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[flagged] Coronavirus protective immunity is short-lasting [pdf] (medrxiv.org)
38 points by metafunctor 18 days ago | hide | past | favorite | 22 comments

Notice that this is for common coronaviruses, and doesn't mention SARS or MERS much: IIRC, the former elicited an IgG response years after exposure in an experiment. As far as I can tell, this preprint does not cite that work.

Indeed -- studies of SARS have something different to say. Here's one study that shows duration of antibody response to SARS is at least 3 years [1]. Here's a study that shows T cell response for at least 6 years [2].

MERS had a much, much higher fatality rate (~35%) and infected a small handful of people (~2500) so it's harder to get meaningful data.

[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2851497/

[2] https://www.jimmunol.org/content/186/12/7264.short

And more:

>Two findings emerge: first, the T cells generated back then are still active 17 years on. And second, those old T cells offer protection against the new coronavirus. https://www.telegraph.co.uk/health-fitness/body/no-antibodie...

It might be worth pointing out that this study is about coronaviruses in general, not the coronavirus that causes COVID-19 (SARS-CoV-2).

Also worth noting that strain is not controlled for in this study. The study acknowledges at the end that reinfection may be by different strains. Under the same parameters as this study it could be said that flu infection doesn't confer immunity. But, it does, just there are a lot of distinct strains of flu.

This is for common coronavirus but something very important must be remembered: The reinfection is not the same.

The first time you face a new virus, you don't have antibodies. You also have no information to generate them. Generating this information takes a long time, which is dangerous.

If you reinfect again after 12 months, you don't have antibodies, but there are cells that contain the information to regenerate the antibodies much faster than the first time you faced the virus.

So reinfection is not as dangerous as the first time.

> The reinfection is not the same

As a parent of young kids who manages to catch the stomach flu at least once a year from them, this is something I've come to appreciate a ton.

The first time we caught it after neither me nor my wife having caught such a thing for over a decade, it knocked us out for two days. Just completely miserable.

Now, four years and half a dozen rounds later, it's still terrible, but only lasts twelve hours or so.

Gotta love the immune system.

Sometimes that can backfire, and infection can trigger a deleterious immune response, or a severe reaction upon reinfection.

We already knew this about the general family of coronaviruses, but MERS and SARS both generated longer immune responses.

I imagine we're starting to look at people who had severe cases in March, and survived to see if their immune responses are still holding up 3-4ish months after and will be doing so for the months to come.

T cells also play a big part in long term immunity.


Mild reinfection without symptoms (& in all likelihood, decreased shedding) is functionally nearly the same as actual "immunity".

In a dynamic long-term analysis, such mild reinfections might even be for-the-best: it refreshes your immune response, and those around you in a similar situation, as if the virus itself had been turned into a naturally-circulating seasonal "booster shot".

What if the other four known 'common cold' coronaviruses were all just as challenging as Covid-19 when they emerged... but nowadays, everyone gets them 1st when young – & their immune system most able to adapt – thus rendering them relatively mild, or even undetectable, on all subsequent re-exposures over an entire lifetime?

Is anyone else worried that there won't actually be a usable vaccine for C19? After all, we don't have a vaccine for any other coronavirus. What makes people think we'll have it for this one, let alone "within a year"?

We don't have a vaccine for any other coronavirus because it's not really worth it; most people with the common cold coronaviruses only have mild symptoms. A SARS 1.0 vaccine was in development at one point, but they stopped because the virus was eradicated.

> most people with the common cold coronaviruses only have mild symptoms

Pretty sure the same could be said of C19, depending on how you define "most". However, cursory googling shows that there are _1 billion_ cases of common cold in the US alone every year (lots of people have it more than once), so it'd still seem like it'd be worthwhile if it were doable. Common cold accounts for 40% of all time lost from jobs and 30% of lost school time.

Only a minority of colds are caused by Cornaviruses though. Something like 20%

That's still 200M in the US alone.

There are at least four coronaviruses that cause the common cold. And immunity lasts only 6-12 months. So, this would be 4-8 vaccinations per year, for life, to reduce colds by 20%.

I might do that myself, but I’m not sure it would sell well enough to fund the costs of developing the vaccine.

The common cold is caused by _many_ coronaviruses and many non-coronaviruses. At least 200 in total, I believe. You’d need to develop (and take) tens if not hundreds of vaccines to do anything useful. There has been some work on rhinovirus vaccines, but it’s pretty natural that COVID (and sars-1 and mers, for that matter) get higher priority.

Also worth noting that coronaviruses only cause a portion of common colds. So it would maybe be 4-8 vaccines a year to stop perhaps 20% of common colds.

I hate colds, so I might do that, but it would hardly be a best seller.

> most people with the common cold coronaviruses only have mild symptoms.

Couldn't the same be said for the common flu? Most people shrug off influenza, but they develop a new vaccine for that something like twice a year (the efficacy of which isn't great.. https://en.wikipedia.org/wiki/Influenza_vaccine#Effectivenes...)

The efficacy of the influenza vaccine has a lot to do with the influenza virus genome, which is fairly different than coronaviruses, and due to that mutates far quicker.

Yes but I think the flu shot speaks to the industry's willingness to devote a lot of resources over-and-over again to a vaccine for an illness that isn't serious for most people.

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