Background/Aim: Patients with rheumatic disease are at high risk of infection complications, and vaccines are essential to prevent these diseases. Moreover, biologic disease-modifying/targeted synthetic anti-rheumatic drugs (b/tsDMARDs) have been shown to reduce the immunogenicity of vaccines, although their effectiveness, side effects, and effects on disease activity are not yet clear. In this study, we aimed to investigate the incidence of post-vaccine side effects, disease exacerbation, and COVID-19 infection despite vaccination in patients with inflammatory rheumatic disease; the difference in vaccination effects between patients who received and did not receive b/tsDMARD treatments. Methods: Patients received b/tsDMARD (i.e., biologic group (BG)) (n = 194) who were admitted to the rheumatology outpatient clinic, were included in this study. All patients with inflammatory rheumatological disease, who did not receive b/tsDMARD (n = 185), but who applied to the rheumatology outpatient clinic during this time, were included in the non-biologic group (NG). Patients followed were included and evaluated cross-sectionally. Clinical and demographic characteristics, as well as type of COVID-19 vaccination, post-vaccine side effects, COVID-19 infection status before and after vaccination, and post-vaccine rheumatological disease exacerbation, were also evaluated. Results: In BG, 92.2% of patients were vaccinated, but for NG, 82.7% were vaccinated against COVID-19 patients with BG, 46.2% were vaccinated with CoronaVac vaccine alone, 51.4% with Pfizer/BioNTech BNT162b2 vaccine alone, and 37.4% with a combination of CoronaVac and BNT162b2 vaccines. In the NG, 53.8% of patients were vaccinated with CoronaVac vaccine alone, 48.6% with BNT162b2 vaccine alone, and 36.2% with a combination of CoronaVac and BNT162b2 vaccines. There was a significant difference between groups, according to vaccine types (P = 0.040), as this difference was due to a larger number of patients vaccinated with the CoronaVac + BNT162b2 combination for BG. Adverse effects were detected in 99 patients (55.9%) with BG and 95 patients (62.5%) with NG post-vaccination. There was no difference between BG and NG vaccines (CoronaVac, BNT162b2, or their combination) for adverse effects (P > 0.05 for all). The vaccine with the most common adverse events was BNT162b2, for both BG and NG. The most common side effect was arm pain, significantly higher in BG (P = 0.014). Fever and rash were more common for NG (P = 0.017). Disease exacerbation was not observed with BG, whereas it was detected in 5 (1%) patients for NG that was different (P = 0.021). SARS-COV-2 infection was also significantly less common for BG vs. NG (15.3% vs. 20.3%) (P = 0.017). Despite COVID-19 vaccinations, 56 patients with BG and 62 patients with NG had COVID-19 (P = 0.005). Conclusion: Standardized vaccination comparisons could not be achieved, as patients using b/tsDMARD were vaccinated for fewer COVID-19 infections. Additionally, COVID-19 vaccines are well-tolerated in patients with rheumatological disease, with vaccine-related disease activity at 1%, only seen in those not using b/tsDMARDs.