New coronavirus variant could become dominant strain in March, CDC warns

A new, more transmissible variant of the virus that causes Covid-19 could sweep the United States in coming weeks and become the dominant strain as soon as March, leading to a new surge of cases through the spring, the Centers for Disease Control and Prevention warned Friday.

The CDC believes the variant, known as B117, is still circulating at low levels in the U.S. Only 76 infections caused by the new variant have been detected, in 12 states, though testing for it has not been routinely conducted. CDC officials acknowledge the variant is likely more widespread here than is currently recognized.

Modeling work done by CDC scientists suggests that unless the pace of vaccination of the population increases dramatically and people adhere stringently to Covid-19 control measures, the new variant will spread rapidly. The work was reported Friday in the CDC’s online journal Morbidity and Mortality Weekly Report.

“We’re concerned,” Jay Butler, CDC’s deputy director for infectious diseases, told STAT. “We want to sound the alarm and urge people to continue to do the things that we know work.”

The B117 variant, first reported in the United Kingdom, transmits more easily from person to person; it is thought that people infected with it develop higher levels of virus in their upper respiratory tracts. Some studies suggest the variant is about 50% more transmissible than existing iterations of the SARS-CoV-2 virus.

To date, there isn’t evidence to show the variant triggers more severe disease, but that’s of little reassurance, given the speed at which it spreads. Hospitals in many parts of the country are already at or near capacity. A tsunami of new cases could lead to a sharp decline in the quality of care for all. And even if the death rate stays stable, an increase in cases will fuel the already enormous death toll in this country.

As of Friday, roughly 390,000 people have died from Covid-19 in the country. That death toll has risen dramatically in recent weeks, with 45,000 deaths occurring since the beginning of January.

Butler said there is no evidence the current surge of cases in many parts of the country is due to the new variant.

The modeling effort estimated that without the new variant and with an effective rollout of vaccine, the rate of new cases in the country should have started to decline in February and March. But the vaccine rollout is not going smoothly, vaccine supplies are limited and will remain so for weeks, and now, there is a new variant to contend with.

“Efforts to prepare the health care system for further surges in cases are warranted,” the authors of the article cautioned.

Additional variants that appear to be more transmissible have been reported from South Africa and from Brazil. To date, there is no evidence they are spreading in the United States yet, the article noted.