The omicron subvariant dominating U.S. COVID-19 cases is more vaccine-resistant

A syringe is prepared with the Pfizer COVID-19 vaccine at a vaccination clinic at the Keystone First Wellness Center in Chester, Pa., Dec. 15, 2021. (Matt Rourke/AP)

The BA.5 omicron subvariant, which is now the most prevalent coronavirus strain in the United States, is four times more resistant to COVID-19 vaccines, according to a new study.

The strain, which is considered "hypercontagious," according to the Mayo Clinic, is more defiant against messenger RNA vaccines, which include Pfizer and Moderna.