Thanks for reading my work and for the question.
Vaccine Associated Enhanced Disease (VAED) can be caused by three factors:
1. Antibody-dependent enhancement (ADE) (enhanced viral entry in which the virus uses pre-existing antibodies — that aren’t neutralizing against the virus — to bind to the cells and infect them).
2. Production of faulty antibodies (from the vaccines) that bind poorly (or not at all) to the virus.
3. Hypersensitivity (allergic reactions to certain components in the vaccines).
In the case of atypical measles, the vaccines failed to produce adequate antibodies against the viruses. Whereas in the case of RSV, the vaccines induced hypersensitivity (believed to be from formalin) and production of faulty antibodies in the vaccinees, hence resulting in VAED.
However, in this case, there are autoantibodies generated against the IFN proteins, which are self-antigens and not against the coronavirus. Hence, based on my understandings, it isn’t quite similar to VAED. And because the autoantibodies were already detected in the blood samples of individuals before the pandemic, it shouldn’t have been caused by the vaccines as Covid-19 vaccines weren’t available at that time.
As to whether it may have been caused by previous exposure to known coronaviruses, I believe that it is unlikely. Currently, there are 7 known disease-causing coronaviruses: four that cause common colds (which we are often exposed to) and three virulent ones that have caused the SARS, MERS, and Covid-19 outbreaks. Based on the study, out of 34,159 blood samples from healthy individuals, ~5% of them have these autoantibodies. These blood samples were taken from the general population in French, and the number of SARS and MERS cases in French during the outbreaks were only 2 and 7, respectively. So it shouldn’t have been caused by exposure to SARS and MERS coronaviruses. And if it were triggered by the four viruses that cause common colds, we might probably see a higher percentage of people with these autoantibodies. For these reasons, I think it is unlikely to be caused by previous exposure to known coronaviruses.
