What is Immune Imprinting
1. Immune imprinting is a phenomenon whereby initial exposure to one virus strain limits the development of immunity against new minor variant strains of the virus.
2. Researchers are largely in agreement if boosters are given in a very short period of time after the initial primary series, without allowing a resting period, there’s probably little benefit in having a booster shot for people who are not immunocompromised.
3. Repeatedly updating SARS-CoV-2 vaccines may not be fully effective because of limitations imposed by prior immune imprinting to ancestral SARS-CoV-2 strains.
4. SARs-CoV-2 is a new virus and few humans have yet been exposed to more than one SARs-CoV-2 or vaccine strain. It is possible that serial exposure to several related strains over time might be required to most effectively “imprint” memory B cell immune responses to ancestral SARS-CoV-2 strains and, consequently, limit neutralizing antibody responses to new strains.
5. Imprinting may come directly from an acute infection or indirectly through vaccination. It can result in reduced — or enhanced — responses to future variants with unknown clinical consequences. The former is beneficial, but the latter is not.
6. It is hoped that immune imprinting will not be a major problem for SARS-CoV-2 infections, but the possibility that immune imprinting can substantially reduce the efficacy of future SARS-CoV-2 vaccines requires further research at this time.