(CNN) The emergence of Covid-19 variants makes reopening efforts in the United States a riskier proposition, an infectious disease expert said Wednesday.
Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota, said the B.1.1.7 variant has resulted in increased transmission in countries with vaccination efforts similar to the United States.
"Our only hope right now is that we as a country take this seriously and do whatever we can to limit transmission, as these other countries tried to do," he said during an event hosted by Axios.
"And, yet, at the same time I sit here and tell you we've never been more open as a country since the very first days of the pandemic."
Osterholm said efforts to reopen schools are "frustrating," as are recent guidelines that schools can maintain three feet of social distance as opposed to six feet.
"The transmission dynamics are going to change, and it won't be quite the same way that it was." Osterholm said. "We don't seem to care, in the sense that we're opening up everything at local, state, and even federal levels."
Since the start of the month, at least a dozen state leaders have eased Covid-19 restrictions.
On Tuesday, Indiana Gov. Eric Holcomb announced that starting April 6, the state's face-covering mandate will become a state mask advisory. Masks will remain mandatory in state buildings and facilities as well as at Covid-19 testing and vaccination sites, the governor said.
Also starting April 6, decisions about venue capacity will be in the hands of local officials, Holcomb said, and customers in restaurants, bars and nightclubs will no longer be required to be seated. Six feet of spacing between tables is still recommended, he added.
In Virginia, Gov. Ralph Northam announced Tuesday that starting April 1, both indoor and outdoor gathering limits will increase and certain sports and entertainment venues will be able to operate with additional capacity.
In less than two months, the pace of vaccination in the US has doubled.
Almost 130.5 million Covid-19 vaccine doses have been administered, according to data published Wednesday by the Centers for Disease Control and Prevention. The CDC reported that 130,473,853 total doses have been administered -- about 77% of the 169,223,125 doses delivered.
That's nearly 2.3 million more doses reported administered since Tuesday, for a seven-day average of about 2.5 million doses per day.
A month ago, the seven-day average was about 1.5 million doses per day, according to a CNN analysis of CDC data. On January 29, the seven-day average was 1,253,815 doses per day.
Vaccine eligibility across the US
Nearly 26% of the population -- almost 85.5 million people -- has received at least one dose of vaccine, and 14% of the population -- more than 46 million people -- are fully vaccinated, CDC data shows. A third of adults and about 70% of seniors have received at least one dose.
Philadelphia canceled thousands of Covid-19 vaccine appointments at its FEMA-run vaccination site after some residents used QR codes circulated online to schedule invalid appointments, according to the city's Department of Public Health.
The department has canceled approximately 11,000 vaccine appointments for this week and is in the process of reviewing appointments made for the upcoming two weeks, spokesperson James Garrow said. All told, the city may cancel as many as 30,000 appointments after its internal review.
The vaccination site had been scheduled to provide first doses for the first three weeks, followed by only second doses for the following three. The city was alerted to the invalid appointments after the site moved to its second-dose stage. Staff checked a vaccine database and "saw that names didn't match up," Garrow told CNN.
Site staff members had shared a QR code with people receiving their first dose so they could schedule a second appointment. That QR code was later found online, according to Garrow.
"We are going through the appointment database and matching it up with the vaccine database to see who is eligible for a second dose and then canceling all of the rest of the appointments," Garrow told CNN in an email.
"The vast majority of Philadelphians continue to follow the rules and wait for their turn in line. We understand how frustrating this wait is and are working as quickly as possible to get everyone vaccinated," Garrow said, warning that those who expect to receive their first dose at the site "should not walk up and expect to be vaccinated."
As more Americans are vaccinated, the number of people going out is also increasing, according to a poll from Axios-Ipsos published Tuesday.
Compared to a month ago, the number of people who have gone out to eat or visit friends and family are up 12 and 9 percentage points respectively, according to the poll -- which was conducted March 19 to 22 and was made up of 995 Americans 18 and older.
The number of people who believe that dining out poses a large risk to health and well-being has gone down to 23% compared to 33% a month ago.
Those who have visited friends or relatives -- 48% -- is the highest since October. Additionally, 54% have visited a non-grocery retail store -- the highest number since May.
Meanwhile, AstraZeneca is soon expected to apply for emergency use authorization for its Covid-19 vaccine in the US. But some experts fear recent concerns over an announcement of its vaccine data could further contribute to hesitancy.
AstraZeneca has updated its data on how well its vaccine works, saying late Wednesday the vaccine showed 76% efficacy against symptomatic coronavirus disease and 100% efficacy against severe or critical disease or the need for hospitalization.
On Monday, AstraZeneca had said its vaccine showed 79% efficacy against symptomatic disease and 100% efficacy against severe disease and hospitalization.
A day later, the National Institute of Allergy and Infectious Diseases issued a statement saying the independent board that reviews data from multiple vaccine candidates had concerns about the company's announcement.
The board "expressed concern that AstraZeneca may have included outdated information from that trial, which may have provided an incomplete view of the efficacy data," the NIAID statement said.
Speaking on ABC's "Good Morning America" on Tuesday, Dr. Anthony Fauci said the AstraZeneca news release may have contained misleading information about its vaccine efficacy -- "an unforced error" that may create doubt about what is likely a good vaccine.
The data is "really quite good, but when they put it into the press release, it wasn't completely accurate," Fauci said.
Cases of Covid-19, as well as hospitalizations and deaths are dropping fastest among seniors in the US, a CNN analysis shows.
The 65 and older population has seen a larger decline in case rates, death rates and hospitalizations than any other age group, and they're accounting for a smaller share of total hospitalizations than they were a few months ago, according to the analysis of data from the CDC.
Among people 65 and older, weekly hospitalizations have been steadily declining since the start of the year, dropping 83% over nine weeks between early January and mid-March, CDC data shows.
More than half of hospitalizations were among people 65 and older in early January, but that had dropped to about 37% by mid-March.
Hospitalization data from the CDC's COVID-NET surveillance system is preliminary.
Additional data tracked by the CDC shows that Covid-19 case rates among seniors were 83% lower in the first week of March than they were two months earlier, and death rates were about 96% lower, both steeper declines than in any another age group.
"Right now, as the weeks go by, we see more and more that not only are these vaccines efficacious but in the community they are extremely effective in preventing infection with SARS-CoV-2," Fauci said during a White House briefing on Wednesday.