The United States will offer tax credits to businesses that grant their employees time off to receive a Covid-19 vaccine or recover from its side effects, the Treasury Department said on Wednesday.

The credits are aimed at companies and tax-exempt organizations with fewer than 500 employees, as well as some government offices, and are paid for by the $1.9 trillion American Rescue Plan President Joe Biden signed last month.

"Eligible employers may claim tax credits for sick and family leave paid to employees, including leave taken to receive or recover from Covid-19 vaccinations, for leave from April 1, 2021, through September 30, 2021," according to details of the credits published by the Internal Revenue Service (IRS).

Biden, who took office in January, is pushing for Americans to get the jabs protecting against Covid-19 to end the world's largest outbreak and accelerate the economy's recovery after the pandemic caused tens of millions of layoffs and a sharp downturn in growth last year.

On Wednesday, the White House announced that the United States would by the end of this week hit Biden's target of administering 200 million vaccine doses within his first 100 days.

The achievement comes in slightly ahead of schedule, with Biden marking his 100th day in office at the end of next week.

While the United States leads the world in Covid-19 deaths, it has also raced ahead in the vaccination stakes, outperforming some major European countries and neighbouring Canada.

However, parts of the country are seeing new infections surge, including Michigan, even as death rates remain down nationwide as a result of improved care and high vaccination rates among the elderly.