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A forthcoming study from genetic testing giant 23andMe shows that a person’s genetic code could be connected to how likely they are to catch Covid-19 — and how severely they could experience the disease if they catch it. It’s an important confirmation of earlier work on the subject.

People whose blood group is O seemed to test positive for Covid-19 less often than expected when compared to people with any other blood group, according to 23andMe’s data; people who tested positive and had a specific variant of another gene also seemed to be more likely to have serious respiratory symptoms.

The study, which was released on a preprint server and which has not yet been peer-reviewed, could extend and confirm earlier work on the subject; 23andMe’s study relied on a larger dataset than earlier work and included a more diverse set of participants, the company said. Experts who aren’t affiliated with 23andMe praised the study design and the work.


“They clarify further what our data could only vaguely hint at,” said Tom Hemming Karlsen, a physician at Oslo University Hospital who published an article in the New England Journal of Medicine on genetic links with Covid-19 severity in June, and who was not associated with 23andMe’s work.

But the outside experts also cautioned that the research won’t change treatment decisions.


“It doesn’t have practical implications. There’s no treatment decisions that will be made from it — it’s just an interesting finding,” said Jennifer Lighter, a pediatrician and epidemiologist at NYU Langone who was not involved in the research.

Unlike the study Karlsen and his colleagues ran, which only included people with severe Covid-19 symptoms, 23andMe included people who had both mild and severe cases — which allowed them to draw stronger conclusions, Karlsen said.

The company’s study participants are also more diverse than Karlsen’s, which only studied people in Spain and Italy. However, the 23andMe study’s demographics still don’t fully reflect the population of the United States. A little more than 11% of the people in 23andMe’s studies said they were Latino; less than 3% said they were Black. (Latinos represent about 16% of the U.S. population, while Black people account for about 13% of the population.)

Both Karlsen and 23andMe’s team found that the genes that code for a person’s blood type seemed to be linked to whether a person would test positive for Covid-19; another section of chromosome 3 — referred to in both papers as chr3p21.31 — seemed to be linked to how severe a person’s response would be to a Covid-19 infection.

Janie Shelton, a senior scientist at 23andMe and a lead author of the paper, and her colleagues noted that genetic associations did not seem to explain all the differences between populations; public health experts have noticed that people of color seem to be particularly at risk for Covid-19 due to some of the direct and indirect health effects of inequality and discrimination.

Both studies suggested one gene found in that area on chromosome three — SLC6A20 — might be particularly related to worse outcomes; however, it’s not yet clear how a particular gene could make a meaningful difference in a person’s response to an infection.

Both 23andMe and Karlsen ran the same kind of genetic analysis — a genome-wide association study. This particular method, which tries to find similar patterns in the genetics of people with a particular condition, has significant limitations. Scientists have suggested that the method is most useful when used to analyze hundreds of thousands of genomes.

For most scientists, getting that many samples would be difficult and expensive. But 23andMe has an obvious advantage — it has already sequenced more than 12 million people, according to the company’s website; over a million people agreed to participate in the company’s Covid-19 study.

“I do think that because of the power of our large sample size, we were able to detect that association pretty strongly,” said Shelton.

Without a clear understanding of which genes matter — and why — the impact of genetic studies on Covid-19 treatment plans will be limited.

“We’d have to find out why it’s significant — is it significant because it’s affecting blood clotting?” Lighter asked. “Unless we find out why there’s a difference, we wouldn’t target therapies or [adjust] a risk category.”

  • What exactly would be considered the direct and indirect qualities of health because of “inequality and discrimination” on “people of color” (newsflash: we are ALL “people of color”, unless you want to refer to white people as translucent since we are the only ethnicity able to blush and see blood in the face and chest. That would be fine with me to label me as “translucent”, I rather like that term. When speaking in terms of color, white encompasses ALL colors whereas black is the absence of color.) I can’t believe people can’t even read an article about blood type without reading about so called “inequality and discrimination”. It’s all so tiresome.

    • @ Tiffany Kintz –
      QUOTE, “… speaking in terms of color, white encompasses ALL colors, whereas black is the absence of color.”

      That’s only accurate when you discuss the spectrum of visible light – & ethereal and angelic as any one person might be, humans are not made up of visible light beams.
      We are opaque flesh, with a skin that covers our muscles, organs, bony skeletons, blood vessels, & other tissues.

      When we speak of pigment & solid bodies, white is absence of pigments, & black is a mix of all colors – the exact opposite of the color spectrum of “white” light, such as daylight, as seen by human eyes with normal AKA average color vision.

