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Good reasons for caution
Two covid vaccines share a common thread that might account for blood clotting in rare cases.
Note: I am not a doctor and am not advising anyone on a particular course of action. This piece is intended to inform the general reader.
The common thread between the Oxford-AstraZeneca covid vaccine and a similar vaccine from Johnson and Johnson, is the way that instructions for making virus spike proteins are delivered to human cells. Both vaccines use an adenovirus to do the work. Adenoviruses cause common colds in humans and the viruses used for the vaccine have been weakened and deliver Covid instructions almost exclusively.
The blood clotting problem reported to be associated with these vaccines is very rare, only a few for J&J and a couple hundred for AstraZeneca which has been distributed more widely. But it appears the problems may be related. It remains to be proven but the attendant low platelet counts associated with these clots in some people suggests that in addition to making antibodies to the virus proteins, the vaccines can, in some people, also stimulate antibodies to platelets. More specifically, it suggests that the platelet antibodies may be intended for the adenovirus which amounts to a cross reaction.
Antibodies work by attaching to their targets and forming small clumps containing virus particles held…
