A new variant named omicron (B.1.1.529) was reported by researchers in South Africa Nov. 24, 2021, and designated a "variant of concern" by the World Health Organization two days later. Omicron is very unusual in that it is by far the most heavily mutated variant yet of SARS-CoV-2, the virus that causes COVID-19.
The omicron variant has 50 mutations overall, with 32 mutations on the spike protein alone. The spike protein — which forms protruding knobs on the outside of the SARS-CoV-2 virus — helps the virus adhere to cells so that it can gain entry. It is also the protein that all three vaccines currently available in the U.S. use to induce protective antibodies. For comparison, the delta variant has nine mutations. The larger number of mutations in the omicron variant may mean that it could be more transmissible and/or better at evading immune protection — a prospect that is very concerning.
I am a virologist who studies emerging and zoonotic viruses to better understand how new epidemic or pandemic viruses emerge. My research group has been studying various aspects of the COVID-19 virus, including its spillover into animals.