The common goal of all vaccines developed against COVID‐19, although they have been designed with different methods, is to develop an effective immunity and antibody response against SARS‐CoV‐2. However, the postvaccination immune response and antibody levels differ between individuals. This study examined the relationship between postvaccine seropositivity rates, age, gender, smoking, and body mass index (BMI), and antibody titers. A total of 314 healthcare workers (HCW) who were not previously infected with COVID‐19 and who had received two doses of CoronaVac inactivated vaccine participated in the study. Seropositivity against the receptor‐binding domain (RBD) of the SARS‐CoV‐2 spike protein was measured from the participants 4 weeks after the second dose of vaccine using the electrochemiluminescence (ECLIA) method. In addition, the antibody developed against the nucleocapsid protein (NCP) was evaluated and compared using Elecsys Anti‐SARS‐CoV‐2 kit. One hundred and eighty‐one of the participants were female (57.6%) with a median age of 39 (interquartile range [IQR], 10) and 133 (42.4%) were male with a median age of 41 (IQR, 11). 99.6% of the volunteers developed seropositivity 4 weeks after the second dose of vaccine. It was also observed that the rate of RBD protein antibody titer was >250 U/ml in smokers, which is quite low compared to nonsmokers (p = 0.032), and that high RBD antibody titers were proportionally lower in obese participants, according to BMI values, compared to those with normal BMI (49.5% and 9.9%). It was observed that seropositivity developed in almost all participants after the CoronaVac vaccine. However, it was determined that the antibody titer measured varied depending on factors such as smoking, BMI, and duration.

Apoptosis is a main regulator in responses of cellular immunity throughout systemic viral infections. Perforin, soluble Fas ligand, caspase-3 and caspase-cleaved cytokeratin-18 (M-30) are mediators of apoptosis. The aim of this study is the evaluation of Crimean-Congo hemorrhagic fever (CCHF) disease changes in the levels of these apoptotic markers and the relation of these changes with disease severity. Forty-nine hospitalized children with CCHF and 36 healthy controls were enrolled in this prospective study. The CCHF patients were classified into 2 groups based on disease severity (severe group and nonsevere group). Demographic characteristics and clinical and laboratory findings of all patients were recorded on admission. Serum perforin, caspase-3 and soluble Fas ligand levels were found to be significantly higher both in the severe and nonsevere CCHF groups than the healthy control group (P < 0.05), but there was no significant difference in these apoptotic markers between severe and nonsevere CCHF groups (P > 0.05). In addition, serum M-30 levels did not differ significantly among all groups (P > 0.05). There was a positive correlation between serum values for perforin, caspase-3 and M-30 and the disease’s severity criteria such as aspartate aminotransferase and/or alanine aminotransferase. The serum levels of all these markers were negatively correlated with disease severity criteria such as the platelet count. In this study, we concluded that the interactions of cytolytic granules containing perforin and caspase cascade and Fas-FasL may play an important role in the pathogenesis of CCHF in children.