Michael Farzan, an immunologist at the Scripps Research Institute, says that the fact that the N501Y mutation appears to have appeared independently several times in different geographical areas is further evidence that it does give the virus some sort of advantage. Other spike protein mutations, including one called D614G that has been seen in the U.S., allow the virus to replicate better in the upper respiratory tract of mice, rather than the lower tract. This arrangement could allow the virus to more easily spread through sneezing and coughing. The D614G variant has been circulating for some time, however, and it has not been shown to be more infectious in people or to create more serious symptoms.

The mutations may not help this version of the SARS-CoV-2 virus evade all of the cells and proteins that our immune systems use to neutralize it. Initial data from the lab of Vineet Menachery, a microbiologist at UTMB, suggest that the N501Y variant is just as susceptible to our defenses as the original virus. But these genetic alterations might spell bad news for monoclonal antibody treatments against the virus. A December 1 preprint study found that the mutations drove changes to a segment of virus that lies very close to the regions recognized by monoclonals made by the pharmaceutical companies Eli Lilly and Regeneron, making it more difficult for the antibodies to bind and neutralize the pathogen.