And now my 84-YO, not very healthy Dad is positive and symptomatic. Argh!
Is this what viral spike proteins are doing? Mimicking human cells?
Just spitballing, because I truly do not know: I had though the spike proteins were something akin to grappling hooks – that they could latch on to many types and textures of cellular membranes.
They did, well except for the vaccine part; change that to natural immunity. But those are old viruses, well adapted to infecting humans. So they did their evolving to become adapted millennia ago.
The way I heard it explained is that our cells have “ports” that open when special proteins contacts those ports. This is to allow nutrients and such to enter our cells but block out other stuff. Stuff that is supposed to come in has the right spike protein to open the port and allow the cell to absorb whatever is attached to the spike. The COVID virus has a spike which happens to open the same port. It’s like having a lock that multiple different keys can unlock. So the cell opens up when the spike of the virus touches the port and the cell absorbs the virus. But my concern is that by creating vaccines to target the spike of the COVID virus, they may inadvertently cause our bodies to target the normal spike we have on our own cells since the spikes are similar. I’m not sure if that’s something that could happen or not.
Not all receptors function as ports to shuttle molecules in or out of cells. The natural ligand for ACE2 (angiotensin-converting enzyme 2) is a small peptide hormone known as angiotensin II. Angiotensin II has a very important role in blood flow and blood pressure by inducing vasoconstriction and, indirectly, water/salt retention. ACE2 counteracts its effects by enzymatically cleaving it into smaller peptides that promote vasodilation. This happens on the cell surface or freely in the bloodstream. As far as I know (not an expert), ACE2 never shuttles angiotensin II into the cell.
The cleavage domain of ACE2 also happens to be target for the receptor binding domain in the spike protein of SARS-CoV-2. ACE2 doesn’t facilitate entry of the virus into cells other than to act as an attachment site. Another cleavage protein on the cell surface cuts the spike protein exposing the part that undergoes a structural change that allows the virus to fuse to the membrane of the cell and dump its genome into the cell.
Here’s some videos showing the binding and membrane fusion process.
Here’s another video that has a brief description of the renin-angiotensin system and ACE2 receptors
Can you elaborate on this:
(Clipped from a different thread.)
I haven’t seen much on research into what makes this virus more or less damaging, and I’m curious.
Well, other diseases would have done this when they first infected humans. There are other factors that come into play, too, such as with SARS-CoV-1, which used to just be called SARS. That illness was more severe and more deadly, which is part of what led to it not becoming a global pandemic. If it doesn’t spread as well, then there are orders of magnitude fewer opportunities to mutate and compete to become a dominant strain.
Fourth shot today (2nd booster - eligible because I’m living in geezerville). Another Pfitzer? Can I ask [should I ask] for a different one if the shots become an annual thing?
I decided to try Moderna for my 4th. I did it by choosing a place that only administered Moderna, and getting an appointment there. The pharmacist asked me when I got there (and she looked at my previous record) if I knew they only had Moderna, and if I was okay with that. I said yes, and she jabbed me.
Dad and stepmother got Paxlovid, and said it was like a light switch–symptoms went away overnight. Good news.
Apparently there can be a rebound effect after Paxlovid for some patients. (Gift link)
…
Crumley, like other patients who have experienced relapses after taking Paxlovid, is puzzled — and concerned. On Twitter, physicians and patients alike are engaged in a real-time group brainstorm about what might be happening, with scant evidence to work with.…
Infectious-disease experts agree that this phenomenon of the virus rebounding after some patients take the drug appears to be real but rare. Exactly how often it occurs, why it happens and what — if anything — to do about it remain matters of debate.
…
I guess there’s no such thing as a free lunch.
A few weeks ago, there were several articles (Bloomberg, Washington Post, likely many other places) about how people who have NOT caught COVID are worth studying.
Most of them seem to be interested in people with a household member who has caught it, but still test negative, so that would let our household out of the discussion.
One of the articles says " The study, which examined 52 people who lived with someone who contracted the coronavirus, found that those who didn’t get infected had significantly higher levels of T cells from previous common cold coronavirus infections ."
And I’d read an article a month or so back that suggested that something like that was why younger kids generally didn’t get COVID, or had less-severe infections if they did catch it.
I’ve not had any known exposure, luckily - closest I came was a few weeks back, when briefly in the same room with a friend - both of us masked - whose HUSBAND tested positive a day or so later (friend tested negative at the same time, but positive a day or so after that, so it’s unlikely she was infected when she saw us).
I went Moderna for my fourth as well. 3xPfizer, 1x Moderna (booster dose). Just based on epidemiology-pundit chatter it seemed like a very mildly good idea to cover more bases, though I doubt the difference is profound. As my HMO and county health dept. were both putting up soft roadblocks (online software was trying schedule me for another Pfizer based on my previous shots), I just did it through CVS who don’t give a shit and let you schedule whatever.
Oh, wow, your healthcare system was way more proactive than mine. I made myself an appointment at Walgreens.
A friend’s six year old daughter was sick last weekend. She tested negative at home. I was surprised when she told me she paid $25 for a package of two tests. She’d never heard of the free tests she could request by mail! Meanwhile I have eight (?) more coming tomorrow.
When people get infected with Covid-19, their immune system creates antibodies that target the spike protein, along with other targets. We know this because immunologists look at the antibodies of infected patients to select targets for vaccines, and the spike protein antibodies are prevalent. If those spike protein antibodies targeted existing proteins in humans, then people infected with Covid-19 would also be in trouble. In fact, this is a possible cause of myocarditis (inflammation of the heart muscle) that is caused by Covid-19, and to a much lesser extent by vaccination. These auto-immune responses may also have a role to play in long Covid and other post-Covid issues, but there is a lot more research required.
So for those who thought that omicron is “like a cold” and nothing to worry about, here’s a depre ssing article:
https://www.google.com/amp/s/www.cbc.ca/amp/1.6471582
Basically, a 22 yr old woman in Halifax NS had omicron in January or February and it only lasted a few days, after which she went back to work and university, until recently when she started get severe long-covid symptoms. They’re bad enough that she’s in a wheelchair, which her roommate pushes around if she wants to go for a walk. She was about to start a graduate degree but she’s had to scrap that and move back in with her parents.
I also have a colleague who just mentioned in passing that she has noticeable memory issues post-covid. I assume that she had omicron (though I’ll have to confirm) as I don’t recall her being out of action.
Another Covid-19 profiteer bites the dust.
Southern California “freelance internist” Jennings Staley, who billed himself online as representing “the bright side of medicine” and claimed to have a miracle cure for Covid-19, has been sentenced on a charge of trying to smuggle hydroxychloroquine into the U.S. to use in his “treatment packs”.
You could obtain a “concierge medical experience” from this doc for just under 4 grand, a steal. He also tried to lure investors in a get-rich-quick scheme.
Looks like other spa clinics in the area will have to pick up the slack now.
Recently, I was at a pharmacy and saw a man and his preschool son. The father asked for a rapid test. The son, sounding alarmed, asked, “Rapid? What’s that?” in a tone which indicated he thought that “Covid” was bad enough, and now there was this new disease called “Rapid”.
Alameda County, California, where I live, just reinstated the mask mandate for indoor public spaces.