CNN  — 

With every Covid-19 vaccination, the United States inches closer to defeating the pandemic that has killed over half a million Americans and left countless more with long-term complications.

But major challenges stand in the way. Some Americans are ditching personal responsibility and forgoing masks, even though the highly contagious B.1.1.7 variant has spread to at least 46 states and Washington, DC.

“That strain is increasing exponentially. It’s spiking up,” said Dr. Celine Gounder, an infectious diseases specialist and epidemiologist. “So we are probably right now on a tipping point of another surge.”

Research shows that in the US, the B.1.1.7 variant is 59% to 74% more transmissible than the original novel coronavirus.

And the current rate of vaccinations might not be fast enough to fend off a major B.1.1.7 surge in the coming weeks.

“At 2.9 to 3 million doses of vaccine a day over the next six to 14 weeks, when this surge is likely to happen, is not going to really take care of the problem at all,” Michael Osterholm, director of the University of Minnesota’s Center for Infectious Disease Research and Policy, told NBC’s “Meet the Press” on Sunday.

Osterholm said the US should take a lesson from Europe, which has struggled with the B.1.1.7 strain after it was first detected in the United Kingdom.

Just one month ago, B.1.1.7 made up around 4% of coronavirus cases in the US, among those that have undergone genomic sequencing. “Today, it’s up to 30 to 40%,” Osterholm told NBC on Sunday. “And what we’ve seen in Europe, when we hit that 50% mark, you’ll see cases surge.”

Still hovering at very high numbers

After weeks of declines, new Covid-19 cases have basically plateaued at high levels each day.

On average, more than 60,000 Americans were infected every day over the past week, according to Johns Hopkins University. That’s slightly less than the peak of the summer surge, when 67,030 infections were reported on July 20.

The US shouldn’t loosen coronavirus restrictions until daily new cases fall below 10,000, said Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Disease.

He said it’s “inexplicable” that some states are rolling back safety measures such as mask mandates, when masks are needed to help fend off B.1.1.7 and other concerning variants.

“I understand the need to want to get back to normality, but you’re only going to set yourself back if you just completely push aside the public health guidelines – particularly when we’re dealing with anywhere from 55 (thousand) to 70,000 infections per day in the United States,” Fauci said.

Despite health leaders’ warnings, several state leaders announced they were easing Covid-19 restrictions.

Texas Gov. Greg Abbott announced last week he was lifting the statewide mask mandate and doing away with any capacity limits on businesses starting this Wednesday

Mississippi Gov. Tate Reeves also said he was lifting all county mask mandates and would allow businesses to operate at full capacity without any state-imposed rules.

Ohio Gov. Mike DeWine announced revisions to public health orders on Tuesday, including dropping a 300-person limit for events at banquet centers. On Thursday, he said that when the state reaches 50 cases per 100,000 people for two weeks, all health orders will be lifted.

Michigan Gov. Gretchen Whitmer unveiled a series of eased restrictions, including expanded capacity for restaurants, retail, gyms, stadiums and other facilities.

In Louisiana, Gov. John Bel Edwards also loosened restrictions. The majority of businesses – including restaurants and salons – are now allowed to operate at 75% capacity, while religious services no longer have capacity limits.

On Friday, Arizona Gov. Doug Ducey also said he was lifting occupancy limits on businesses – including restaurants, gyms and theaters.

West Virginia Gov. Jim Justice said restaurants, bars, gyms and museums could start operating at 100% capacity. Justice also upped the social gathering limit to 100 people.

South Carolina Gov. Henry McMaster issued an executive order Friday rescinding the face covering requirements in state government offices, buildings and facilities as well as in restaurants.

And in California, all of the state’s amusement parks, including Disneyland, Magic Mountain and Universal Studios along with sports and concert venues will be allowed to reopen with limited capacity starting April 1, Health and Human Services Secretary Mark Ghaly said Friday.

“We feel like now is the appropriate time to begin to reintroduce these activities in some fashion, and in a guarded way, in a slow and steady way,” Ghaly said.

We’re still months away from most Americans getting vaccinated

As of Sunday, more than 58.8 million Americans have received at least one dose of a Covid-19 vaccine.

About 30.6 million have received two doses of a vaccine. That’s about 9.2% of the US population.

Health experts say it’s critical to get as many people vaccinated as possible before highly contagious variants potentially overwhelm the country.

The good news: All three vaccines being used in the US “work really well” against the troubling B.1.1.7 variant, said Dr. Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine.

And research published Thursday shows the B.1.1.7 strain can hide a bit from the immune system, but not enough to decrease the value of vaccines significantly. And it doesn’t threaten to reinfect people who have recovered from the previous dominant strain of the virus.

“These findings indicate that variant B.1.1.7 is unlikely to be a major concern for current vaccines or for an increased risk of reinfection,” the researchers wrote in a report published in the journal Cell Host and Microbe.

So by doubling down on safety precautions and people getting vaccinated as soon as they’re able to, the US can defeat the B.1.1.7 strain and get back to normal life, faster.

CNN’s Nadia Kounang, Maggie Fox, Cheri Mossburg, Hollie Silverman, Heather Law and Konstantin Toropin contributed to this report.