Original Antigenic Sin
Original antigenic sin, also known as antigenic imprinting or the Hoskins effect, refers to the propensity of the body’s immune system to preferentially utilize immunological memory based on a previous infection when a second slightly different version of that foreign pathogen (e.g. a virus or bacterium) is encountered.
This leaves the immune system “trapped” by the first response it has made to each antigen, and unable to mount potentially more effective responses during subsequent infections. Antibodies or T-cells induced during infections with the first variant of the pathogen are subject to a form of original antigenic sin, termed repertoire freeze.
The imprint established by the original virus infection governs the antibody response thereafter.
On the Doctrine of Original Antigenic Sin
Thomas Francis, Jr.
Proceedings of the American Philosophical Society
Vol. 104, No. 6 (Dec. 15, 1960), pp. 572-578 (7 pages)
Published By: American Philosophical Society
A 2017 paper published in the Journal of Infectious Diseases cited studies in the United States and Canada that indicated “that prior influenza vaccination can, in certain situations, produce actual increased susceptibility to infection.”
OAS mentioned in mainstream media:
But the possibility does exist that an inadequately tested coronavirus vaccine could interact with a different strain still circulating in the population and hinder the body’s ability to make strong neutralizing antibodies. That could potentially leave people unprotected or even enhance disease…