US President Joe Biden gets Covid-19 vaccine booster shot

Biden rolled up his left sleeve in the White House and got a third Pfizer dose in line with the recently approved health guidance, which allows boosters for those 65 or older.

"I know it doesn't look like it, but I am over 65," Biden, 78, joked.Also eligible for boosters are adults with high-risk medical conditions and those in jobs where they are frequently exposed to the virus.

But the problem, Biden said, is that a significant chunk of Americans continue to refuse even one shot of the vaccine, fueling a deadly nationwide surge of the Delta variant. Biden said 77 percent of Americans had got vaccines but this wasn't enough, with still nearly a quarter refusing.