CDC as of Thursday reported 618 cases of novel coronavirus variants across 33 U.S. states, and although America's coronavirus epidemic has shown signs of improvement over the past week, experts worry the new variants could threaten that progress.

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America's coronavirus epidemic shows signs of improvement

Data from the past week indicates America's coronavirus epidemic is improving when compared with the peak in new coronavirus cases, hospitalizations, and deaths the country experienced last month—though the reported rates of each of those metrics remain high.

According to data compiled by the New York Times, U.S. officials on Thursday reported about 126,842 new cases of the novel coronavirus. As of Friday morning, officials had reported a total of about 26.7 million case of the virus since America's epidemic began.

According to the Times, the United States' average daily number of newly reported coronavirus cases over the past week was 130,953—which is down by 30% when compared with the average from two weeks ago, when the United States was in the midst of its worst peak yet in newly reported cases.

As of Friday morning, data from the Times showed that the rates of newly reported coronavirus cases were "staying high" in Montana, South Dakota, and Vermont, which have each reported a daily average of at least 15 newly reported cases per 100,000 people over the past week. In contrast, rates of newly reported coronavirus cases were "staying low" as of Friday morning in Guam, Hawaii, North Dakota, Puerto Rico, and the U.S. Virgin Islands.

All other states and Washington, D.C., had been seeing comparatively higher rates of coronavirus transmission, but the daily average of newly reported coronavirus cases over the past seven days in those areas was "going down" as of Friday morning, according to the Times' data.

U.S. hospitalizations for Covid-19, the disease caused by the novel coronavirus, remained high as of Thursday, but still were down significantly from record-highs reported last month. According to data from The Atlantic's COVID Tracking Project, there were 88,668 Americans with Covid-19 hospitalized for treatment on Thursday, including 17,918 who were receiving care in an ICU and 5,732 who were on a ventilator.

Similarly, the United States' rate of newly reported deaths linked to the novel coronavirus has declined over the past two weeks, though it also remains high. According to data from the Times, U.S. officials reported about 5,116 new deaths linked to the virus on Thursday. As of Friday morning, officials had reported a total of about 455,805 U.S. deaths linked to the virus since the country's epidemic began.

New coronavirus variants threaten progress

While the data indicate that America's coronavirus epidemic is beginning to ease, experts say the prospect of continued progress is on shaky ground for two main reasons.

First, until a significant majority of Americans are vaccinated against Covid-19, stopping the coronavirus' spread will largely depend on Americans' adherence to mitigation measures such as wearing face masks, physical distance, and limiting indoor gatherings with people outside of their households. And with a substantial number of Americans reporting that they'd attend Super Bowl gatherings on Sunday, experts worry we could see another spike in new coronavirus cases, hospitalizations, and deaths tied to the event.

Second, health experts worry that the spread of new, more-contagious coronavirus variants in the United States could threaten recent progress in the epidemic, particularly because research suggests some of the new variants could be less susceptible to current Covid-19 vaccines.

According to CDC data, the United States as of Thursday reported 618 cases of novel coronavirus variants across 33 U.S. states. That total includes:

• 611 cases of the B.1.1.7 variant first identified in the United Kingdom, which research suggests is both more transmissible, potentially more deadly, and possibly less susceptible to vaccines than earlier variants of the virus;
• Five cases of the B.1.351 variant first identified in South Africa, which research suggest is more transmissible and less susceptible to vaccines than earlier variants of the virus; and
• Two cases of the P.1 variant first identified in Brazil, which research suggest is more transmissible and less susceptible to vaccines than earlier variants of the virus.

On Wednesday, CDC Director Rochelle Walensky said, "Although we have seen declines in cases and admissions and a recent slowing of deaths, cases remain extraordinarily high, still twice as high as the peak number of cases over the summer. And the continued proliferation of variants, variants that likely have increased transmissibility, that spread more easily, threatens to reverse these recent trends." She added, "Based on contact tracing of recent variant cases, not wearing masks and participating in in-person social gatherings have contributed to the variants' spread."

FDA announces new moves to address coronavirus variants

To help curb these new coronavirus variants' spread, experts say Americans must double down on preventive public health measures, U.S. officials must focus on getting as many Americans vaccinated against Covid-19 as possible, and researchers and vaccine developers must take steps to ensure Covid-19 vaccines will protect against the new variants.

CDC data shows that, as of Thursday morning, the federal government had distributed about 57.5 million doses of the United States' two authorized Covid-19 vaccines, which are manufactured by Pfizer and BioNTech, as well as Moderna. Each of the vaccines require that patients receive two doses of the inoculations a few weeks apart.

According to CDC's data, a total of about 35.2 million doses of the vaccines had been administered to Americans as of Thursday morning. Of those, about 27.9 million Americans had received "one or more doses," and about 6.9 million had received two doses, the data shows.

On Thursday, FDA Acting Commissioner Janet Woodcock announced that the agency is developing guidance aimed at helping manufacturers of coronavirus tests and Covid-19 treatments and vaccines adapt to emerging variants of the virus.

For example, Woodcock said FDA is working to establish an expedited review process for booster shots or changes to Covid-19 vaccines that are intended to bolster the vaccines' efficacy against new variants. The agency likely will release a proposal outlining that process within a few weeks, and it will be open for public comment, Woodcock said.

"It'll … provide the scientific community and public (a chance to) comment on what we're thinking, and perhaps we can refine our thinking," she said.

For the meantime, Woodcock noted that research suggests the United States' authorized coronavirus vaccines still are highly effective against the new variants, even if they are slightly less effective against the new variants in comparison to earlier variants of the virus.

Overall, Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases and chief medical adviser to the White House's Covid-19 response team, separately said that Americans should continue practicing measures such as physical distancing, avoiding crowded indoor spaces, and wearing masks, and they should get vaccinated against Covid-19 when they can.

"Viruses cannot mutate if they don't replicate," he said. "And if you stop their replication by vaccinating widely and not giving the virus an open playing field to continue to respond to the pressures that you put on it, you will not get mutations" (Aspegren/Miller, USA Today, 2/5; CDC variant cases data, 2/4; New York Times, 2/5; "COVID Tracking Project," The Atlantic, accessed 2/5; "COVID Tracking Project," The Atlantic, 2/4; Frellick, Medscape, 2/4; CDC Covid-19 vaccine data, 2/4; Humer, Reuters, 2/4; Weintraub, USA Today, 2/5; Owermohle/Lim, Politico, 2/4).