There are unconfirmed rumors that recovery may not confer lasting immunity (this is a priori unlikely but would make the situation much worse)
There is more reason to think that this could be true in this case than there would be for most viruses. A subset of common colds are caused by very distantly related coronaviruses. I can dig up the paper if I need to, but I found an analysis of healthy volunteers challenged with cold-causing coronaviruses they had been exposed to before, and found that if exposure was more than one or two years ago it was able to cause disease in half the people exposed.
There is also a phenomenon active in some flaviviruses by which antibodies developed during exposure to a strain that is closely related but just different enough to the one you are being newly exposed to actually allows the new strain to gain access to your immune system cells by allowing them to bind to cells which consume antibody-tagged particles without completely disabling it before it is engulfed, and a related phenomenon in the same flaviviruses in which low antibody titres of exact-match antibodies cause the same effect. I have no idea if the unconfirmed rumors of reinfections are to be believed, but if they are I might wonder if one of these two effects is in play rather than the acquired immunity crashing in a month. A potentially more likely explanation to me is that you had someone with very severe disease recovering, and then they get a cold or flu on top of it and they keel over.
As for a ‘cure’, there is no SARS vaccine after a decade of people trying (albeit not very hard given its containment) in part because the vaccine candidates frequently crash in animal studies because they have frequently actually made the disease *worse* upon infection, triggering immune overreactions. (Maybe via one of the above mechanisms?) Antiviral drugs are where I would put money on actual new things, both the nucleoside analogs (remdesivir) that block the viral RNA polymerase and protease inhibitors (like those used against HIV) tweaked to fit better into this particular protease. Chloroquine is fascinating—the biochemistry of its antiviral mechanisms is very broadly applicable in a way that it is hard to evolve around and is likely going to have some effect, though calling it a cure is probably pushing it.
I just read a news story suggesting that some of the recovered patients are perhaps still contagious. Which perhaps raises the question of recurring symptoms. Wondering if you have seen that or have thoughts.
Believable, considering that people are often contagious for the flu up to three or four days after they recover and kids can be contagious for even longer after they recover from it.
Mortality rate estimation, at this stage, is very hard. The relevant problems:
Severe cases are more likely to be detected than minor cases (but we don’t know how much more likely)
Nearly all of the quantitative data comes from China, which is underreporting both cases and deaths in an unknown ratio
Cases which end in death resolve faster than cases which end in recovery
On top of which:
No one knows the morbidity rate at all
There are unconfirmed rumors that recovery may not confer lasting immunity (this is a priori unlikely but would make the situation much worse)
The prior is a sample from a distribution which contained SARS, MERS, and an large but unknown number of variations of common cold
The timeline for a cure could be anywhere from a month (chloroquine or remdesivir works) to never
The practical upshot of all of which is, the confidence intervals are all wide enough to drive a truck through.
There is more reason to think that this could be true in this case than there would be for most viruses. A subset of common colds are caused by very distantly related coronaviruses. I can dig up the paper if I need to, but I found an analysis of healthy volunteers challenged with cold-causing coronaviruses they had been exposed to before, and found that if exposure was more than one or two years ago it was able to cause disease in half the people exposed.
There is also a phenomenon active in some flaviviruses by which antibodies developed during exposure to a strain that is closely related but just different enough to the one you are being newly exposed to actually allows the new strain to gain access to your immune system cells by allowing them to bind to cells which consume antibody-tagged particles without completely disabling it before it is engulfed, and a related phenomenon in the same flaviviruses in which low antibody titres of exact-match antibodies cause the same effect. I have no idea if the unconfirmed rumors of reinfections are to be believed, but if they are I might wonder if one of these two effects is in play rather than the acquired immunity crashing in a month. A potentially more likely explanation to me is that you had someone with very severe disease recovering, and then they get a cold or flu on top of it and they keel over.
As for a ‘cure’, there is no SARS vaccine after a decade of people trying (albeit not very hard given its containment) in part because the vaccine candidates frequently crash in animal studies because they have frequently actually made the disease *worse* upon infection, triggering immune overreactions. (Maybe via one of the above mechanisms?) Antiviral drugs are where I would put money on actual new things, both the nucleoside analogs (remdesivir) that block the viral RNA polymerase and protease inhibitors (like those used against HIV) tweaked to fit better into this particular protease. Chloroquine is fascinating—the biochemistry of its antiviral mechanisms is very broadly applicable in a way that it is hard to evolve around and is likely going to have some effect, though calling it a cure is probably pushing it.
I just read a news story suggesting that some of the recovered patients are perhaps still contagious. Which perhaps raises the question of recurring symptoms. Wondering if you have seen that or have thoughts.
Believable, considering that people are often contagious for the flu up to three or four days after they recover and kids can be contagious for even longer after they recover from it.