Why No One Is Sure If Delta Is Deadlier
The coronavirus is on a serious self-improvement kick. Since infiltrating the human population, SARS-CoV-2 has splintered into hundreds of lineages, with some seeding new, fast-spreading variants. A more infectious version first overtook the OG coronavirus last spring, before giving way to the ultra-transmissible Alpha (B.1.1.7) variant. Now Delta (B.1.617.2), potentially the most contagious contender to date, is poised to usurp the global throne.