Aim:
Background: COVID-19, which manifested as acute respiratory distress syndrome, has affected millions of people worldwide. Aims: to find any association between specific ABO blood groups and FUT2 secretory status and COVID-19 in a sample of Iraqi dentists.

Material and methods:
Materials and methods: For each participant, a questionnaire including demography, COVID-19 status, blood grouping, and RH factor, with chemo-sensitive symptoms was recorded. The saliva samples were collected and DNA was extracted from leukocytes. Sequencing of molecular detection of the FUT2 gene by real-time PCR and the data was done, whilst drawing the phylogenetic tree.

Results:
Results: Out of 133, most of the dentists were female 61%, most of which, were below the age of 35 years. Blood group O was the most predominant amonge study participants (40%), followed by B, A, and AB, with (90%) of them were RH+. All blood grouping and RH factor were high significantly associated with COVID-19 infection and its frequency (p<0.001). A significant association between smell dysfunction and infected blood group A and RH+ (p =0.044, 0.038) while taste dysfunction was negatively and significantly correlated with AB group (r=-0.73; p=0.008). The FUT2 secretor showed a significant association with COVID-19 infection and frequency. The majority of COVID-19-infected participants experienced a significant loss of both smell and taste with fast recovery within 2 weeks.

Conclusions:
Conclusion: The COVID-19 infection susceptibility and reinfection are associated with FUT2 secretory status and greatly associated to olfactory and gustatory sense loss.