Some officials are already expanding the groups of residents who are eligible to receive a Covid-19 vaccine in their states, but experts say the expansions could lead—and in some states, already have led—to an unmanageable spike in demand for the vaccines and to lower-risk Americans receiving the vaccine before those at higher risk of severe Covid-19.

Related: The U.S. Covid-19 vaccination scenario planning guide

America's vaccine rollout off to a slow start

Covid-19 vaccine distribution throughout the United States has been slower than expected so far. CDC data shows that, as of Friday morning, the federal government had distributed about 22.1 million doses of the Covid-19 vaccines currently authorized for use in the United States.

However, the data also shows that a vast majority of those doses hadn't yet been administered to Americans. According to the data, about 6.7 million Americans had received their first doses of the two-dose Covid-19 vaccines as of Friday morning.

To speed things up, some states broaden who's eligible for Covid-19 vaccines

Currently, CDC guidelines recommend that states first prioritize inoculating health care workers as well as residents and staff in long-term care facilities. The guidelines suggest that, once that first priority group is vaccinated, states then move on to vaccinating certain essential workers and people ages 75 and older.

However, to speed up the nation's vaccine rollout, some federal officials are urging states to focus on vaccinating as many people as possible rather than closely following CDC's recommendations.

For example, during an event held by the Alliance for Health Policy on Friday, FDA Commissioner Stephen Hahn called on state officials to allow lower-priority patients to receive Covid-19 vaccinations if the doses those patients receive would have gone to waste otherwise, The Hill reports. "I would strongly encourage that we move forward with giving states the opportunity to be more expansive in who they can give the vaccine to," Hahn said.

For instance, Hahn said he thinks "it's reasonable" to expand vaccinations to other groups—such as essential workers, first responders, or people older than 65—because the ultimate goal is to vaccinate as many Americans as possible.

Similarly, HHS Secretary Alex Azar on Wednesday said state officials should focus on getting vaccine doses out as quickly as possible, even if they haven't yet vaccinated every health care worker and long-term care resident. "Right now, there is no reason that states need to complete, say, vaccinating all health care providers, before opening up vaccinations to older Americans or other, especially vulnerable populations," he said.

According to Reuters, at least 16 states—Alabama, Alaska, Arizona, Colorado, Florida, Georgia, Indiana, Louisiana, Michigan, Mississippi, North Carolina, Oklahoma, Tennessee, Texas, West Virginia, and Wyoming—so far have either started or will soon allow older Americans who don't fall into the first priority group to get vaccinated against Covid-19 in some of all of their counties. In Florida, Georgia, and Texas, for example, adults ages 65 and older are eligible for vaccinations, while in Indiana and West Virginia, vaccinations are available to adults ages 80 and older.

Experts note there are upsides—and potential downsides—to expanding vaccine eligibility

Public health experts say there are both upsides and potential downsides to expanding Covid-19 vaccine eligibility this early in the United States' distribution process. For example, experts say expanding who is eligible to receive Covid-19 vaccines may mean fewer vaccine doses go to waste and a broader swath of America's population could be protected against Covid-19.

However, experts also note that distributing the country's limited supply of the vaccines among a larger share of the country's population will be far from easy—and it could result in some inequities.

In Florida, Texas, and some other states, officials are struggling to keep up with expanded demand for Covid-19 vaccines among older adults—with a number of their vaccination sites having to turn people away after running out of supplies.

In addition, state and county officials have had difficulty setting up appointment systems for people to schedule their vaccinations. In Florida, for instance, health department offices in Sarasota and other counties had to use Eventbrite—a website typically used for invitations to social events—for residents to schedule vaccine appointments because they didn't have a system to do so on their own websites, the New York Times reports.

Leslie Beitsch, chair of the behavioral sciences and social medicine department at Florida State University, said, "It's not in any way surprising—to anyone who followed it closely, for sure—that there would be halting kind of progress and missteps getting something of this magnitude underway initially, whether we're talking about Florida or the entire country."

In addition, some public health experts caution that the varying eligibility standards by state could create inequities in who is able to access the vaccines. Ultimately, that could lead to some Americans who are at lower-risk of contracting the novel coronavirus or developing a severe case of or dying from Covid-19 getting vaccinated before higher-risk individuals, experts said.

Overall, Kevin Ault, an obstetrician at the University of Kansas Medical Center who serves on the advisory committee that developed CDC's prioritization guidelines, said it's reasonable for states to start vaccinating a broader share of their populations before they finish vaccinating health care workers and others in the first priority group. However, Ault said states need to be careful about how they're distributing the vaccines to ensure they're not worsening inequalities and taking on more than they can handle.

"Obviously if you're going to vaccinate that group you need to have a well-thought-out plan in hand," he said, referring to people ages 65 and older. "Having people camping out for vaccine is less than ideal, I would say."

America grapples with persistently high rates of new coronavirus cases, hospitalizations, and deaths

States are pushing forward with their vaccination efforts as America continues to see persistently high rates of new coronavirus cases, hospitalizations, and deaths—which could worsen over the next few weeks, because of Americans gathering with others over the recent holidays.

According to data compiled by the Times, U.S. officials as of Monday morning had reported a total of about 22.4 million cases of the novel coronavirus 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 254,866—which is up by 38% when compared with the average from two weeks ago.

As of Monday morning, data from the Times showed that the rates of newly reported coronavirus cases were "staying high" in Puerto Rico; Washington, D.C.; and every state except Hawaii. According to the Times, those territories and states have had a daily average of at least 15 newly reported cases per 100,000 people over the past week.

Hawaii has had comparatively low case rates, but it was seeing those rates "going up" as of Monday morning, according to the Times. In Guam and the U.S. Virgin Islands, meanwhile, rates of newly reported coronavirus cases were "staying low" as of Monday morning, the Times' data showed.

U.S. hospitalizations for Covid-19, the disease caused by the novel coronavirus, also remained high on Sunday, according to data from The Atlantic's COVID Tracking Project. The data showed that 129,229 Americans with Covid-19 were hospitalized for treatment on Sunday, including 23,625 who were receiving care in an ICU and 7,782 who were on a ventilator.

As of Monday morning, U.S. officials had reported a total of about 374,428 U.S. deaths linked to the novel coronavirus since the country's epidemic began.