Association of ABO blood groups with SARS-CoV-2 infection in Saudi Arabia based on a systematic review and meta-analysis.

Although previous studies and meta-analyses have suggested modest and population-dependent associations between ABO blood groups and susceptibility to SARS-CoV-2 infection, findings have remained inconsistent across different geographic regions. We synthesized data from nine studies conducted in Saudi Arabia between 2020 and 2024 to define national patterns. Eight datasets with extractable data contributed 7650 laboratory-confirmed cases to quantitative analyses. Group O accounted for the largest proportion of infections (random effects estimate 41.7%, 95% CI 38.0-45.6), followed by group A (27.8%, 95% CI 25.6-29.9) and group B (21.2%, 95% CI 18.0-24.6). Group AB represented the smallest fraction (6.4%, 95% CI 3.7-9.9). Substantial heterogeneity was observed across all blood groups (I² 72.1-96.5%) yet leave-one-out analyses confirmed stable pooled estimates. Statistical assessments provided no evidence of publication bias. The pooled distributions closely mirrored background ABO frequencies in the Saudi population, indicating that ABO-related differences in infection susceptibility are modest relative to epidemiologic and demographic factors.