I’m very interested to hear what the serious scientists here think. I know @Mercer hasn’t been around in a while, but I would love to see his thoughts.
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Curtis, I share your curiosity on this topic. And I’ve wondered about the predictions that a great many young children will not be getting their measles and rubella vaccinations because of fears of visiting clinics during a pandemic. And because many families lost their health insurance when they lost their employment, many children will not get vaccinated for financial reasons. I don’t know if there are federal programs to make sure vaccinations proceed throughout this crisis.
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Considering that unvaccinated children pose a significant threat to pregnant women vulnerable to German measles—as well as those children being more vulnerable to COVID-19 if they lack routine vaccinations, it would seem that we need major government action now. A German measles outbreak several years from now due to this pandemic situation could have huge consequences in life-long disability for children yet unborn.
The similarity between those putatively homologous sections of the proteins in question do seem quite compelling.
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It’s an interesting hypothesis. Probably worth noting that the scarcity of cases among children may not need an external explanation. Some other viruses have a similar pattern. Most children do not have symptoms when infected with Epstein-Barr virus; it is mainly those who are infected as teens or older who have mononucleosis symptoms. The risk of severe chicken pox increases with age. Our immune systems react differently as we age. So it may be the case that something similar is going on with SARS-CoV-2, independent of vaccination. But that should also be considered a hypothesis at this point.
The MMR question can obviously be tested more directly. But it could also potentially have an impact on clinical trials of some SARS-CoV-2 vaccines. Some vaccine candidates use the attenuated measles vaccine strain as a vector to deliver just a portion of the spike protein of the coronavirus. If there are cross-reactive antibodies from the measles virus, those vaccine candidates may be more effective.
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@AllenWitmerMiller We don’t say German measles anymore, its rubella. 
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True, @patrick. I show my ol’ dinosaur colors yet again!
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Wow. The CDC webpage still includes “German Measles” on the title line for rubella. (And I hadn’t heard the “Three Day Measles” name before.)
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IIRC, the correlations have been independent of age.
Is there any evidence that (detectable) cross-reactivity is involved?
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Other vaccinations are correlated with reduced COVID-19 incidence, including BCG and Japanese encephalitis. I hope it’s true, as I just got the latter 18 months ago.
But since severe disease is fundamentally runaway inflammation, it may be that these other vaccinations may help young and healthy people, while exacerbating disease for at-risk people, as vaccinations induce inflammation too.
IOW, even after a perfectly controlled clinical trial that works beautifully in healthy volunteers, when given to the population at large, could make things much worse for some people.
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This particular paper was not about an observed correlation between vaccination and COVID-19 incidence. Rather, it is a largely hypothetical paper attempting to explain the observation that children are underrepresented among COVID-19 cases.
Not reported here. The paper does present some computational analysis indicating SARS-CoV-2 may have a similar 30 aa epitope to MMR vaccine strains.
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I think this result is extremely preliminary. It requires far more validation. Quite a few things correlate with youth vs aged, and MMR is just one of them.
The only meaningful evidence here is the sequence similarity of a putative epitope.
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Viral expression systems may also be needed to produce a properly glycosylated spike protein. I have a sneaking suspicion that glycosylation is going to be important in vaccine design.
https://science.sciencemag.org/content/early/2020/05/01/science.abb9983
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Perhaps, but interestingly enough, many of the new vaccines are genetic. They aren’t protein or viron vaccines. That should change your calculus substantially.
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After a little bit of digging around, the authors of the glycosylation paper above were able to get properly glycosylated spike protein using a standard mammalian expression system in human embryonic kidney cells (standard cell line for expression). In other words, the other parts of the SARS-Cov2 genome wasn’t needed for proper glycosylation. If the method of action for DNA/RNA vaccines is translation of the spike protein ORF then it may work. I would only worry about the level of translation which may be helped along by a strong viral promoter.
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A highly related question is whether or not the MMR epitope is glycosylated in a manner similar to the SARS-Cov-2 epitope…
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