As vaccine rollouts ramp up—or in some cases, stumble ahead—in countries across the world, the SARS-CoV-2 strain has rolled out some new features of its own, primarily in the form of rapid genetic mutations. Some evidence indicates variants of recent months have made the virus more infectious, or in one case, possibly more deadly.
Virus variants are inevitable and often benign. The new coronavirus has likely mutated countless times without attracting the attention of epidemiologists. But new strains identified in the U.K., South Africa, Brazil, and California have given some infectious disease experts pause.
Several studies indicate that the strain known as the B117 variant, prevalent in the U.K., may be as much as 70 percent more transmissible than the original virus. Two analyses in California suggested that a new strain on the West Coast, called B.1.426, made up a quarter of the infections they examined. As the news whipsaws between infection spikes and inoculation efforts, it can seem like the world has entered a race between variant and vaccine.