Introduction: The aim of the current study was to investigate the relationship between lung involvement of SARS-CoV-2 and antibody levels of COVID-19 patients 3 and 6 months from the disease. Methods: A total of 156 participants were divided into two groups, Group 1: lung involvement (LI)-positive and Group 2: LI-negative. Biochemical parameters and anti-SARS-CoV-2 IgG antibody levels were measured. Results: The results showed that mean levels of urea, LDH, CRP, ferritin, neutrophil count and D-dimer were significantly higher in the LI-positive group. In addition, mean antibody levels in the 3rd and 6th months were higher in the LI-positive group (p < 0.005). Discussion: High antibody levels in LI-positive patients correlated with some immunologic and biochemical parameters. Further studies should be performed to determine protective antibody levels against reinfection, how long protective titers last and the mechanisms by which COVID-19 symptoms, demographics and comorbidities may drive higher antibody levels.

Background: The study aimed to determine the antibody responses of hemodialysis (HD) patients receiving the second dose of inactivated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine (CoronaVac).Methods: Patients were divided into two groups according to the time elapsed since the second dose of SARS-CoV-2 vaccine: group 1 was 14-20 weeks after second dose of vaccine, and group 2 was 8-13 weeks. In addition, patients were divided according to their antibody (anti-spike IgG) response as inadequate < 0.2 µg /mL and adequate response ≥ 0.2 µg /mL. Factors such as age, dialysis vintage, diabetes mellitus and Kt/V which may affect response to SARS-CoV-2 vaccine were evaluated.Results: Out of 67 patients, according to exclusion criteria 30 patients were excluded. 52.7% and 33.3%patients had adequate response, in those groups, respectively. In the group 2, the age of those who did not have an antibody response was 65.0±10.4, while those with a response were 50.5±11.0 years old (p=0.015, 95% CI).In addition, one of our two patients in the group 1, who received four doses of 40 µgr recombinant hepatitis B vaccine and did not get anti-HBs antibody response (anti-HBs <10 IU/mL) was also unresponsive to the second dose of SARS-CoV-2 vaccine. Antibody responses to the SARS-CoV-2 vaccine in both groups were not different in terms of the compared characteristics of the patients (p>0.050).Conclusion: The second dose of SARS-CoV-2 vaccine responses in HD patients was analyzed and the positive effect of being relatively younger was determined 8-13 weeks after second dose.