The impact of ABO blood group on COVID-19 infection risk and mortality: A systematic review and meta-analysis.
Level 3 - non-randomized controlled study
Systematic review and meta-analysis of observational studies
PubMed 33309392 · doi:10.1016/j.blre.2020.100785
What was done
The authors conducted a systematic review and meta-analysis across seven databases to evaluate whether ABO and Rh blood groups are associated with COVID-19 susceptibility and mortality. Out of 715 retrieved articles, 10 met inclusion criteria and were analyzed.
What was found
Blood group A (OR = 1.33, 95% CI 1.14 to 1.56) and blood group B (OR = 1.06, 95% CI 1.00 to 1.13) were associated with higher risk of COVID-19 infection, whereas blood group AB showed no significant association (OR = 1.07, 95% CI 0.88 to 1.30). Blood group O had a lower infection risk (OR = 0.71, 95% CI 0.60 to 0.84). Rh-positive status was reported with OR = 1.22 (95% CI 0.99 to 1.50). A meta-analysis of 5 studies linked blood group A to increased mortality (OR = 1.25, 95% CI 1.02 to 1.52).
Why it matters
This review aggregates early pandemic evidence suggesting host genetic ABO antigens correlate with differential susceptibility and clinical outcomes in SARS-CoV-2 infection.
Limits
The analysis is restricted to 10 observational studies (and only 5 for mortality). Mild publication bias was present. The abstract describes Rh-positive risk as statistically significant despite the 95% CI crossing 1.0 (0.99 to 1.50). Total participant sample size and adjustment for potential demographic or clinical confounders are not reported in the abstract.
Cited by
- supports A study investigating blood types and COVID-19 susceptibility found that blood group A is associated with a higher risk of infection, whereas blood group O is associated with a lower risk compared to non-O groups.