Increasing evidence points to host genetics as a factor in COVID-19 prevalence and outcome. CCR5 is a receptor for proinflammatory chemokines that are involved in host responses, especially to viruses. The CCR5-delta32 minor allele is an interesting variant, given the role of CCR5 in some viral infections, particularly HIV-1. Recent studies of the impact of CCR5-delta32 on COVID-19 risk and severity have yielded contradictory results. This ecologic study shows that the CCR5-delta32 allelic frequency in a European population was significantly negatively correlated with the number of COVID-19 cases (p=0.035) and deaths (p=0.006) during the second pandemic wave. These results suggest that CCR5-delta32 may be protective against SARS-CoV-2 infection, as it is against HIV infection, and could be predictive of COVID-19 risk and severity. Further studies based on samples from populations of different genetic backgrounds are needed to validate these statistically obtained findings.

Department of Medical Biology and Genetics Faculty of Medicine University of Rijeka Rijeka Croatia

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