
Direct evidence for T-cell immunity as a factor behind Covid-19 heterogeneity - kaonwarb
https://science.sciencemag.org/content/early/2020/08/04/science.abd3871
======
trenchgun
Misleading headline. From the article:

> Based on these data, it is plausible to hypothesize that pre-existing cross-
> reactive HCoV CD4+ T cell memory in some donors could be a contributing
> factor to variations in COVID-19 patient disease outcomes, but this is at
> present highly speculative

Also I recommend to read this:
[https://www.theatlantic.com/health/archive/2020/08/covid-19-...](https://www.theatlantic.com/health/archive/2020/08/covid-19-immunity-
is-the-pandemics-central-mystery/614956/)

~~~
sradman
The section _Direct evidence of reactivity to HCoV epitopes homologous to
SARS-CoV-2 epitopes_ [1]:

> we designed a peptide pool encompassing peptides homologous to CD4-R30
> epitopes, derived from HCoV-229E, HCoV-NL63, HCoV-OC43, HCoV-HKU1 and
> several other HCoVs (see Methods), for a total of 129 HCoV homologs
> (HCoV-R129; table S2). Similarly, we synthesized a pool that encompassed
> peptides homologous to the SARS-CoV-2 CD4-S31 epitope pool, consisting of
> potential epitopes derived from other HCoVs, for a total of 124 HCoV
> homologs (HCoV-S124; table S3).

The "speculation" disclaimer, IMHO, is based on the assumption that the
designed peptide pools invoke responses similar to their viral homologs. I
have no issue with the "direct evidence" heading as this research makes an
important step in demonstrating cross-reactivity.

Teasing out the degree of protection this cross-reactivity provides in real-
world populations is a much harder problem.

[1]
[https://science.sciencemag.org/content/early/2020/08/04/scie...](https://science.sciencemag.org/content/early/2020/08/04/science.abd3871#sec-4)

------
nostromo
> We demonstrate a range of pre-existing memory CD4+ T cells that are cross-
> reactive with comparable affinity to SARS-CoV-2 and the common cold
> coronaviruses HCoV-OC43, HCoV-229E, HCoV-NL63, or HCoV-HKU1. Thus,
> variegated T cell memory to coronaviruses that cause the common cold may
> underlie at least some of the extensive heterogeneity observed in COVID-19
> disease.

Could we just start deliberately spreading these weaker cold viruses then?

~~~
vikramkr
Maybe, but thats basically developing a new vaccine, and in the time it takes
to test that out and make sure it's safe and effective, we'd already have
other vaccines on the market that might be more likely to be effective. Theres
also the risk of antibody dependent enhancement where a competing immune
effect makes the disease worse if previously infected with a different strain
as seen in the dengue family

~~~
djsumdog
It's silly to think we're going to have a safe vaccine on the market any time
soon. It'd probably be safer to give everyone coronavirus common cold viruses
if it can build an immunity.

..and Immune Enhancement Syndrome one of the serious consequences of the SARS1
and MERS vaccines that never made it past their trials.

There are a lot of factors to immunity beyond antibodies. Traditional vaccines
are either close viruses in the animal world (horsepox for smallpox) or heat
treated inactivated virus (flu). We know they produce anitbodies, but there
are hundreds of other parts of our immune system (complement system, inane,
etc.) that might interact and form memory as well.

Vaccines come out of bad places; from eras where hundreds if not thousands of
people were going blind, dying or getting paralyzed by disease. It was easier
to just test things on people back then too, and a lot of them died (Chinese
were inoculating people with actual smallpox 300 years before Jenner
discovered making a vaccine from Cowpox/horsepox).

In the 1970s, the Swing Flu vaccine was a disaster. Sure millions of people
got the vaccine and were fine, but 3,000 people developed Guillain-Barre
syndrome. Some still have trouble walking or smiling (see the 60 Minutes
documentary from that era)

Vaccines need a lot of testing. I do not understand why we're trusting the man
who gave us Windows 95 to lead the Gates/Gavi alliance responsible for giving
us a "safe" vaccine in less than a year. That's insane.

~~~
SpicyLemonZest
The problem is that, at least in some populations, these viruses are only
moderately less dangerous than COVID-19. There are recorded nursing home
outbreaks (e.g.
[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2095096/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2095096/))
where a common cold coronavirus killed 5-8% of residents.

~~~
partyboat1586
Without wanting to sound disrespectful to those affected 5-8% is pretty good
for a care home.

~~~
SpicyLemonZest
It is, unfortunately, but it's probably bad enough that it's not something a
government could deliberately do.

~~~
ithkuil
Would it make sense to skip those age groups? We still have social distancing
in place; if we try to protect those people from sars-cov-2 they will also be
protected by other milder variants we nurse in the wider population.

On a similar note: when a vaccine gets developed, does it make more sense to
vaccinate those age groups (on the grounds that it will protect the most
vulnerables) or to vaccinate everybody else (on the grounds that the vaccines
may not be 100% safe and thus it may be safer for those age groups to benefit
from the herd immunity)?

