What Do New SARS-CoV-2 Mutations Mean?

Editor's note: Information on the COVID-19 crisis is constantly changing. For the latest numbers and updates, keep checking the CDC's website. For the most up-to-date information from Michigan Medicine, visit the hospital's Coronavirus (COVID-19) webpage.

News reports abound about the fact that SARS-CoV-2, the virus behind the coronavirus pandemic, is mutating. A new viral lineage currently circulating in the U.K and elsewhere, called B.1.1.7, has many concerned that this new version is behind skyrocketing transmission rates.

In a new summary in JAMA, Michigan Medicine's Adam Lauring, M.D., Ph.D., and Emma Hodcroft, Ph.D., of the University of Bern, Switzerland summarize what the new variants of SARS-CoV-2 might mean for spread, immunity and the vaccination effort.

First, they note, mutations are typical for viruses, including RNA viruses like coronaviruses. Those that allow the virus to spread more easily will increase through natural selection. But mutations can also happen by chance alone. One of the earliest identified mutations of the spike protein in SARS-CoV-2, called 614G, may have benefitted from a chance event and does appear to allow the virus to spread more efficiently in animal models.

The B.1.1.7 lineage that has appeared in the U.K. and the U.S. appears to have outcompeted other versions of the virus and is likely more transmissible, emphasizing the importance of maintaining the wearing of masks, social distancing and limiting gatherings.

Lauring also discusses the implications of these mutations in a recent JAMA podcast.

Paper cited: "Genetic variants of SARS-CoV-2 – What do they mean?" JAMA. DOI:10.1001/jama.2020.27124