Gov. Charlie Baker expects a state-sanctioned COVID-19 vaccination passport program to be implemented in Massachusetts and several other states soon.

During an appearance on GBH News' Boston Public Radio, Baker said a scannable quick response code, commonly known as a QR code, would show a person's vaccination status and be made available for others to scan and verify.

"It's a universal standard and we've been working with a bunch of other states, there's probably 15 or 20 of them, to try to create a single QR code that can be used for all sorts of things where people may choose to require a vaccine," Baker said of the passport program.

Baker showed hosts Margery Eagan and Jim Braude his code while in the GBH’s studios in Brighton.

"It's my proof that I've been vaccinated," he said.

Last week, new Boston Mayor Michelle Wu hinted that the city may implement a vaccine mandate for indoor recreation areas.

Baker defended the availability of COVID booster shots in the state, saying Massachusetts is providing around 55,000 total vaccination shots per day, including boosters, and has administered around 1 million booster shots. Baker compared that figure to the 80,000 doses the state was outputting last spring at the height of the vaccination push with the help of mass vaccination centers.

Baker said booster vaccines are available, but may not be in the most convenient locations for everyone.

"Now, they may not be in the place somebody wants to go to get one. And it may be a week or 10 days out or two weeks out before they can get one. But given the fact that we have far more demand now that we had a couple of weeks ago, we're going to see if we can increase our capacity to do more," Baker said.

When the conversation turned to politics, Baker once again told Braude that he's close to deciding whether to run for a third term, and that if he does, it will likely be as a Republican.

Braude told the governor that he assumes if Baker runs again, he "will run as a Republican or won't run at all."

"I think that's a reasonable assumption to make," Baker replied.

A Democrat-funded poll earlier this month found that Baker could face stiff competition in next year's Republican primary against the more conservative, Trump-aligned candidate former Whitman Rep. Geoff Diehl.

Baker said he doesn't sit around and think to himself about if he can win a race.

"To me, the question always comes back to what I said to you before, which is do I have the will, the desire and the agenda that I believe would be in the state's best interest, and the energy and the commitment to follow through and deliver on it," Baker said.

Asked about Maine's recent rejection of plan Baker favors to locate a power transmission line from Quebec to the United States to transmit hydroelectricity, the governor said he's having conversations with utilities and the province of Quebec over what to do to salvage the plan.

"We're still working on it with CMB, Central Maine Power and the folks in Quebec," Baker said.

Baker said the ballot question passed by Maine voters rejecting the transmission line through woodlands raises "an important legal question" about whether major projects, already approved by state governments, can be subject to changes made by voters.