If coronavirus goes around again, that could raise the death rate
It would be pretty novel for the human immune system to clear out the disease on it's own, then a few days later forget how to do that, and become re-infected. SARS-COV-1 saw immunity conferred for 2-3 years. [1] I suspect something similar is likely here, probably for a shorter duration due to the more limited severity, but long enough to get us to a vaccine.
Generally for as long as you show antibody response you won't be re-infected because that's what antibodies do. The link I provided to the study I referenced was specifically for the purpose of, and I quote: "to assess SARS patients’ risk for future reinfection."
"To be clear, most experts do think an initial infection from the coronavirus, called SARS-CoV-2, will grant people immunity to the virus for some amount of time. That is generally the case with acute infections from other viruses, including other coronaviruses." [1]
If you think this time is different the burden of proof is on you to provide studies and not provide unsupported, unsubstantiated conjecture.
[1] https://www.statnews.com/2020/04/20/everything-we-know-about...
In science, it's incumbent on those making the claim to provide studies and proof. That means you...
And to say that this is unsupported, unsubstantiated is ridiculous, and you know it. It's straight from the WHO's mouth.
Nothing I said contradicts the WHO.
> Don't you think that if this was a foregone conclusion, we'd be able to demonstrate that?
I'm sorry, do we need to re-prove how the immune system works? Why re-demonstrate the utterly obvious?
> Isn't it odd, that with people having been infected and recovered months ago, that no one is saying how long the antibodies persist?
No, because it hasn't been long enough. I'm confident that research is under way.
But an immune response from an actual virus should last for at least a few years. There are situations where you can get reinfected later in life if you're not exposed or given booster shots (likes Shingles).
Is there evidences that our adaptive immune system only generates short lived antibodies, and for what families of viruses?
It's like saying "I find it very strange no scientists came out on record this week with a study showing water remains wet -- does it?! How can we tell if we don't check again."
Lack of proof of an affirmative is not proof of a negative, and especially not when plenty of other evidence points in the direction of the affirmative (again, not conclusively).
I agree. In fact, its highly unlikely, as with coronaviridae we've seen that the milder the disease the less likely you are to obtain long-term immunity. Even SARS, a much, much more serious disease, gives you 2-3 years as per my reference.
However, that's not what GP was arguing. GP argued broadly that "people who test for antibodies [may not be] immune to future infections." That's extremely unlikely. The question is how many people, and for how long, and then how do we utilize that information. Broadly speaking a positive test for antibodies means you're pretty likely immune at the time the test is taken. Of course the question is how that antibody response changes over time.
I was pretty clear about that: "Generally for as long as you show antibody response you won't be re-infected because that's what antibodies do."
The WHO is saying don't issue one-off certificates of immunity for life on the basis of testing positive for antibodies at one point in time before we know more. I agree.
I suspect a round of infection is likely to tide us over to a broad vaccination program, but we need a study.
[1] https://thegate.boardingarea.com/wp-content/uploads/2016/04/...
""There is currently no evidence that people who have recovered from COVID-19 and have antibodies are protected from a second infection.""
They were prompted to issue this because some people were touting this idea of immunity being granted perpetually and allowing people to safely return to work.
"Broadly speaking, a positive test for antibodies means you're pretty likely immune at the time the test is taken."
That's in complete contradiction to what the WHO is saying. Read carefully: There is no evidence.
You're using circular arguments to provide bad information. Something you've consistently been doing.
"...but we need a study."
Why? You've said it's unlikely to be different than other viruses. Of course we need a study, because we don't know.
There is currently no evidence of X does not mean X is not true. It just means there's no evidence of X being directly true yet. Nothing I said contradicts the WHO.
What I said was that we can reasonably infer from similar coronaviruses (including both more and less severe ones that are up to 90% genetically identical) that immunity is conferred. Also from other viruses. We shouldn't base our global health policy decisions on that until we have conclusive evidence but there's no reason for you to continue with the messaging when all evidence points to immunity being conferred for some duration of time.
Specifically what I said was that we do not have enough evidence to issue prophylaxis certificates, but that chances are good immunity is conferred based on studies of very similar diseases. I also stand by the fact it would be hugely surprising (totally novel) that any of those testing positive right now are actually re-infections due to the limited timescale involved.
Seeing smoke doesn't mean there's fire, but it means there's a pretty good chance of fire. Yeesh.
https://www.technologyreview.com/2020/04/27/1000569/how-long...
powerful argument there, not.
With SARS1 there was continuing damage post 6 months.
SARS-COV-1 had an IFR (not CFR) of 14-15%. Broken out, it's less than 1% for people younger than 25, 6% for those aged 25 to 44, 15% for those aged 45 to 64, and more than 50% for people 65 or older, officials said. [1]
On the other hand SARS-COV-2 has an IFR of somewhere in the lower quartile of the range 0.1% to 1%, trending to around 0.3%.
Not to mention, I argued that lung function would recover, to which you said "strong argument, not [the much worse disease saw lung function recover in 6 months]" which implies you were actually supporting my argument not refuting it.
The coronaviridae family is huge, and fatality varies from ~0% in the 15% of common colds they cause to 0.1-1% for COVID to 15% for SARS-COV-1 to 50% for MERS. I can't stress this enough. SARS-COV-1 and MERS are not SARS-COV-2, they are much worse diseases.
[1] https://www.cidrap.umn.edu/news-perspective/2003/05/estimate...