People who have taken at least three doses of the original version of the COVID-19 mRNA vaccine have been strongly immune imprinted, a study by the University of Washington (UW) found.
Consequently, when vaccinated with the most recent COVID-19 XBB.1.5 mRNA boosters, recipients produced few to no antibodies specific to the XBB.1.5 variant.
Immune imprinting occurs when previous infections or vaccinations leave such a strong immune memory that the body continues to produce immune cells and antibodies targeting the previous immune experience—even when exposed to a new variant or vaccine.
“[Immune imprinting] could be a problem if the person was unable to mount a useful immune response against a new variant,” Dr. Stanley Perlman, an immunologist and microbiologist at the University of Iowa, told The Epoch Times. He was not involved in the study.
While that did not occur in this study, most of the antibodies made following vaccination targeted the original COVID-19 variant and not XBB.1.5.