AdvertisementWhy The Delta Variant Is Hyper-Contagious: A New Study Sheds LightUpdated July 21, 2021Michaeleen DouclefffacebookEmailThe numerals in this illustration show the main mutation sites of the delta variant of the coronavirus, which is likely the most contagious version. Here, the virus's spike protein (red) binds to a receptor on a human cell (blue). (Science Source)This article was originally published on July 08, 2021.