      There are any number of metrics that show higher morbidity & mortality to all non-whites (anyone not of European descent) in the US.
      Black & brown skinned women are more likely to die or have serious complications, during pregnancy or childbirth. Black & brown skinned diabetics are more likely to go blind, or have a limb amputated, vs “whites”. Black & brown skinned heart attack & stroke patients are more likely to die vs “whites”; every one of these reflects a systemic difference in access to care, early vs later Dx, & treatment options offered.
      They are data – not opinion; & in my opinion, we can, & should, change these facts by improving healthcare – not only for black & brown skinned citizens, but for poor citizens & the elderly, no matter what color their skin might be.
      There is no reason that black women should die far more often than “whites” after a Dx of breast cancer; these outcomes are intolerable, just as redlining entire neighborhoods is, used to prevent “people we don’t want” getting bank loans & mortgages.
      Black & brown skinned citizens also pay higher interest rates on autos, even with the same credit score – this is pure theft. We need to address these inequities, & more – our nation is approaching a crisis, with profound differences between the few HAVES, & the many, many HAVE NOTS.
      Wealth has never been “equitably” distributed, but no one should need to work 3 full time jobs to be able to afford basic housing & food. It’s insane.

  • This just proves that when you offer up your blood it is being used for more than you are told. When you go to the Dr. for any reason there is always a need to take blood samples. Maybe to find out what diseases are more effective or ineffective against what blood types. They already know what blood types are predominant in each race, but what a great way to get people to voluntarily give their DNA and pay for the testing mind you, especially since it has been proven that those tests are hardly accurate, what else is it being used for, hopefully it doesn’t show up at a crime scene.

  • To Shelton. Skin color has nothing to do with keeping clean and protecting yourself. Neither does poverty. The only “discriminating” the virus is doing is targeting the elderly and those immuno compromised.
    -Tired of illogical cliches
    Blessings to all from someone in poverty in America

  • I have also researched. I found families that survived the black plague in Europe have less illnesses. Black population might have been far enough away to avoid it. As well as Asian. There fore they did not develop antibodies . And are susceptible to many newer viruses.
    So people that survived due to herd immunity. Came to the Americas. Then other populations south america, islands, we’re exposed and those generations acquired anibiodies. The people furthest back on genetic lines, before black plague survived worse plagues.

    I would suspect norweigns, , Angola Saxon some mongols may have immunity to all. Interesting blood type worst. What blood type least ??

    Good example native Indian populations. No exposures. So years ago pirates etc had this disease and killed off whole populations. Ex Aztec as malasia???

    Question would the bones of past cultures expose this disease. Is it dangerous to bring up old bones that had typhoid, plagues?

  • I am wondering if being rh negative or rh positive has any affect on contracting the virus.. I’m O- and have no signs of covid but when the H1-N1 hit the US I was 7 months pregnant and first in my county to test positive along with my 2 very young boys. I’m curious and wish I knew everything about my blood type..

  • Some blaming systematic racism 🤦🏻‍♀️🤦🏻‍♀️🤦🏻‍♀️ Such BS! Who is telling you to eat what you do? Who is keeping you from taking care of your own health? Is someone forcing you to go to McDonald’s for a Big Mac?

    • @ Raquel,
      depending upon where a person lives (what city & which neighborhood within that city, or which state & what county), GROCERY STORES may be few & far between, or even outside the resident’s local area.
      There are entire sections of cities with no grocery stores whatever, that have a liquor store on every other block, a 7-11 or other convenience store between the liquor stores, & a fast-food joint every half mile or less.
      So yes – what you can eat is restricted in many ways.

      How much money do you have?
      Fruit & veg cost much more than fast foods; soda is cheaper than bottled water or juices.
      For any woman over 35, HOW MUCH she drinks daily of carbonated beverages is her biggest risk factor for osteoporosis – Coke, Pepsi, & even Perrier won’t tell consumers that tidbit!

      If someone lives in a “food desert” without any nearby grocery stores, eating a decent diet gets very, very complicated.
      Walking down the street to the nearby convenience store & trying to find the least-junky food, or going to a neighborhood fast-food joint, may be the only “cheap” & easy options.
      But it costs your health, in the long term – a very expensive price, & essentially punishment, for all those who live in areas with cheaper housing, but no grocery.

      If you don’t have a car, & must use public transit, & either carry or cart your groceries back home, shopping is an effort – if the grocery store is also miles away, it adds a lot of time, traveling to it & returning.
      If you live in a food desert & have young children, leaving them at home while you go buy food may not be an option – so the kids must come along.
      Now, you have to pay their fare(s) in addition to your own, both ways – on that bus, trolley, or subway, plus manage your purchases & mind the kids. In most cities & towns, any child over 30-inches tall pays full fare – that adds up fast.

      You can see why it’s often cheaper, & certainly simpler, to take the whole family to Burger King or KY Fried Chicken, or just order a couple of delivery pizzas, & get 2 liters of free Coke, as a bonus.

      For folks living in areas with local grocery stores, good nutrition habits are much easier, & more affordable.
      For folks living in good deserts, there’s a heavy premium on eating healthy.

  • Makes sense. Me & my wife caught it and had symptoms but were really only worried about my mother who’s elderly and lives with us. She’s type O. She never caught it and if she did, never showed symptoms or tested positive. I thought for sure she would catch it. Maybe we were just careful though.

  • You don’t “catch” Covid-19, you contract the SARS-CoV-2 virus which can lead to you developing Covid-19 – just like developing AIDS can only happen after you’ve contracted the Human Immunodeficiency Virus (HIV).

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