There's no shortage of questions about how the Baker administration has approached its effort to vaccinate more than 4 million people. Legislators have critiqued everything from the governor's decision to allow healthy young people to get vaccinated alongside at-risk seniors to the delay in having a call center set up for people unable to book appointments online.

And after Thursday, both Democrats and Republicans want answers as to why the state's appointment website crashed, despite the predictable surge in traffic as people aged 65 and older were allowed to try to sign up for the first time.

Next week a legislative committee is seeking to get answers to those questions straight from the top, inviting Gov. Charlie Baker to testify before the panel at the first oversight hearing of the new Committee on COVID-19 and Emergency Preparedness, according to the Senate chair.

Sen. Jo Comerford, who is co-chairing the committee with Rep. William Driscoll, told the News Service in an interview Thursday that she doesn't know if Baker will accept the invitation to testify next Thursday.

"I hope he does," Comerford said. "We'd like to hear from him."

The committee has also invited Health and Human Services Secretary Marylou Sudders, Public Health Commissioner Monica Bharel, Assistant Public Health Commissioner Jana Ferguson and Assistant Public Health Commissioner and Director of the Bureau of Infectious Disease and Laboratory Sciences Kevin Cranston.

In addition, three other committees -- Health Care Financing, Public Health, and Racial Equity, Civil Rights and Inclusion -- have been asked to assemble expert panels to present to the oversight committee.

"What has caused such a turbulent vaccine rollout? The answer has been elusive, too elusive frankly," Comerford said.

"If the Legislature felt we were getting the answers that our constituents were demanding and we were demanding and if we were seeing a righting of the ship, perhaps we wouldn't have needed to form this committee," she continued.

A spokeswoman for Baker wouldn't say whether Baker planned to testify, pointing back to comments made by the governor during a Wednesday press conference when he was asked about the oversight hearing.

"We talk all the time to the Legislature. I talked to the speaker and the Senate president over the weekend. Marylou does calls at least once a week with both the House and the Senate. We provide them with a lot of information and material, and obviously, we'll look forward to talking to them about this," Baker said then.

Sudders was also working the phones on Thursday talking to lawmakers who have been hearing the vaccine rollout complaints from frustrated constituents.

"I am currently on a call w Secretary Sudders and the rest of the legislature trying to find answers as to what's happening with the website. It's unacceptable," Rep. Smitty Pignatelli of Lenox tweeted on Thursday.

Baker has defended certain decisions that he says led to a slower vaccine rollout than in some other states, including the prioritization of residents and staff at long-term nursing and congregate care facilities, but he has also admitted to being "late" with things like the call center. Even after the call center was set up, it took multiple days and pressure from lawmakers before evening and weekend hours were added.

"My hair's on fire about the whole thing. I can't even begin to tell you how pissed off I am," Baker said Thursday on the radio about Thursday's crash of the appointment website.

The new Committee on COVID-19 and Emergency Preparedness was established this month by Speaker Ron Mariano and Senate President Karen Spilka, signaling a desire on the part of top Democrats to play a more active role in the state's pandemic response, which has largely been run by Baker using a steady wave of executive orders.

Comerford, of Northampton, comes from a background in social work, while Driscoll's area of expertise is disaster response and emergency preparedness. The senator described her and Driscoll's backgrounds as "a good marriage" for the committee.

While the decision to focus right away on the state's vaccination effort was an easy one, according to the two chairs, Driscoll said he does envision the new committee branching out at some point beyond the pandemic.

The Milton Democrat noted that it's been a decade since multiple tornadoes touched down in western Massachusetts, cutting a 40-mile-long swath of damage through Springfield, destroying business and homes.

"That gives us an opportunity to see what do we think we learned 10 years ago after that event and have we applied what we learned," Driscoll said.

Driscoll said he's also spoken with Rep. Dan Hunt, a Dorchester Democrat and the chair of the new Committee on Federal Stimulus and Census Oversight, about ways they could work together.

But for now, the immediate concern is the pandemic and the vaccination effort. Massachusetts through Wednesday had administered 1,267,262 doses of COVID-19 vaccine, including 937,273 first doses, according to DPH.

Over the past week, the administration has highlighted strides the state has made, with about 285,000 doses given last week. Baker has said the state also stacks up well against other states with more than 5 million people, and CDC data puts Massachusetts ninth in the country for first doses administered.

But questions remain about the state's technology, the prioritization plan for vaccines, lines of communication to local boards of health, and the equity -- both racial and geographic -- of vaccine distribution.

"There is a false dichotomy being set up that either we need to move quickly or we need to center equity. We can and should do both," Comerford said. "I do believe the initial vaccine plan had that care at the center and somehow the call for speed has caused Baker to pivot in ways that have forsaken equity. These are false pivots."

Comerford specifically mentioned the "companion" policy that allowed young, healthy residents to get vaccinated if they accompanied someone 75 or older to get a shot, website foibles, and the "abrupt" decision and short notice given to local vaccine clinics that supplies would be redistributed to mass vaccination sites.

"There is a reality when it comes to a shortage at the federal level. That is something we should be talking about clearly, but it's hard to get out that message when there so much state-focused turbulence," she said.

Driscoll said he was particularly frustrated by the rollout of the 2-1-1 call center.

"For me, we all understand that patience is really paramount. The vaccine will still take months to reach many of us. But when we have to pivot over and over again, with very little notice of what's going on to the public and organizations and agencies involved, it begs a lot of questions. The planning for future phases is my concern," Driscoll said.

"We need the next few months to go a lot smoother," Driscoll said.