Is there any explanation why Covid doesn't affect some people at all?

[ansible]

It seems to have no effect at all on some people while being utterly devastating on others, this seems to be the root cause of why so many people still don't take it seriously. How can a virus be so selective?

[Rollo]

2. Interesting question...

During my life, I've occasionally run into people who say they never get colds. Probably genetics, for some reason they do get colds but are "asymptomatic" carriers. Perhaps Covid-19 has similar demographics. Some people are just genetically resistant to a symptomatic infection.

This brings up an interesting tangent: if enough people are asymptomatic, the virus may actually be more difficult to contain, because its spread does not result in management measures that limit spread through the gen pop: masking, isolation, etc.

[leftstreet]

4. Good point

This brings up an interesting tangent: if enough people are asymptomatic, the virus may actually be more difficult to contain, because its spread does not result in management measures that limit spread through the gen pop: masking, isolation, etc.

I don't think I've seen anyone really address that. That makes the CDC's relaxing the mask mandate all the more troubling, since they knew asymptomatics could indeed carry and spread the virus.

[jimfields33]

7. I've heard blood type O has no way to get it.

I hear it from O blood type people so it’s definitely not science grounded. I’m A blood type so I just say that interesting. Probably BS I’m sure.

[vanlassie]

9. If only we had a way to check!

[eShirl]

14. I'm sure that's something that would have been noticed long before now.

[jimfields33]

16. Oh for sure.

I didn’t argue because the two who told me this were both vaccinated. I just said interesting and went to another subject.

[inthewind21]

55. Actually..

It was looked at in late 2020. There was an actual study on this very topic.

https://www.hematology.org/newsroom/press-releases/2020/possible-link-between-blood-type-and-covid-19

[JoanofArgh]

19. I have O and had it . Caused double pneumonia. I wasn't hospitalized or anything

but that type O don't get it is bunk.

[jimfields33]

20. Thanks. Glad to hear the real deal.

Hope you are better now.

[JoanofArgh]

21. I am. Thank you! Weirdest thing I've ever experienced. Didn't even feel that sick but

I don't want it anywhere near me again.

[jimfields33]

22. I understand that.

[viva la]

28. O is like 40% of the population.

If there's any immune effect, it must be minimal.

[LeftInTX]

41. Lots of Hispanics have had Covid and died. Overwhelming majority of Hispanics are type O

[inthewind21]

56. Hmmmm

A new version of the vague, no information "some people say" statement.

[Jim G.]

64. And Your Reply Is Typical Low Post Count Snark

Hmmmm....

[LanternWaste]

60. Fascinating

[JCMach1]

63. Pretty sure the blood type theory was debunked by a study

https://www.nature.com/articles/s41598-021-84810-9

No association between antibodies and both risk of infection or susceptibility to severe infection was found. The current study, along with the variation in blood group association results, indicates that blood group may not be an ideal biomarker to predict risk of COVID-19 infection.

[ananda]

32. We've known this to be the case since Covid started.

This is not news.

[Rollo]

47. From what I've read, it has to be blood type O- (O negative)...

For it to be most protective against Covid-19, it has to be type O-, and then the person with type O- is only slightly (like 12%) less likely to get infected. Plus, O- is a small fraction of those who have type O blood. Most Americans have O+, which apparently doesn't confer the slight protection that O- gives. RH- blood type also confers some slight resistance.

Here's a graphic of the relative frequency of these blood types in various American groups:



Note that of Hispanic Americans with O blood type, over 90% have the O+ type.

https://www.reuters.com/article/us-health-coronavirus-science/type-o-blood-linked-to-lower-covid-risk-taking-vitamin-d-unlikely-to-help-idUSKBN2872LH

[Rollo]

48. And the plot (clot?) thickens with regard to blood types and Covid...

From: https://www.webmd.com/lung/news/20210303/why-blood-type-may-matter-for-covid-infection

WEDNESDAY, March 3, 2021 (HealthDay News) -- A new study provides further evidence that people with certain blood types may be more likely to contract COVID-19. Specifically, it found that the new coronavirus (SARS-CoV-2) is particularly attracted to the blood group A antigen found on respiratory cells.

