• President Joe Biden received a Covid-19 booster shot Monday, in accordance with the latest guidance from the Centers for Disease Control and Prevention.
• At 78 years old, Biden qualified for the additional shot under new guidance issued last Friday. Biden received his first vaccine shot late last year.
• The World Health Organization opposes a widespread rollout of booster shots, saying wealthier nations should give extra doses to countries with minimal vaccination rates.

President Joe Biden received a Covid-19 booster shot Monday, in accordance with the latest guidance from the Centers for Disease Control and Prevention.

At 78 years old, Biden qualified for the additional shot under new guidance issued late last week. Biden received his first Pfizer vaccine shot late last year, and his second shot in January.

"Boosters are important, but the most important thing we need to do is get more people vaccinated," Biden said prior to receiving his injection.

"The vast majority of Americans are doing the right thing. Over 77% of adults have gotten at least one shot," he said. "About 23% haven't gotten any shots. And that distinct minority is causing an awful lot of damage for the rest of country. This is a pandemic of the unvaccinated. That's why I'm moving forward with vaccination requirements wherever I can."

CDC Director Dr. Rochelle Walensky on Friday authorized the distribution of Pfizer and BioNTech's Covid-19 booster shots for those in high-risk occupational and institutional settings, a move that overruled an advisory panel.

Walensky also approved distributing booster shots to older Americans and adults with underlying medical conditions at least six months after their first series of shots, in line with the advisory panel.

Senate Minority Leader Mitch McConnell, 79, announced Monday afternoon that he had also received a booster shot, and urged eligible Americans to join him in getting the shot.

The Kentucky Republican's statement on the Senate floor was noteworthy given the partisan divide that runs through the U.S. vaccination rate. An August NBC News poll found that 88% of Democrats reported having been vaccinated, versus only 55% of Republicans.

The World Health Organization opposes a widespread rollout of booster shots, saying wealthier nations should give extra doses to countries with minimal vaccination rates.

Biden defended the U.S. decision to offer booster shots Monday, saying America does more than any other country in the world to distribute vaccines to poorer countries.

"We're gonna do our part," he said. "We've also given a great deal of funding to COVAX, which is the vehicle that [provides vaccines to underserved parts of the world]. So, we have plenty, plenty of opportunity to make sure we get everyone in the world ... vaccinated."

Roughly 60 million of the 100 million Americans who originally received the Pfizer-BioNTech Covid vaccine are now eligible for a third shot as the highly contagious delta variant continues to tear across the country, including health-care workers, teachers, grocery store employees and other essential workers.

The CDC's final decision allows Biden to claim victory, even though he didn't get everything he wanted. The administration said it planned to start giving booster shots to people 16 and older this month.

While the CDC panel's recommendation doesn't give the Biden administration everything it wanted, boosters will still be on the way for millions of Americans who originally received Pfizer's shots.

Roughly 2.6 million Americans have received extra doses of a Covid vaccine since health officials authorized administering extra shots of Pfizer or Moderna's vaccines to people with weakened immune systems in August, according to data compiled by the CDC.

Some scientists, including at least two at the FDA, had said they weren't entirely convinced every American who has received the Pfizer vaccine needed extra doses at this time.