Blood Type O Offers Defense Against COVID-19

People with gene variant chr3p21.31 found more likely to have serious respiratory symptoms when diagnosed with COVID-19
dna with blood background

A new study revealed COVID-19 presents with a wide range of severity, from asymptomatic in some individuals, to fatal in others. 

Based on a study of over 1-million research participants, these researchers report genetic and non-genetic associations with testing positive for COVID-19, respiratory symptoms, and hospitalization.

This non-peer-reviewed study published on September 7, 2020, strengthens the evidence for a role for ABO in COVID-19 host genetics. This study highlighted people with blood group ‘O’ seemed to test positive for COVID-19 less often than others, according to 23andMe’s data.

Whereas previous reports suggested COVID-19 protection was limited to the rhesus positive group23, this study’s data does not support that conclusion.

And, people who tested positive and had a gene variant, chr3p21.31, also seemed to be more likely to have serious respiratory symptoms when diagnosed with COVID-19.

The locus contains multiple genes (SLC6A20, LZFTL1, CCR9, CXCR6, XCR1, FYCO1) that could be functionally implicated in COVID-19 pathology.

A previous study published in the JAMA on June 17, 2020, also identified a 3p21.31 gene cluster as a genetic susceptibility locus in patients with COVID-19 with respiratory failure and confirmed a potential involvement of the ABO blood-group system.

Furthermore, this study identified risk factors for hospitalization including advancing age, male sex, elevated body mass index, lower socio-economic status, non-European ancestry, and pre-existing cardio-metabolic and respiratory conditions.

While non-European ancestry was found to be a significant risk factor for hospitalization after adjusting for socio-demographics and pre-existing health conditions, these researchers did not find evidence that these 2 primary genetic associations explain differences between populations in terms of risk for severe COVID-19 outcomes.

As of July 25, 2020, just over 1.05 million research participants took the COVID-19 baseline survey. Respondents were included in this analysis if they had consented to research and had a non-missing response to the question.

However, there are notable caveats to relying on self-reported data for a disease with lethal outcomes. Namely, the cases identified in this study were healthy enough to respond to the survey therefore are likely biased towards a healthier case population than otherwise exists. In addition, 23andMe research participants are a self-selected group and may not reflect the general population.

Note: All of the study authors identified as being part of 23andMe are current or former employees of 23andMe, Inc., and hold stock or stock options in 23andMe, and is an employee of GlaxoSmithKline and owns company stock.

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