Open 2021;7.Disclosure of InterestsNone declared