The researchers focused on a protein on the surface of the SARS-CoV-2 virus called the receptor binding domain (RBD), which is the part of the virus that attaches to the host cells. That makes it an important target for scientists trying to learn how the virus infects people.

In this laboratory study, the team assessed how the SARS-CoV-2 RBD interacted with respiratory and red blood cells in A, B and O blood types. The results showed that the SARS-CoV-2 RBD had a strong preference for binding to blood group A found on respiratory cells, but had no preference for blood group A red blood cells, or other blood groups found on respiratory or red cells.

The SARS-CoV-2 RBD's preference to recognize and attach to the blood type A antigen found in the lungs of people with blood type A may provide insight into the potential link between blood group A and COVID-19 infection, according to the authors of the study. It was published March 3 in the journal Blood Advances.

[smirkymonkey]

3. That's what is so infuriating.

A lot of these anti-vaxxers/anti-maskers have taken no precautions since this whole thing started and have had absolutely NOTHING bad happen to them. This in turn fuels their belief that it is a "hoax" or a "conspiracy" just to take away their "freedum"!

I really wish that more of them would become gravely ill with this virus just to show them that it's not a joke.

[Rhiannon12866]

5. Then they obviously aren't watching the news

What's happening in Florida and Texas scares the #%$! out of me. Especially now that the year-plus mask mandate has been rescinded here in New York - as of July, just in time for "tourist season." Entrances now say that masks are only required for the unvaccinated, but you can guess how that goes. Everything was shut down last year. This summer everything's open with a vengeance. I've driven through Lake George Village and the sidewalks are packed like every other summer, with rarely a mask in sight. And I've seen license plates from as far away as Florida, Georgia, South Carolina, Virginia, North Carolina, Alabama and Utah! And that's just when I had to stop for a light. The fall and winter don't look promising.

[smirkymonkey]

36. Unfortunately, many innocent people who have done everything they can to prevent

getting Covid suffer because of these people spreading it.

It is so unfair that many of them don't get sick themselves because it allows them to justify their behavior and continue on with it, ensuring that this whole thing is just going to drag on endlessly.

I am so tired of being in limbo, just because there are so many selfish idiots in this country who have make this a political issue because of their ego and stupidity. I have just really had it with this whole thing.

BTW, hope you are doing well and having a good summer!

[Rhiannon12866]

37. And because of the anti-vaxxers, even those who are vaccinated are now getting Covid

On Friday, I went to a family funeral, my Dad's cousin who just turned 88 - and she was fully vaccinated. Her sister called me with the news, she was a nurse and her family can't figure out how or where she got it.

So many unnecessary and preventable deaths, if only people would just get the vaccine - like we have gotten our entire lives to prevent polio, smallpox, etc. A few years back, I had a friend who returned to college and she had to get the MMR vaccine before she could attend classes. I gave her a ride - and nobody thought anything of it. *sigh*

And I'm hoping you're having a decent summer as well! I'm hanging in there, just holding my breath until "tourist season" here is over!

[smirkymonkey]

45. I am so sorry to hear about your Dad's cousin, Rhiannon.

That is so sad. Especially since she took such precautions to stay healthy.

These people just make me so angry, but I'm not going to go off on another rant about it. It's hopeless and it only infuriates me to think about it. I blame the republican party for this. They are about 98% responsible.

I am sorry you have to tolerate tourists from all over. Lake George is so lovely! I just love upstate NY. It's one of the most beautiful places I have ever been to in my life. I might be biased though.

Other than popping into my office occasionally, I haven't really been out much, and even then, only in the neighborhood. Our neighborhood is kind of a tourist destination, however this year it really hasn't been as crowded as usual, and I am wondering if it's because they know that Boston is serious about mask wearing in many places of businesses.

Anyway, looking forward to the cooler fall weather and hopefully and end to all of this madness soon!

