Dr. Katherine Gergen Barnett returned to Boston Public Radio Monday, offering some clarity on why Massachusetts lags behind the rest of the nation when it comes to the distribution of COVID-19 vaccines.

According to a Washington Post vaccine tracker, the Bay State currently ranks 41st in the nation, with just under seven percent of residents having received their first dose. For comparison, Connecticut has managed to vaccinated almost 10 percent, while West Virginia has managed to get first-doses to close to 11 percent of residents.

The Boston Medical Center official blamed a combination of factors for what she described as “several bottlenecks” in the state’s rollout. These issues include supply constraints, smaller-than-anticipated doses of vaccine per vile in the case of the Pfizer vaccine, and a lower-than-expected outtake among staff at long-term care facilities.

“I think we are all, even those of us in healthcare, are feeling the effects of the rub here,” she said.

Monday’s interview concluded with Gergen Barnett answering listener questions, on topics like vaccine efficacy, the possibility of mobile vaccine clinics, and why you shouldn’t cancel that dentist appointment.

Dr. Katherine Gergen Barnett is the vice chair of Primary Care Innovation and Transformation and Residency Director in the Department of Family Medicine at Boston Medical Center and Boston University Medical School.