ABSTRACT Background: This study aimed to assess the immunoglobulin G (IgG) antibody response rate in emergency department (ED) healthcare workers (HCWs) and potential adverse effects after CoronaVac vaccination. Methods: All included HCWs were grouped based on the previous history of coronavirus disease 2019 (COVID-19) and the number of vaccinations. Furthermore, the IgG antibody response was evaluated based on the sex and smoking status of HCWs. Those with a cut-off index of ≥1.00 after vaccination with CoronaVac were considered to have had COVID-19 and had an adequate humoral response. Results: Among 224 ED HCWs, 18% experienced the adverse effects of CoronaVac vaccine, the most prevalent being pain in the injection site. The IgG antibody response rate was 20% after the first dose of vaccine, while the response rate increased to 90% after the second dose. Female HCWs had higher IgG response rates compared with male HCWs (53.8 [15.9-147.0] vs 31.2 [4.5-124.0]). Non-smokers had higher IgG response rate compared with smokers (49.0 [11.5-160.5] vs 23.1 [7.4-98.5]). Conclusion: A single dose of CoronaVac does not produce a sufficient antibody response; hence, two doses are recommended. Men have a lower IgG response compared with women. Smokers had a lower IgG response rate compared with non-smokers. Therefore, it may be necessary to carefully assess the humoral responses of men and smokers when implementing a community vaccination program.

SUMMARY OBJECTIVE: The objectives of this study were to identify predictors of mortality in young adult patients with coronavirus disease 2019 and to assess the link between blood type and mortality in those patients. METHODS: This multicenter retrospective study, which was conducted in seven training and research hospitals in Istanbul, involved young adults who aged ≥18 and <50 years and hospitalized with coronavirus disease 2019. RESULTS: Among 1,120 patients, confusion at admission (p<0.001) and oxygen saturation (p<0.001) were significantly predictive factors of mortality. Blood type O was significantly associated with mortality compared to those discharged from the hospital (p<0.001). Among co-morbidities, the most reliable predictive factors were cerebral vascular disease (p<0.001) and chronic renal failure (p=0.010). Among laboratory parameters, high C-reactive protein (p<0.001) and low albumin (p<0.001) levels were predictors of mortality in young adult patients with coronavirus disease 2019. CONCLUSIONS: SpO2 at admission was the best predictor of mortality in young adult patients with coronavirus disease 2019. The mortality rate was increased by cerebral vascular disease and chronic renal failure. Also, high C-reactive protein and low albumin levels were predictive factors of mortality. Moreover, blood type O was associated with a higher mortality rate than the other types.