The United States has donated more than 400m vaccine doses to 112 countries, marking a major milestone in the White House's goal of donating 1.2bn vaccine doses under Joe Biden's direction.
In a press briefing on Wednesday, the White House Covid-19 response coordinator, Jeff Zients, said the donation is four times larger than that of any other country.
Zients also revealed that the country hit another major milestone this week, with 70% of eligible seniors in the US having now received their booster shot. Half of all eligible adults in the country are now boosted.
"This is significant progress, as the doctors and data have made crystal clear. Vaccinations and boosters provide the best protection," Zients said.
The daily averages of cases and hospital admissions have fallen over the past week, according to the Centers for Disease Control and Prevention (CDC).
The current seven-day average of Covid-19 cases is approximately 692,400 cases a day, a 6% decrease from the previous week, while the seven-day average of hospital admissions is about 19,800 a day, an 8% decrease.
However, the figure for seven-day average daily deaths is about 2,200 a day, an increase of 21%.
"These data demonstrate that Covid-19 disease severity appears to be lower with the Omicron variant than with prior variants," saidDr Rochelle Walensky, director of the CDC. "Although it's encouraging that Omicron appears to be causing less severe disease, it is important to remember that we are still facing a high overall burden of disease.
"Milder does not mean mild," the director added. "Now is the time to do what we know works: wear a mask, get vaccinated and get boosted."
Speaking at the press briefing, Dr Anthony Fauci, director of the National Institute of Allergy and Infectious Disease, said that scientists have been working on developing a "pan-coronavirus" vaccine, in order to induce "broad and durable protection against coronaviruses that are known, and some that are even at this point, unknown".
Nevertheless, those vaccines would take years to develop, he said. "I don't want anyone to think that pan-coronavirus vaccines are literally around the corner in a month or two."
Zients also told reporters that approximately 85% of the Covid-19 antiviral pills that the US has purchased has been directly distributed to states. This has been done "the same way we distribute vaccines - for them to then put the pills in the most important places within their states, at local hospitals and health systems and other caregivers", Zients said.
The remaining 15% will be distributed directly to community health centers around the country, he added.
Earlier this month, Biden announced that the US would purchase 20m of Pfizer's Covid-19 antiviral pill Paxlovid, doubling its previous order of 10m. In data released by Pfizer last December, the pill was estimated to have reduced the risk of hospitalization or death due to Covid by 89% in high-risk adults.