~~~
raxxorrax
You cannot deliberately infect people of any age group anyway. I would skip it
and doesn't sound more convincing than measles parties.

~~~
gridlockd
You mean you can't "ethically" infect people? I disagree, it just comes down
to risk. Many vaccines and medications have rare but potentially severe side-
effects, but we administer them anyway due to risk versus reward.

Let's say you have a 5% chance of dying from COVID-19, a 10% chance of
contracting it, but only a 0.05% chance of dying from some harmless
coronavirus that would reduce your chance of dying from COVID-19 by half. It
would be irrational _not_ to deliberately contract the harmless coronavirus.

The problem is just that we don't know all these variables, especially for a
given individual.

~~~
raxxorrax
A potential COVID vaccine is an example. I doubt you could ethically instruct
people to get a shot for such a health experiment. You can require them to get
one to use certain services, but bodily autonomy has precedence in my opinion.
That is even more relevant for living pathogens.

Being together with other humans is always a health risk if you want to look
at it like that. While it might be incredible stupid to not take the lesser
risk, you cannot force people to be rational.

------
phendrenad2
So basically this is saying that previous exposure to various versions of the
common cold can lead to some covid resistance?

~~~
danybittel
But why are the elderly more susceptible? Shouldn't the probability of
exposure by higher, the older you get? Wasn't that the reason the Spanish flu
killed more younger people?

~~~
nxpnsv
Are elderly more susceptible to infection or adverse outcome once infected? In
the latter case we still can see worse stats for the elderly.

------
LordHumungous
How can I get infected with one of those other Coronaviruses?

~~~
__blockcipher__
Exchange bodily fluids with as many young people as possible. AFAIK there’s no
way to be able to get voluntary exposure in a lab. Which is lame, imagine
getting a precise dose of cultured $HCOV.

OC43 has like a 9% nursing home fatality rate tho (which is kind of a hint
that SARS-2 isn’t too special as far as mortality is concerned)

Anyway if you have kids you have probably already been exposed to one of these
CoVs at some point. The TL;DR is the more you do real life stuff the more
likely you are to have exposure. Add it to the long list of externalities due
to lockdown. Natural spread of pathogens is a good thing and not to be feared.

------
avancemos
From the abstract: "We demonstrate a range of pre-existing memory CD4+ T cells
that are cross-reactive with comparable affinity to SARS-CoV-2 and the common
cold coronaviruses HCoV-OC43, HCoV-229E, HCoV-NL63, or HCoV-HKU1."

1\. Populations may naturally have a head start towards herd immunity from
COVID. 2\. Sweden could be really close in that regard; their current super
low daily mortality and declining cases may point towards herd immunity.

~~~
raverbashing
The usual way to assess herd immunity is by antibody testing

I don't think Sweden got to 10% infection in the pop. at the moment (avg. for
Spain is 5% and 15% on the heaviest hit cities)

~~~
anoncake
The very article contradicts you.

~~~
raverbashing
I see, yes, the t-cell assessments are new but while we don't have accurate
values for those countries we have to rely on the antibody testing.

(Not to mention this whole t-cell story is being used by negationists and
"skeptics" to deny the _actual_ mortality of the virus)

~~~
dariosalvi78
A Swedish study has found that for X people with confirmed infection that have
antibodies, another same amount have t-cells and no antibodies.

------
DangerousPie
What's up with the editorialised title, which clearly overstates the
conclusions of the paper?

------
peter_retief
Does this imply that the COVID-19 virus will morph into the common cold virus?

~~~
vibrio
No. Mo more than a tiger will morph into a house cat.

~~~
RalfWausE
Well, with a few hundred to thousand generations and a bit selective breeding
i see no real problems here... just ask Fido about his wolf-great-great-
great-(and so on)-grandfather ;-)

~~~
vibrio
Yes, many things are theoretically possible. In relative terms Coronavirus
isnt that mutagenic. Every year for many years millions of people get seasonal
coronaviruses there hasn’t been a “morph” (whatever that means). The SARS and
SARS/CoV-2 crossovers did come from somewhere and it was bats which are REALLY
good at being virus incubators. We are not. I guess in the environment we all
are now in I’d prefer a message not be spread of a seasonal cold turning into
a deadly respiratory disease based on such an apparently unlikely
hypothetical. Or Let’s worry about things like swine and avian flus, which are
orders of magnitude better at “morphing” yet much of the population still
refuses to vaccinate annually.

~~~
vibrio
Just realized I got the original morph direction wrong. Please pardon.

~~~
peter_retief
That is possible, also viruses can make bacteria deadly, check this
[https://www.sciencedaily.com/releases/2009/04/090417195827.h...](https://www.sciencedaily.com/releases/2009/04/090417195827.htm)

------
armada651
This would also explain why the anti-body tests have proved so unreliable. A
lot of people already have reactive anti-bodies without being exposed.

~~~
__blockcipher__
Reactive t cells, not antibodies.

------
known
I believe Antibody is better than Vaccine
[https://en.wikipedia.org/wiki/Antibody#/media/File:Antibody_...](https://en.wikipedia.org/wiki/Antibody#/media/File:Antibody_Opsonization.svg)

