WORCESTER, Mass. - It’s hard to believe that the most vaccinated state in the country, Massachusetts, is seeing a third surge of COVID-19.

UMass Memorial president and CEO, Dr. Eric Dickson, says it's frustrating to see another surge of the virus, especially with more than 72% of Massachusetts residents being fully vaccinated.

“This virus mutates at a faster rate than we anticipated originally,” Dr. Dickson said in an interview on Thursday. “It’s finding ways to be even more infectious and that's getting through the protection of the vaccines.”

Dr. Dickson says the delta variant is still causing the biggest increase in hospitalizations. 

“Right now, we have a severe bed shortage in Worcester County and Central Massachusetts,” Dr. Dickson said. “We have about 150 COVID patients hospitalized, taking up 15% of the beds.”

Dr. Dickson says while the vaccine is the best protection to stop the spread of infection and reduce the severity of disease, it's not perfect.

“Almost an ideal situation would be a variant comes out, it's super infectious, but causes mild disease,” Dr. Dickson said. “Then everyone would get immunity from having got it.”

He adds the vaccine's efficacy is reduced over time and expects needing a booster shot every season could become the new normal.

“Early indications are we are going to see a cyclical set of infections come through every year which will require a booster shot like we do with influenza,” Dr. Dickson said.

Dr. Dickson says he doesn't expect to open a field hospital, mostly because of staffing issues.  He says hospitals are going to have to make it work and hopefully keep enough beds running to manage the surge.