An investigation of the humoral immune response to mRNA COVID-19 vaccination with two doses versus three doses in Iraq/Baghdad

As a result of the SARS-CoV-2 epidemic, several vaccines against COVID-19 have been produced around the world. The BNT162b2 mRNA vaccine was the first approved vaccine because of its effectiveness in inducing a humoral immune response immediately after the second dose. However, it was determined that there was a decrease in the antibody level over time. The aim of this study is to compare the efficacy of the third dose of Covid-19 mRNA vaccines with the pre-mRNA-based Pfizer vaccine by detecting the level of post-vaccination serum anti-SARS-CoV-2 antibodies. The samples were collected form 120 individuals and after the second dose, the infected Covid-19 individuals were not included in the analysis has been excluded. According to the results obtained, no statistically significant changes were detected in HCT, Hb, Lymphatic %, Neutrophils %, Basophil %, Eosinophil % and LDH. However, WBC, Monocyte % and Platelets showed statistically significant changes (p< 0.05). In addition, Neutralizing antibody (Nab), hs-CRP, IgG and IgM showed statistically significant changes (p< 0.00). As a result, according to the data obtained from 120 people in Baghdad, it was determined that the third dose of BNT162b2 vaccine had positive effects on the humoral immune response.