[Rhiannon12866]

46. Thanks, so much. It was very sad.

My (Irish) grandfather was the eldest boy of 11 children and these are the children of his closest brother, so I know all of them fairly well. My Dad always participated in these family functions, and they have always come for us, so now it's my turn to show up. There was a family picnic summer before last and I went to that and to a ceremony for their Dad - my great uncle - who received the Silver Star for his service in WWI which I attended, too, so it's not all funerals. *sigh*

And I really don't understand the attraction of Lake George Village, it's just packed with tourists and how many tee shirts and pizzas can they use? When I was 6-9 we lived in Ticonderoga, on the north end of the lake, and that was really lovely. We lived on the side of a mountain and from my window I could see the boats that came up from Lake George Village turn around. If I wanted to visit Lake George, I'd choose the less crowded north end of the lake.

And I don't go out unless I have to, either. Since the pandemic, Wednesday is the day I run errands and just get everything over with at once. Since they rescinded the mask mandate here in New York (except for the unvaccinated), I see few masks - usually just me and a few employees. I don't think "the honor system" is working. So I'm dreading the fall when school starts and we'll see what the tourists left behind. One thing that impressed me was that even though the church where the funeral was held was full - every single person wore a mask. And that includes the boy who sat in front of me who couldn't have been older than five. I don't know about everyone there, but my grandfather's side of the family are all Democrats.

[FirefighterJo]

6. Natural selection

For every virus, there will be a small to large part of the population that was already 'programmed' with body defences because of their own mutations in their bloodline. Like viruses, we as humans qlso experience mutations in our DNA when life is created.

[meadowlander]

8. I saw an interesting theory about long haul covid

that it was reactivating the Epstein Barr virus in people that had previously had mono and that's why they had such severe long term symptoms.

https://www.webmd.com/lung/news/20210630/could-the-mono-virus-be-driving-long-haul-covid#1

I'm not an expert, but it would be interesting to see if Covid acts in combination with other more common diseases and they amplify each other somehow in certain people.

[Rollo]

49. Yes, while reading up on viruses in the past few weeks...

I learned that a number of viruses can go "dormant" inside our bodies, probably to evade the immune system defenses. Then like the Epstein-Barr case, they can "wake up" and reactivate or whatever, and cause new problems.

[ShazzieB]

62. UGGHHH.

I had mono in college.

I now have yet another reason to hope to hell I never get covid! (Like I needed another one! )

[Spider Jerusalem]

10. Secretor status may have something to do with it

non-secretors don't express blood group antigens in bodily fluids like saliva, mucus, etc and are evidently less likely to have severe illness or require hospitalisation if they get covid: https://pubmed.ncbi.nlm.nih.gov/34124710/

[multigraincracker]

11. It is like diarrhea..

it runs in your genes.

[eShirl]

15. ahhhh

[Carlitos Brigante]

35. .

[betsuni]

12. Like how some people can eat a large fast food meal and be fine, but

someone else will spend some quality time in the toilet.

[wnylib]

13. There was a study several months ago

that offered some insight into the genetics of vulnerability to covid. If I can find it online again I will be able to name the source of the study.

It focused on Neanderthal genes in modern humans. Subsaharan Africans do not have Neanderthal ancestry, but everyone else in the world does. There are two genetic mutations inherited from Neanderthals that play a role in covid. One is beneficial and helps modern immune systems resist it. The other is harmful and increases the chances of getting a serious case of covid.

If you inherit both mutations, the harmful one is dominant. The beneficial one might have a mitigating influence, though.

There are other factors, like environment, nutrition, availability of early health care if sick, preexisting conditions, and amount of viral load exposure that influence whether someone gets a serious case or not.

Another study indicated that people with type A positive blood seem to be more vulnerable. (That's my type.)

I will check for the source of that Neanderthal gene study.

EDIT: The study was done by two researchers at the Max Planck Institute for Evolutionary Anthropology. It was reported by several media, including MSN.com.

