A special case of COVID-19 with long duration of viral shedding for 49 days

[intrepidity]

https://www.medrxiv.org/content/10.1101/2020.03.22.20040071v1

Prolonged viral shedding is associated with severe status and poor prognosis of COVID-19 patients. Unexpectedly, here we report a non-severe patient with the longest duration of viral shedding. According to the investigation on the clinical and epidemiological information of this case, we concluded that this type of virus might have a low toxicity and transmissibility, but have a prolonged infective ability and was hardly to be eliminated in the body with regular therapy. However, infusion of plasma from recovered patients showed high efficiency in elimination of this virus. Our findings might shed light on the management of COVID-19.

[NNadir]

1. If true and confirmed, the existence of two subtypes is very good news.

The less severe sub-type may confer immunity, rather like Jenner's famous cowpox/smallpox finding, the first case of vaccination.

[denbot]

2. Could that also imply a high rate of mutability?

That strikes me as worrisome.

[NNadir]

3. RNA viruses are, in fact, highly mutable. This accounts...

...for the evolution of Covid-19, probably from Pangolin corona viruses. It is probable that these viruses have been around for centuries and never caused a problem greater than a common cold, if that.

It appears that the Covid-19 virus has a codon which translates in its ACE2 binding protein to a positively charged amino acid sequence of PRRA, proline-arginine-arginine-alanine. It is apparently, if I understand this correctly and believe everything I've read, the reason that the spike protein binds strongly to human ACE2. It is likely that any further mutation in this particular sequence will be less able to bind to ACE2. However the protein coat of a new mutant will still generate a immune response, which is how vaccines work.

We should expect that the majority of mutants will either non-functional (at least in humans) or weaker, less pathogenic, than the virus of immediate concern that possesses this particular peptide sequence on its spike-2 protein.

[denbot]

6. OK, this sounds less scary.

Thank you for that excellent explanation. I could follow your line of reasoning despite my having taken only lower division biology.

[Rstrstx]

5. There are many strains

This came from one of the most thorough websites I've seen about the virus:

https://emcrit.org/ibcc/covid19/

[customerserviceguy]

4. I've long suspected

that the fourteen day period might just be too short. A lot of the early assumptions have been based on observations of previous viruses of this type, and that might not be accurate in the case of this one.