President Joe Biden on Thursday announced his administration has "now purchased enough vaccine to vaccinate all Americans"—but he cautioned that logistical challenges may mean most Americans won't be vaccinated until the end of the summer.

Radio Advisory episode: Biden's plan for fighting Covid-19

Biden admin finalizes deals for extra vaccine doses

CDC data shows that, as of Thursday morning, the federal government had distributed about 68.2 million doses of the United States' two authorized Covid-19 vaccines—one created by Pfizer and BioNTech, and another created by Moderna.

Each of the vaccines require that patients receive two doses a few weeks apart. According to CDC's data, as of Thursday morning, about 34.7 million Americans had received "one or more doses," and about 11.2 million had received two doses.

The Biden administration in recent weeks has taken several steps to speed up vaccinations. For example, the Biden administration last month announced plans to increase America's vaccine supply by purchasing additional doses of authorized Covid-19 vaccines.

During an appearance at NIH on Thursday, Biden said his administration has finalized the agreements with Pfizer and Moderna to purchase an additional 100 million doses of each of the companies' vaccines.

Those additional 200 million doses will increase America's total vaccine order by 50%, from 400 million doses to 600 million doses, which would be enough doses to fully vaccinate 300 million Americans. According to the Washington Post, an estimated 260 million people in the United States are currently eligible to receive Covid-19 vaccine.

Biden said the federal government expects to receive some of those doses sooner than expected—with the government receiving enough vaccine doses to vaccinate 200 million Americans under the two-dose regimen by the end of May, the Post reports. The federal government is expected to receive the entire order of additional doses by the end of July, the Post reports. 

However, Biden acknowledged the federal government will face logistical challenges as it tries to get Americans vaccinated. Biden said his administration is "working to get those vaccines into the arms of people," citing, for instance, collaborations with the National Football League to turn its stadiums into inoculation sites.

Fauci says all Americans could become eligible for vaccines as soon as April

During an interview with NBC's "Today," Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases and the chief medical adviser for the Biden administration's Covid-19 response efforts, said most Americans could become eligible for the Covid-19 vaccine as early as April.

"As we get into March and April, the number of available doses will allow for much more of a mass vaccination approach," Fauci said during the interview.

According to the Times, states have so far been prioritizing vaccine doses for groups of Americans at high risk for contracting the virus.

Fauci noted that, even after more Americans become eligible for the vaccine, it would take "several more months" to get the vaccines into most people's arms. Still, Fauci said he expects the pace of the vaccine rollout to pick up, in part because of efforts to allow community health centers and pharmacies to administer Covid-19 vaccines.

The White House on Tuesday announced the federal government will begin directly shipping vaccine doses to federally qualified community health centers next week.

And beginning on Friday, the federal government will deliver vaccine doses directly to drugstores and grocery store pharmacies, the New York Times reports. According to the Times, the federal government will start by distributing one million vaccine doses to nearly 6,500 retail pharmacies. The government will eventually expand the program to include up to 40,000 retail pharmacies, the Times reports.

Where America's coronavirus epidemic stands

The announcements come as data from the past two weeks indicates America's coronavirus epidemic has improved since last month's peak in cases, hospitalizations, and deaths. However, the reported rates of each of those metrics remain high, and experts say the epidemic's recent progress is on shaky ground because of newly emerging coronavirus variants and some states' moves to scale back social distancing restrictions.

According to data compiled by the Times, U.S. officials on Thursday reported about 105,515 new coronavirus cases. As of Friday morning, officials had reported a total of about 27.4 million cases since the epidemic began.

According to the Times, the United States' average daily number of newly reported coronavirus cases over the past week was 101,655—down by 36% when compared with the average from two weeks ago, when the United States was in the midst of its worst peak 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 Alaska, which 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, Michigan, Minnesota, North Dakota, Oregon, Puerto Rico, U.S. Virgin Islands, Washington, and Wyoming.

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 Wednesday, but were down by about 8% last week when compared with the previous week, Axios' "Vitals" reports. According to data from The Atlantic's COVID Tracking Project, there were 74,225 Americans with Covid-19 hospitalized for treatment on Thursday, including 15,190 who were receiving care in an ICU and 4,970 who were on a ventilator. Thursday marked the eighth consecutive day that fewer than 90,000 Americans with Covid-19 were hospitalized for treatment.

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 "Vitals," the number of newly reported deaths linked to the coronavirus in the country dropped by 3% last week when compared with the previous week.

According to data from the Times, U.S. officials reported about 3,878 new deaths linked to the virus on Wednesday. As of Friday morning, officials had reported a total of about 475,224 U.S. deaths linked to the virus since the country's epidemic began.

(Rogers/Weiland, New York Times, 2/11; Choi/Kambhampaty, Politico, 2/11; Knutson, Axios, 2/11; Stanley-Becker et al., Washington Post, 2/11; Romo, NPR, 2/11; Weixel, The Hill, 2/11; Weixel, The Hill, 2/11; Fortin, New York Times, 2/11; Money/Lin, Los Angeles Times, 2/11; New York Times, 2/12; New York Times, 2/12; "COVID Tracking Project," The Atlantic, accessed 2/12).