> It depends entirely on an individual immune system detects and combats a particular infection.

How is that different from a vaccine?

The vaccine either contains or triggers the production of a specific protein that is (fairly) stable across variants - so there's only one thing for the immune system to key off. The concern around natural immunity is that your immune system may respond to some aspect of the virus that isn't as stable, ie it ends up recognising part of the virus that's present in your current infection but may not be in a later infection.

In reality it seems that the immune system does tend to end up targeting the same protein that's in the vaccine, but may be targeting different portions of it (https://pubmed.ncbi.nlm.nih.gov/34103407/ talks about this). My understanding is that current data suggests the naturally acquired immunity is about as robust as the vaccine acquired one, but this wasn't a given.

Thanks for the excellent reply. Sorry about the folks who are not equipped to understand it's relevance or contents.

I've got a PhD in genetics.

If you want to optimise for targeting a specific virus, then yes, narrowly targeting the most stable functional element of that virus is preferable to targeting other elements of that virus. If you want to optimise for having a broad response to related viruses, then a less narrowly targeted response is preferable.

I was explaining why there's potentially a difference between natural immunity and vaccine-mediated immunity, and why one of these may well be preferable if the goal is to generate maximum immunity to a widespread virus. But that's not the actual goal, and as a result policy decisions may differ. Is the risk associated with vaccinating people who have some degree of natural immunity justified by any improvement in immunity they gain as a result? I don't know! I have opinions on the matter, but I'm not qualified to make that determination.

is this going well for you

I didn't realize I was supposed to be playing for high score; I think I've dug into the truth a bit though.

stop embarrassing yourself.

Congratulations!

>Anecdotally, I know someone who has been infected twice

How does he know he was infected twice?

Saying that a PCR test returned positive values two times isn't a great answer - since by its nature PCR is only counting the existence (above the programmed threshold post amplification).

Serology is the only way to know for certain you were/are infected.

This highlights one of the bigger issues we have: PCR test are a very cheap and a useful way for getting estimates but their failure rate is high enough to make it pretty poor basis for doing large scale data analysis.

PCR. About 9 months apart.

Out of curiosity, couldn't this patient have experienced a case of long-haul covid?

I’ve had COVID twice - in December and then just a few weeks ago.

Long haul COVID doesn’t spring back to life and give you a fever for 12 days straight. I had essentially the same symptoms both times: fever, extreme fatigue, a dry cough, complete loss of taste of most things, etc.

Long story short, even if you didn’t get tested one of the two times (I tested positive both times) it’s pretty freaking obvious what you have as long as you don’t have a mild case. My wife got it this time around, and we got her an infusion of monoclonal antibodies early as she’s pregnant. She only had a fever one night, and in trying to explain how she felt I asked her “it feels like you just want to stop existing, right?” She agreed. Before that night it just seemed like a cold for her.

Thank you! I've been fortunate enough to not experience covid, though I've had quite a few family members with cases ranging from annoying and acute to quite devastating and chronic. I appreciate your input; though it's anecdotal, it does help give some greater sense for the individual experience of covid. Although let me not be crass: you have my greatest sympathies for your ill-experiences. I sincerely hope that you're well-recovered, and I wish the best for your loved ones.

Why is it "harder"? I assume you mean harder to quantify than vaccination immunity and I don't believe that's the case, but I'm curious why you believe that is the case.

edit: surprising downvotes so I probably didn't communicate my point well.

I can't imagine a reason why natural immunity would be harder to quantify than vaccine induced immunity. It would seem to me the methodology to quantify both would be very similar.

With a vaccine, you get a standardised dosis of an agent resembling the disease or just a part of it. The remaining variability is the response to that standardised input.

With an infection, you have no control over the degree of exposure, so on top of the variability of the response comes the variability of the exposure.

Additionally, in case of exposure of the full pathogen, there is some variability to what part of the pathogen the immune system will respond. That part can actually be a good thing in total.

Nobody knows what dose was delivered to the “natural immunity” group, how many times, or when.

there are very similar issues with the vaccine - the same dosage of the vaccine will not behave the same in everyone

but this is a good point I hadn't considered, thanks

Seems we should be able to test for antibodies though. Why aren't we?

we are testing for antibodies but antibodies aren't the only immune system response and depending on who you ask might not even be the "main" defense against covid.

It's a blood test, and I suspect that it's even harder to motivate everyone to get a blood draw than to get a vaccine.

>It depends entirely on an individual immune system detects and combats a particular infection.

Pardon my ignorance, but does this mean by contrast that vaccines are designed to induce a uniform response across immune systems?

EDIT: A reply (deleted before I could respond) mentioned that immune systems will combat the infection by some "pattern" of it's own design, but a vaccine will encourage the immune system to respond in a predetermined way, (increasing likelihood of uniformity, answering my question).

Is this accurate?

> Pardon my ignorance, but does this mean by contrast that vaccines are designed to induce a uniform response across immune systems?

Also not an expert and curious, would that not be a (the?) design goal of any vaccine?

there is no way for it to be perfectly uniform. Let's just say that the immune system employs several layers of RNG (random shuffling of DNA, and also it shoots mutations at certain segments of DNA) to evolve its responses.

A more uniform response than the pathogen itself? Yes. But I think the actual goal of modern vaccination is not a uniform response, but a directed response. Don't waste your time looking at these parts of the virus, spend it on this (important) part.