So there’s no misunderstanding, I would drive three hours to get either shot. But there is a strong argument for a half dose.

(Reuters) Mexican doctor hospitalized after receiving COVID-19 vaccine is concerning. Quoting,

“The initial diagnosis is encephalomyelitis,” the Health Ministry said in a statement released on Friday night. Encephalomyelitis is an inflammation of the brain and spinal cord.

Encephalomyelitis does not result from atopy. It is a result of a cell-mediated autoimmune reaction. In the few 3rd World countries that still use the Semple rabies vaccine, it is a regular and frequently lethal side effect. Brain damage is frequent in survivors.

The Semple vaccine is made of animal nerve tissue with no purification. When encephalomyelitis results from this vaccine, it is the result of introducing into the body proteins which are both similar and different. The foreignness of the protein induces an immune response that also attacks native proteins. But this mechanism gives no hint as to why it would occur with an RNA vaccine.

A clue is offered by (Nature, 12/20/2020) The S1 protein of SARS-CoV-2 crosses the blood–brain barrier in mice. For a neat summary, see (ScienceDaily) COVID-19 virus enters the brain, research strongly suggests.

The Mexican physician has a history of severe allergic reactions. How could this tie in with encephalomyelitis? A possible mechanism:

• The patient had a “standard” anaphylactic reaction, which involves a huge histamine release.
• The Pfizer and Moderna vaccines cause cells at the injection site to produce a flood of spike protein, which, unbound to an adjuvant, is highly mobile.
• Since it is now known that the brain contains mast cells, the blood-brain barrier suddenly became porous. Even with prompt treatment, a substantial quantity of spike protein passed the barrier.
• With no previous exposure to spike protein, the nature of the immune response within the brain is a mystery. Encephalomyelitis could be the visible result of a massively apoptotic event.
• Had the patient  received epinephrine prophylaxis with the vaccine, this might have been avoided. Something to consider?

In traditional vaccines, adjuvants have been combined with antigen to increase the potency of the shot. Various theories explain why adjuvants work:

• The immune system requires insult to react. As a minor irritant, an adjuvant causes the immune system to respond more strongly to the antigen.
• When an antigen is attached to a poorly soluble adjuvant, such as alum, the half life of the antigen in circulation is greatly increased. This also reduces the mobility of the antigen.

As potentially toxic substances, adjuvants went out of fashion for a while, with preference for highly potent antigens synthesized by recombinant techniques. Now adjuvants are back in favor in new flavors.

RNA vaccines produce a sudden flood of unbound s-protein antigen. More traditional vaccines present antigens bound to larger structures, either adjuvants, or virus-like-particles. This reduces the mobility of the antigen, in this case s-protein, lessening the chance it can pass the blood-brain barrier. This “safety feature” cannot be incorporated into RNA vaccines.

Since this is unlikely to have a large lay readership, we could finish with Paracelsus. You know what he said. Even a handful of cases of encephalomyelitis could frustrate mass immunization.

So cut the dose in half. Yes, I’m still driving three hours for the shot. I’ll take mine with a side of epinephrine.