Washington DC - The 200 millionth coronavirus vaccine shot was injected in the US on Wednesday – but President Joe Biden wasted no time on celebrations, instead rolling out a new financial incentive for those who have yet to get immunized.

The incentive comes in the form of a tax credit allowing businesses with fewer than 500 employees to fully offset the cost of providing upward of 80 hours, or 10 workdays, of paid time off for employees who need it to get the vaccine, Biden said.

The extensive span of paid time off is meant to give workers time to recover from any vaccination-related side effects without having to worry about missing a paycheck, Biden added.

"One concern I’ve heard from so many Americans is that they can't afford to take a day off to get vaccinated," Biden said at the White House.

"No working American should lose a single dollar from their paycheck because they chose to fulfill their patriotic duty of getting vaccinated."

He added: "We're calling on every employer, large and small, in every state: Give employees the time off they need with pay to get vaccinated."

The push for pumping out more vaccine came on the same day as the US reached Biden's goal of administering 200 million shots within his first 100 days in office.

"It's an incredible achievement for the nation" said Biden, who at first anticipated the US would inject 100 million shots within his first 100 days in office, but raised the stakes after that goal was met faster than expected.

Wednesday marked Biden's 91st day in office.

The 200 million milestone translates to about half of the American population getting at least one shot.

More than a third of all Americans are now fully vaccinated, according to data from the Centers for Disease Control and Prevention.

More than 80% of Americans over 65 have received at least one shot and other at risk demographics – like front-line workers and health care professionals – are showing similarly high immunization rates, CDC data shows.

But Biden said the US is now entering a challenging "new phase" in the race to vaccinate the country out of the pandemic that has killed more than 560,000 Americans.

Even though every state now allows anyone over 16 to get vaccinated, only about 43% of working Americans have received at least one shot, according to the CDC.

The low rate in that demographic appears to in part be a product of persistent vaccine hesitancy, especially among younger people, some communities of color and political conservatives.

The government is pouring hundreds of millions of dollars into outreach efforts aimed at counteracting such vaccine skepticism.

Biden stressed that it's critical for everyone – regardless of age – to get vaccinated, as inoculation isn't just about personal safety.

"Vaccines can save your own life, but they can also save your grandmother's life, your co-worker's life, the grocery store clerk or the delivery person helping you and your neighbors get through the crisis," Biden said. "That's why you should get vaccinated."

In addition to hesitancy, there has been a slight slowdown in inoculations in the US over the past week because of the "pause" placed on the Johnson & Johnson vaccine last week for a safety review launched after six women who received the shot developed potentially dangerous blood clots.

Public health officials say roughly 80% of the population needs to be fully vaccinated for the US to have a chance at achieving so-called "herd immunity."

Biden promised Americans last month that the country should be back to something that resembles normal by July 4.

On Wednesday, he suggested that timeline could be contingent on vaccinations continuing at a rapid clip.

"If you're waiting for your turn, wait no longer," he said.