[Blood groups and SARS-CoV-2 in health professionals from a single center]

The possibility that the blood group (BG) predisposes to SARS-CoV-2 infection is controversial.

To compare the prevalence of BG, anti-IgG SARS-CoV-2, and more frequent symptoms in convalescent health personnel vs controls prior to vaccination.

Analytical cross-sectional design of cases and controls, which included health personnel, from March to June 2020, confirmed with (polymerase chain reaction) PCR-SARS-CoV-2 and negative controls with PCR and anti-IgG-SARS-CoV-2. Participants were questioned concerning symptoms and BG was determined. It was used descriptive statistics and comparative analysis with chi squared, Fisher's exact test, Student's t, and Mann Whitney's U tests.

Of 218 workers, 102 (46.8%) were confirmed cases for SARS-CoV-2 (convalescent) and 116 controls. The distribution of BG was similar between cases and controls, being BG-O + the most frequent (52.9%). The risk of becoming infected by SARS-CoV-2 for BG-O compared to BGNo-O showed a lower trend (odds ratio [OR] 0.725, 95% confidence interval [95% CI] 0.416-1.261, p = ns). The BG-A (28.4%) compared with BG-No-A (71.6%) showed a trend of increased risk in BG-A (OR 1.523, 95% CI 0.818-2.837, p = ns). The presence of SARS-CoV-2 IgG antibodies was 85% in the convalescent group.

The prevalence of infected was proportionally higher for BG-A and lower for BG-O. About 15% did not develop SARS-CoV-2 antibodies after overcoming COVID-19 disease.