Covid-19 Variants Could Fuel Another Surge.

Covid-19 variants are threatening to cause another surge of infections, health officials warned Wednesday, and it's now more important than ever for Americans to continue practicing safety measures that work against the spread of the virus.

"The continued spread of variants that are more transmissible could jeopardize the progress we have made in the last month if we let our guard down,"

Centers for Disease Control and Prevention Director Dr. Rochelle Walensky said during a White House briefing. But by lowering cases, the US will give "fewer opportunities for the variants to spread and fewer opportunities for new variants to emerge," she added.

A customer wears a face mask while shopping for flowers displayed for sale from a wholesale merchant ahead of the Valentine's Day holiday at the Southern California Flower Market on February 12, 2021 in Los Angeles, California It's a warning that's been repeated by multiple experts recently as the country's tally of variant cases keeps climbing while more state leaders are opting to loosen Covid-19 restrictions.

Among the most concerning strains is the highly contagious B.1.1.7 variant, first identified in the UK, that the CDC has previously warned could become "the predominant variant in March."

The agency has reported more than 1,270 cases of the variant across 41 states and Washington, DC. But the US has two powerful tools that can help against its spread and move the country further out of the pandemic's tunnel, Dr. Anthony Fauci told CNN on Wednesday night.

"The two ways that we can counter that is one, continue to do the kinds of public health interventions that we talk about all the time," he said. That includes the universal wearing of masks, social distancing, staying away from crowded areas and regular hand washing.

"But also, as the weeks and months go by, as you vaccinate more and more people, you have a vaccine that works against this variant," Fauci added. "So if we roll out the vaccine ... and get as many people vaccinated as quickly as we possibly can while we maintain the public health measures, we should be in good stead."

It won't be easy, he cautioned, because of the variant's transmissibility -- which is why "we have to act quickly on that," Fauci said. And lab studies offered more encouraging news this week, suggesting the Pfizer and Moderna vaccines can protect against Covid-19 variants.