What’s the source on reinfection? That sounds kind of extraordinary.

It seems weird to think the body can clear an infection but have no ability to fight it later.

There is none, it is just speculation/hysteria like so much else about this virus.

There's been only a very few cases globally where a person who previously tested negative later tested positive, for which a test giving a false negative is a much more likely explanation - especially as these cases were early on when tests were more unreliable. Otherwise - everybody else who tests negative does so consistently.

The virus is very similar to the original SARS (genome about 80% the same which is huge). It is a relatively stable by virus standards not mutating massively. In fact, if you had SARS your are likely immune from covid19: https://marlin-prod.literatumonline.com/pb-assets/journals/r...

So the general scientific consensus I have seen is that there's no evidence to suggest covid19 is some sort of supervirus that will reinfect people and defeat your immune system.

There's also been some animal testing on reinfection : https://www.biorxiv.org/content/10.1101/2020.03.13.990226v1

Yes, reinfection is speculation and limits the virus to infect the population is speculation. Beyond the situation of the virus growing exponentially, there are few certainties.

I add this point because most of speculative arguments are used to claim allowing the virus infect a large portion of population won't cause much harm.

> Note that Italy, which has seen a high death rate, hasn't a strong drop-off at all, just gradual plateauing.

Regional differences? Lombardy's death rate is less than half of peak

I think that number should be 0.2% (2 / 1000) and not 0.002% (2 / 100000).

Yeah, 2% is the standard and more plausible in many ways than 0.002% [edit, WRONG ,missed a decimal point, should be 2% & .2%]. My comments above are about what this study implies, this something new.

Italy has had 24114 deaths. If take those as being in Northern Italy with a 27,000,000 population, that's 0.8931 % of the entire population. Even adjusting for age, that can't squared with 0.002% death rate [wrong wrong, it's 0.08931%, which is possible but with a huge infection rate, which maybe].

I think you've misunderstood the comment by zucker52: your post is using 0.002 and 0.002% interchangably. It's quite hard to figure out what you mean when the numbers are off by two factors of magnitude in places.

For example:

> So a 0.002% "fatality rate" relative to total exposures,

You appear to be deriving this from the computation 601/221000. That gives .27%, not 0.002%.

> Italy has had 24114 deaths. If take those as being in Northern Italy with a 27,000,000 population, that's 0.8931% of the entire population

No it's not. 1% of 27M is 270k, not 27k.

Damn, I am being sloppy,

Yeah, 0.08931% of the population of Italy experienced fatality.

If we assume .2% fatality rate, that implies 50% of the population was infected (which might make sense with an extremely contagious virus but that's more than even the cruise ships).

The issue is you're not adjusting for the exponential fatality risk for old folks, and that those in Lombardy are the oldest in Europe. It's hundreds of times worse for old folks than for young folks.

The US doesn't have a hundred times less old people than Italy. The whole "don't worry about old people dying" attitude of those eager to "reopen the economy" is kind of despicable.

Florida has 20% of it's population over 65 and it's 21 million people might similarly be rather hard hit.

> The US doesn't have a hundred times less old people than Italy. The whole "don't worry about old people dying" attitude of those eager to "reopen the economy" is kind of despicable.

It's totally despicable, and it's not my position.

I propose we do what the UK proposed, and what Sweden is doing: keep all vulnerable folks inside, provide them with services such as groceries and any healthcare they may need on-site, and release the low risk to build a protective barrier of herd immunity around them. That should have been evident when I said "old people were hundreds of times worse off."

That's totally orthogonal to my point, which is that you can't project the mortality rate of a population that's overwhelmingly disproportionately affected, scale it linearly onto the world population and assume that'll be at all representative of the reality on the ground.

And yes, Florida may be affected very badly, and the plan may need to be adjusted accordingly.

"Now, the other bad* scenario is the possibility that a lot "of sickness and death NOW is being driven by reinfection, that exposure isn't giving much immunity at all and instead of the unexposed dying"

This would explain: NYC vs LA vs Italy. Why isn't this theory brought up more?

"Wang, whose full name has not been disclosed for privacy reasons, is one of more than 100 reported cases of Chinese patients who have been released from hospitals as survivors of the new coronavirus — only to test positive for it a second time in the bewildering math of this mysterious illness."

https://www.latimes.com/world-nation/story/2020-03-13/china-...

> Why isn't this theory brought up more?

Because if reinfection so close to recovery were possible, it would make this virus really unique, and it doesn't really fit the available data very well. It makes much more sense that the virus takes a long time to clear after symptoms abate, and the tests have a really lousy false negative rate.

The common cold is infamous for mutating at a rate where you can catch the virus again two months after infection. And moreover, the common cold is also a coronavirus.

Moreover, if a lot of Covid infections are in the area and the virus is mutating quickly, a person might be exposed to a different strain soon after recovery and wind up infected, if the SAR-COV-19 is similar to the common cold. This would be hard to notice, since it would tend to happen as the virus was spreading rapidly anyway. It would become a problem only if people expected the virus to abate once everyone had been exposed.

See: https://www.technologynetworks.com/immunology/news/why-dont-...

No. The "common cold" is a collection of 200-something distinct viruses with the same/similar symptoms, only like 10-20% of which are coronaviruses. Most of them are rhinoviruses.

If what you were saying were true then we would be seeing a huge number of symptomatic re-infections and deaths in China and Italy. As far as I know the ‘reinfections’ have been asymptomatic. That suggests that the virus takes a long time to clear, not that it’s mutating.

There’s no evidence yet that COVID is mutating in a way that would cause reinfection. There haven’t been any documented confirmed cases, the speculative cases are much more likely false negative test results followed by actual positive test results.

The main reason should be that speculating on both this and the exposed-and-maybe-immune isn't that relevant for the more responsible approaches to managing the situation - isolation, quarantine, safety equipment, testing and contact tracing.

This kind of speculation is relevant to the more irresponsible approaches; "developing herd immunity" and "immunity certificates" but it mostly should be a reminder to "don't do that because you really don't know what you're getting into".

It’s not clear this is the responsible solution as there’s no evidence the entire process wouldn’t start again the minute restrictions are lifted due to the sheer infectiousness of the disease and the large number of people with no symptoms or limited symptoms.