A more contagious strain of the coronavirus disease 2019 (Covid19) could become the “predominant” one in the United States by March, potentially making it even harder to get the pandemic under control, researchers from the Centers for Disease Control and Prevention predicted on Saturday.

The B.1.1.7 variant is believed to have first emerged in the United Kingdom in September, although it wasn’t identified until last month.

It has been detected in more than 30 countries, with 76 cases across 10 US states, the CDC researchers said.

The variant’s rapid spread could slow population immunity spurred by the Covid-19 vaccines, two of which, from Pfizer-BioNTech and Moderna, were approved for use in the United States last month, they said.

“Increased … transmission might threaten strained healthcare resources, require extended and more rigorous implementation of public health strategies and increase the percentage of population immunity required for pandemic control,” the researchers wrote.

“Taking measures to reduce transmission now can lessen the potential impact of B.1.1.7 and allow critical time to increase vaccination coverage,” they said.

The researchers called for enhanced efforts to identify those infected with the new strain, through increased testing capacity and contact tracing initiatives.

Contact tracing is a public health strategy designed to track down people who may have been exposed to an infected person.

The predictions for future spread of the B.1.1.7 strain in the US are based on computer modeling, the CDC researchers said.

That modeling takes into account how other strains of the virus have already spread across the country, as well as the number of current cases and potential transmission, they said.

Given that the new strain spreads much more rapidly than other versions of COVID-19, more and more cases are likely to emerge, particularly if mitigation strategies such as mask-wearing and social distancing are not effectively implemented, according to the researchers. CURRENTPH