The changes come amid public frustration about the pace of vaccinations and confusion about the process of who is eligible and limited number of appointments available to be vaccinated.
Over 63,000 doses were shipped out on Tuesday, and some 2 million doses are expected to be delivered to Germany's 16 federal states by the end of March, according to the German Ministry of Health.
As a result, he said, the Trump administration is now asking states to vaccinate people age 65 and over and those under 65 with underlying health conditions that put them at high risk.
"This is just a staging, moving to the next phase on the vaccine program", Azar said.
"We now believe that our manufacturing is predictable enough that we can ensure second doses are available for people from ongoing production", Azar told ABC's "Good Morning America". "We've got to get it to pharmacies, get it to community health centers".
He said the federal government "will deploy teams to support states doing mass vaccination efforts if they wish to do so".
The Serum Institute of India is the world's largest vaccine manufacturer.
But the slow pace of the vaccine rollout has frustrated many Americans at a time when the coronavirus death toll has continued to rise.
U.S. Surgeon General Jerome Adams said hundreds of thousands of people are getting vaccinated every day across the nation, but the pace of inoculations needs to improve.
"We have product that is going through QC right now - quality control - for sterility, identity check that we have tens and tens of millions of product".
With its Pfizer-partnered COVID-19 vaccine authorized in the U.S., Europe, the United Kingdom and a slate of other countries, German mRNA specialist BioNTech is wasting no time scaling up its 2021 pandemic ambitions-namely, 2 billion shots by year-end, plus a slate of new approvals and a temperature-stable formulation, too. Aside from extending Comirnaty's patient reach, BioNTech is plotting further stability testing for its current formulation-shackled by stringent cold chain requirements-plus a formula free of polyethylene glycol, which may be linked to side effects, and a more temperature-stable version of the shot.