As the COVID-19 pandemic nears its one-year mark, the coronavirus variant first detected in the United Kingdom has been rapidly spreading throughout the U.S., a recent study found.

Termed the B.1.1.7 variant, the mutated strain has gained a firm foothold across the Atlantic, doubling in the U.S. every 9.8 days, according to the study, which has not yet been peer-reviewed and was published Sunday on the preprint server medRxiv. The study found that the variant is projected to become the dominant strain in the U.S. by March.

Other strains originating in South Africa and Brazil are also causing concern among epidemiologists.

“We’re in kind of a race between the speed at which the mutations emerge and the speed at which we can vaccinate people,” said Lee Riley, division head of infectious diseases and vaccinology at the campus School of Public Health.

The U.K. variant is more transmissible than the original COVID-19 strain, the study found, and may also cause more severe illness and higher mortality rates, according to Riley. He added, however, that each new strain has exhibited especially high transmission rates upon emergence, so it remains unclear whether the current trend will continue.

A mutation originally observed in the South African strain, which is also present in the U.S., has recently been found in the U.K. strain as well, according to Riley. This mutation decreases the neutralizing effect of antibodies, thus reducing the effectiveness of the COVID-19 vaccine.

Tests conducted in South Africa where the former variant was circulating widely, for example, found that three of the released vaccines had significantly lower efficacy rates than average, Riley added.

The variant that first emerged in Brazil, of which a few cases have been found in the U.S., is also “worrisome” due to its pattern of reinfecting populations already infected by COVID-19, Riley said.

“It is likely that we will continue to observe new variants of CoV-2 emerging as the pandemic progresses,” said Britt Glaunsinger, campus professor of plant and microbial biology, in an email. “Certainly not all individual mutations or variants are bad news for us. But some do have an impact and thus any new variants must be analyzed to evaluate whether they spread more rapidly, cause more severe disease or impact the effectiveness of the existing vaccines.”

Both Riley and Glaunsinger discussed the vital role of increased vaccination in curbing the effects of such mutations. Widespread testing and sequencing of the virus will also be crucial in detecting new variants, Glaunsinger added.

Detecting these variants is especially important as many current strains exhibit particular mutations that could hinder the effect of immunization, Riley added. He also stressed the importance of adhering to existing public safety measures.

“We’re all experiencing pandemic fatigue, but now is not the time to let our guard down,” Glaunsinger said in the email. “Mask up!”