Scientists studying flu vaccines have identified ways to overcome an obstacle called "original antigenic sin," which can impair immune responses to new flu strains.
Original antigenic sin (OAS) is a situation where the immune system is fighting with obsolete weapons and has trouble adapting. After encountering one viral strain, and then a new one that is related to the first, the immune system can respond by making antibodies against the first strain, resulting in a less effective defense.
Researchers at Emory Vaccine Center have demonstrated in experiments with mice that OAS can be overcome by using a vaccine additive called an adjuvant, or by repeated immunization with the second viral strain. The results were published this week in Proceedings of the National Academy of Sciences (PNAS).