[bluedevil4]

17. Please do

I’ve discussed this with my doctor but my blood type is A/B. My daughter had Covid last summer and she was living with me along with her children. I got tested but didn’t get it. Then on thanksgiving an old HS friend dropped by, we hugged and talked. That Monday I found out she had Covid. I got tested again and didn’t have it.

I asked my doctor why (not that I was looking a gift horse in the mouth) no one new. I don’t feel lucky with this new variant and of course I’m vaccinated. I would be interested in what you said

[wnylib]

18. I just added an update edit to my post

on the source of the Neanderthal gene study.

Still don't know the source of the Type A study. It was posted here on DU in 2020. Will check that, too.

[JoanofArgh]

24. My mom had it before vaccines were available and tested negative twice.

She had an extremely mild case but you still could have had it and been asymptomatic.

[bluedevil4]

26. How did she

end up knowing? Curious

[JoanofArgh]

29. I caught it from her a week later and was a little sicker w/ same symptoms she had

(loss of smell and taste, no energy, fever for a couple days) and tested positive. My doctor told me she'd gotten a low dose of the virus. We're pretty sure she caught it from the guy who came to fix her cable . He was in the house for a short time. He was a young guy who was probably asymptomatic with a thin, loose -fitting bandanna around his face (worthless). I was around my mom for a longer period of time right after that and had a higher viral exposure.

Of course, it's certainly possible you didn't become infected. I remember when the pandemic first broke articles with emergency room doctors saying that every person in a family would get sick except one person and they were seeing a lot of this but couldn't figure out why.

[wnylib]

31. I've searched for the blood type info

but found mostly sites thst commented on it without stating the source of the study. Several conflicting reports.

I did find a Harvard study that was done in response to earlier reports. Apparently earlier reports claimed that type A positive people could get infected easier and type O were less likely.

But the Harvard study found that, when symptomatic people got tested, the ones with B and AB were more likely to be positive. O was less likely. However, they said that blood type was not an indicator of severity of infection with covid. Also, that anyone could get it regardless of blood type.

I have heard a claim that O is immune, but that can't be true. O is the most common blood type in the world. It is almost exclusively the only blood type among Native Americans, and they have been hit hard by covid.

In the end, I think other genetic factors are more significant than blood type, along with environmental factors, preexisting conditions, age, and amount of viral load in exposure.

[LeftInTX]

42. Yes, hubby is O positive. Mex-Am. Didn't have Covid, but Hispanics have been hit very hard

His DNA is 50% NA as is most Mexican-Americans...

I say Hispanics because they are a much larger group than Native-Americans (although they are generally about 50% NA) and more indicative that the O blood type thing is total, total, total, total BS...

The O blood type thing is probably something someone cooked up somewhere...and put it on one those lesser known "news sites" and it got picked up by the MSM...

I think I may have seen it first on a Chinese or Korean site or something like that....

[wnylib]

51. I have seen that blood type

distribution map before. It is part of a series that includes the distribution of each type.

Like other ethnic and racial groups, there has been intermarriage between Native Americans and other groups so that type O is not as exclusive as in the past, but still is very predominant among them.

[Mosby]

44. Differences by blood type have been ruled out.

https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2778155

[wnylib]

52. Since I have type A, it is good that the

blood type association has been challenged.

But the presence in modern humans of Neanderthal mutations that affect susceptibility to covid does seem to be substantiated by the Max Planck Institute. Two gene locations and their chromosomes have been identified. Prior to the covid pandemic, we already knew that Neanderthal genetic inheritence affects the modern human immunune system regarding a tendency toward allergies.

Those Neanderthal mutations are not the sole factors in getting infected with covid or how serious the infection is, but they do play a role along with other factors. That does help to explain the variations between asymptomatic people and those who get severe cases.

[treestar]

23. That is what makes it spread too

People who are sick stay home.

Similar to Typhoid Mary who never got sick but spread the disease.

[TreasonousBastard]

25. It's not the virus that's selective. We are born with an immune...

system that adapts as we age, so we will naturally have differing responses to disease.

