Experience from the IAV field indicates that multiple serial exposures to variant IAV strains might imprint (focus) the immune response to a narrow array of well-conserved viral epitopes relative to emerging subsequent strains and this might eventually reduce vaccine effectiveness. Randomizing multiple cohorts over time to either serial or partial immunization might also yield important neutralization data, although powering such studies for efficacy would be challenging. Larger observational studies of cohorts receiving serial immunizations might therefore also prove useful.
This suggests that it may be a good idea to avoid getting a booster now (with the ancestral spike protein) and wait for an Omicron-specific booster instead. (Use other precautions to avoid infection in the meantime.)
Although we believe it is likely that the current vaccines will continue to protect against severe disease caused by omicron, the possible need for a booster shot targeting a vaccine-resistant variant could be a reason to hold off for now on a booster targeting the original variant. For one thing, if omicron proves resistant to vaccine-induced protection against serious disease, then a booster dose with the current vaccine may not help. It’s also possible that repeatedly “training” the immune system to fight the original variant could reduce the effectiveness of a variant-specific booster. This phenomenon, called “original antigenic sin,” has been observed with influenza and human papillomavirus vaccines. In other words, for those not in immediate need of a boost, there may be a significant advantage to waiting until a booster more closely aligned with circulating variants becomes available; boosting on the original antigen could be counterproductive.
I don’t understand why you think that follows from that passage. I interpret it to mean serial exposure to a series of variant-specific vaccines may reduce overall effectiveness. e.g. Imagining a hypothetical variant sequence of V → V’ → V″. I interpret this as saying if you vaccinate for each with a variant-specific vaccine the effectiveness of the V″ vaccine will be less effective than the original vaccine was for V. Therefore they theorize it may be advantageous to break the chain and e.g. give half the people the V’ vaccine when available while the other half skips V’ and is given V″ vaccine when available.
Their reasoning isn’t entirely clear to me since it’s not clear to me exactly how and by what mechanism(s) the vaccine effectiveness may degrade.
From your linked paper https://www.cell.com/trends/immunology/fulltext/S1471-4906(21)00177-0:
This suggests that it may be a good idea to avoid getting a booster now (with the ancestral spike protein) and wait for an Omicron-specific booster instead. (Use other precautions to avoid infection in the meantime.)
A trio of vaccine experts made the same point in https://www.washingtonpost.com/outlook/2021/11/29/booster-shots-universal-opinion/:
I don’t understand why you think that follows from that passage. I interpret it to mean serial exposure to a series of variant-specific vaccines may reduce overall effectiveness. e.g. Imagining a hypothetical variant sequence of V → V’ → V″. I interpret this as saying if you vaccinate for each with a variant-specific vaccine the effectiveness of the V″ vaccine will be less effective than the original vaccine was for V. Therefore they theorize it may be advantageous to break the chain and e.g. give half the people the V’ vaccine when available while the other half skips V’ and is given V″ vaccine when available.
Their reasoning isn’t entirely clear to me since it’s not clear to me exactly how and by what mechanism(s) the vaccine effectiveness may degrade.