President Biden to ABC's David Muir on at-home COVID testing: 'Nothing's been good enough'

President Joe Biden said Wednesday in an exclusive interview with ABC "World News Tonight" anchor David Muir that when it comes to the availability of at-home coronavirus tests in the United States, "nothing's been good enough."

"We're nearly two years into this pandemic, you’re a year into the presidency, empty shelves and no test kits in some places three days before Christmas when it's so important," Muir asked Biden during a sit-down interview at the White House. "Is that good enough?"

"No, nothing’s been good enough," the president replied. "But look, look where we are. When last Christmas, we were in a situation where we had significantly fewer vaccinated -- people vaccinated, emergency rooms were filled. You had serious backups in hospitals that were causing great difficulties. We’re in a situation now where we have 200 million people fully vaccinated. Two hundred million people fully vaccinated. And we have more than that who have had one shot, at least one shot. And they’re getting these booster shots as well."

The president this week announced new plans to slow the spread of the omicron variant of the coronavirus, including purchasing 500 million at-home rapid tests and, starting next month, distributing them to Americans, free of charge.

The highly transmissible variant became the most dominant COVID strain in the country on Monday, and has threatened to upend the Christmas holiday for millions of Americans.

Muir pressed Biden on why tests were not available before the Christmas rush, with the omicron variant now detected in all 50 states.

"Three days before Christmas, if you look out across the country, you see it everywhere, these long lines, people waiting for hours outside in the cold, just to get tested, to be reassured before they spend time with their family," Muir said. "If you go to the pharmacy, we hear this over and over again, empty shelves, no test kits. Is that a failure?"

"I don't think it's a failure," Biden replied. "I think it's -- you could argue that we should have known a year ago, six months ago, two months ago, a month ago."

But he did express some regret about not ordering the rapid, at-home tests sooner.

"I wish I had thought about ordering" 500 million at-home tests "two months ago," he told Muir.

The president has sought to both reassure Americans that vaccinations and booster doses protect against serious illness and death.

Israel said this week it was preparing to administer a fourth dose to some of its citizens.

Asked by Muir about this development, Biden said "there may be a need for another booster, but that remains to be seen."

"So it remains a possibility?" Muir pressed.

"It remains a possibility," the president said.

While the Biden administration has required foreign visitors flying to the United States to be vaccinated against COVID-19 -- with some exceptions, like for those on immigrant visas -- he has so far resisted mandating vaccination for domestic air travel.

As millions of people travel home as omicron spreads across the country, Muir asked the president: "Have you considered requiring passengers in this country to be vaccinated to get on flights?"

"It's been considered but the recommendation I've gotten, it's not necessary," Biden said.

"Even with omicron?" Muir asked.

"Even with omicron," Biden said. "That's the recommendation I got so far from the team."

On Thursday, a reporter pressed White House press secretary Jen Psaki on Biden's comments, and the logic of requiring vaccinations for foreign visitors but not for domestic air passengers.

She suggested the difference related to keeping new variants out of the United States.

"In terms of international travel, part of the effort is--has been related to the number of variants that are out there, and we see them differently," Psaki said. "Rules, as you know, for international travelers are different because international travelers must be vaccinated and tested within one day of departure to help keep COVID cases out of this country and delay any new possible variant from coming into the country."

But some public health experts believe instituting a vaccine mandate for domestic travel would blunt the spread of the virus in the United States; omicron has already reached every state.