ABO and Rh blood groups and risk of infection: systematic review and meta-analysis

Persons with non-O and Rh-positive blood types are purported to be more susceptible to infection, including SARS-CoV-2, but there remains uncertainty about the degree to which this is so for both non-viral and viral infections.

We systematically reviewed Embase and PubMed from January 1^st 1960 to May 31^st 2022. English-language publications were selected that separately investigated the relation between ABO and/or Rh blood group and risk of SARS-CoV-2 and non-SARS-CoV-2 infection. Pooled odds ratios (OR_p) and 95% confidence intervals (CI) were then generated for each.

Non-O blood groups had a higher OR_p for SARS-CoV-2 than O blood groups, both within 22 case-control studies (2.13, 95% CI 1.49- 3.04) and 15 cohort studies (1.89, 95% CI 1.56- 2.29). For non-SARS-CoV-2 viral infections, the respective OR_p were 1.98 (95% CI 1.49-2.65; 4 case-control studies) and 1.87 (95% CI 1.53-2.29; 12 cohort studies). For non-viral infections, the OR_p were 1.56 (95% CI 0.98-2.46; 13 case-control studies) and 2.11 (95% CI 1.67-6.67; 4 cohort studies). Rh-positive status had a higher OR_p for SARS-CoV-2 infection within 6 case-control studies (13.83, 95% CI 6.18-30.96) and 6 cohort studies (19.04, 95% CI 11.63-31.17), compared to Rh-negative persons. For Rh status, non-SARS-CoV-2 infections, the OR_p were 23.45 (95% CI 16.28-33.76) among 7 case-control studies, and 9.25 (95% CI 2.72-31.48) within 4 cohort studies. High measures of heterogeneity were notably observed for all analyses.

Non-O and Rh-positive blood status are each associated with a higher risk of SARS-CoV-2 infection, in addition to other viral and non-viral infections.