BOSTON — In his annual State of the Commonwealth address, Republican Gov. Charlie Baker defended his vaccine distribution plan, which some have criticized for being confusing and too narrowly focused at first.

Baker said the state is prepared to distribute and administer all the vaccine shots delivered by the federal government and is rapidly expanding the number of vaccination sites.

“Vaccinating 4 million adults in Massachusetts as the doses are allocated by the federal government is not going to be easy. But be assured that we will make every effort to get this done as quickly and efficiently as possible,” he said. “We can only move as fast as the federal government delivers the vaccines.”