The pandemic controlling COVID-19 can cause the deaths of more than 4 million worldwide. Recently the production of the more effective vaccine genetically modified is the suitable solution for managing acute respiratory syndrome, SARS-CoV-2 was a talented emergency use license by FDA by a company of Pfizer-BioNTech (BNT162b2) mRNA the CRP and D dimer important blood markers for diagnosis and severity of this disease. The specific antibody SARS-CoV-2 IgG was the measurement titer after (14-20). After the intake first dose of vaccine by VIDAS® (BioMérieux, Marcy-L'Etoile, France), all volunteers have done screening examination by rapid test for detection not exposure to the previous infection, who had negative to SARS-CoV-2 IgG, after the second dose of vaccine, the specific IgG examination by using ELFA technique. CRP and D-dimer were used to monitor the blood markers to assess any side effects (side effects of the vaccine on the lung inflammatory and clotting system), measured after 48h of taking the vaccine in both doses. Ninety-four were included in this study (54 female and 40 male) and divided into two age groups. All the subjects had SARS-CoV-2 IgG after (10 and 20) days following the first dose and (10 and 20) days following the booster dose. The results were shown a non-significant difference in age between males and females. The mean value of the IgG titer against CoV antigen after 2nd dose of immunization is significantly higher than the corresponding value after the 1st dose. There is a non-significant correlation between the ages of immunized subjects with the IgG titer after receiving the second dose of the mRNA vaccine. The titer of IgG increased after the 2nd dose of vaccination while the C-reactive protein significantly decreased. The Pfizer mRNA vaccine gives an excellent active immune response to produce IgG after the booster dose, and results have not recorded any effect of the vaccine on the activity of blood inflammatory markers. Keywords: COVID-19; immune response; mRNA vaccine; C-reactive protein, D-dimer, anti-SARS-CoV-2 IgG.