[viva la]

27. There are usually a few people who are naturally immune

To any virus. Measles is terribly contagious, and pre-vaccine, when whole schools would come down with it, there was usually 2% or so who never got it.

Covid isn't that contagious, so likely more people have some level of resistance. Think of the spouses who are living with infected people. Some of them never getviym

Nothing to count on, of course.

[LeftInTX]

43. I thought that I never contracted German Measles, but titers indicated I was immune

I was one of the unlucky kids who didn't get to miss school because I didn't get rubella. My sister had it and my mom said, "Well, you might have it, but don't have symptoms, so you're going to school".

Years later, I had a titer done before I got pregnant. I had antibodies. I probably had it when my sister did and just didn't have symptoms...

[viva la]

54. Me too with rubella.

Exposed enough to have the antibodies, but never sick. I got a shot as an adult just in case.

[Act_of_Reparation]

30. Genetics.

It's likely due to mutations that prevent the virus from binding to host cells.

[Johonny]

40. Yes, even the plague and HIV don't infect everyone

some people have genetic mutations that create immunity. In the case of the plague and HIV I believe it's the same set of mutations.

I'm sure not enough time has past to identify all the key gene responsible for covid outcome all though there are some previous research in this area.

[Hugin]

33. The immune system is complex.

It can even vary in the same individual from day to day.

Why do some people have allergies and some don't?

[cinematicdiversions]

34. To a lesser extent the same thing happened with AIDS

There were people exposed hundreds of times that simply were immune.

They traced the genetics to black plague survivors in medieval Europe if I recall correctly.

[Rollo]

50. Yes, I saw an article recently (from 2005) that discussed the HIV resistance...

As I recall, it was in Viking populations in Scandinavia, who also traveled to other parts of northern Europe such as Russia. The presence of the HIV resistant gene in two copies required for full protection is very small, like 1% of the population, although I suppose it might be higher in some Nordic groups.

Here's one article, and it says the Black Death connection might not be valid, but rather some other malady might explain it (like smallpox or dysentery):

https://www.wired.com/2005/01/genetic-hiv-resistance-deciphered/

And then there's this one, which also mentions smallpox:

https://www.nature.com/scitable/blog/viruses101/hiv_resistant_mutation/

[Maru Kitteh]

38. For any infectious disease that exists there will be some who

never become symptomatic, no matter their exposure.

[Skittles]

39. correct

and look at how people can vastly respond to pharmaceuticals......people get hooked on Vicodin but when I took it one time after a dental procedure, I got so sick......never again

[WCIL]

53. I am one of the lucky ones (so far)

My 3 co-workers AND my husband were diagnosed with Covid at Halloween. I never got sick at all, and while I quarantined, I did not isolate from my husband as he really needed me. I had an antibody test in January and it appears I have never had it.

My blood type anecdata - my husband is B+, and he was very sick (but not in danger). My boss is O+ and had a little sore throat and lethargy, my other boss is B+ and didn't really feel badly at all, and my other co-worker is O- and only lost her taste and smell for a while.

I take it very seriously, and worry that the next round will get me.

[RobinA]

57. People In My Family

rarely get the flu and they never get flu shots. I know people who get flu shots every year who get the flu every year. My father, a physician, never had an upper respiratory infection in the 60 years I knew him. He got Lyme disease and never got one symptom except the bull's eye. He had freakin' TB and never had a symptom. I've had flu maybe three times, my sister never. So far, no COVID here. Genetics.

[LeftInTX]

58. I had the Hong Kong flu and I kinda wonder if it provided some long term immunity

Studies have shown that people who strong flu in the past have some immunity in the future....

I have only had one flu shot. I get lots of other stuff every year, but don't get the flu...

[ansible]

59. Could be possible, I haven't gotten covid yet got knocked out by the 2018 flu variant

61k people died then, I was infected too and couldn't even get out of bed for a week

https://en.wikipedia.org/wiki/2017%E2%80%932018_United_States_flu_season