Background:  In our study we aimed to evaluate links of plasma alpha-1 antitrypsin and vitamin D with the risk COVID-19, and whether it explained the higher incidence of COVID-19. Background: The pandemic COVID-19 was generated by severe acute respiratory syndrome [SARS] coronavirus (CoV2). A fast viral broadcasting leads to an unexpected increase of the number of cases in the world. Like the SARS -CoV2 infection case report the italian alpha 1 antitrypsin registry conclusions demonstrated an adjacent geographic spreading of positive cases. The highest infected rates were demonstrated in peoples deficient with alpha-1 antitrypsin (AAT). Methods: One hundred and eight person with mean age 49 years, from them 54 patients (33.3% male and 66.6 female) had COVID-19 infection and 54 heathy person. alpha-1 antitrypsin (AAT), vitamin D and C-reactive protein (CRP) checks were done for all of them. Results: Regarding the AAT there was a highly significant difference(p<0.05) among the groups where the average of the concentration in patients lower than that in healthy 0.99 (mg/dl)  and 4.33(mg/dl) spontaneously, also there was a highly significant difference(p<0.05) between the two groups regarding to vitamin D level that in patients 9.97 ng/ml lower that in healthy persons 34.22 ng/ml. While the average of CRP 119.43 µg/ml in infected persons and 6.33 µg/ml in non-infected persons with a highly significant difference (p<0.05). Conclusion: There was an association between COVID-19 infection with the levels of alpha-1 antitrypsin, vitamin D, CRP.