Thus, a vaccine designed for a common ancestor could have a better chance of being effective for a larger proportion of circulating strains. Another team took this idea further by developing a center-of-tree reconstruction method to produce a sequence whose total evolutionary distance to contemporary strains is as small as possible.
A vaccine designed for a common ancestor could be more effective against a wider range of circulating strains. A different research group refined this concept by creating a technique to generate a sequence that is as close as possible to the ancestral form, minimizing evolutionary distance from modern strains.