(CNN)Prisoners in Massachusetts have a special incentive to get the Covid-19 vaccine.
If they receive both doses, watch and read educational materials and submit a form for approval, they could shorten their sentence, the Department of Corrections said in a memo.
The incentive is made possible by a Massachusetts law, which states that prisoners are "eligible to earn deductions from sentences and completion credits, collectively known as good conduct deductions, for participation in and completion of programs and activities" outlined in the law.
That's what Department of Correction Commissioner Carol A. Mici described as "earned good time" (EGT) in a January 28 memo addressed to inmates/patients.
Prisoners who complete the required steps are eligible for a total of seven and a half days of EGT, according to the memo.
"I have determined that receiving the vaccine is significantly valuable to rehabilitation and will therefore be offering Earned Good Time," Mici wrote.
Prisons remain hot spots for Covid-19
Massachusetts is one of only a few states including prisoners in Phase One of its vaccine distribution rollouts.
As of January 28, when the memo was sent out, over 3,500 DOC inmates had received the vaccine, Mici wrote.
Prisons have been hot spots for virus infection from the early days of the pandemic.
According to the Covid Prison Project, which monitors Covid-19 in correctional facilities across the US, there have been 368,271 Covid-19 cases and 2,256 related deaths among incarcerated people to date.
"If we just purely look at the epidemiology of Covid-19 where the outbreaks have been, it's really hard to ignore jails and prisons," Lauren Brinkley-Rubinstein, an assistant professor of social medicine at the University of North Carolina at Chapel Hill and co-founder of the project, told CNN last month. "They've really been the epicenter in many ways."
In December, over 480 health experts signed an open letter urging the CDC advisory group to prioritize incarcerated populations for vaccinations.
Virginia also offers incentives to prisoners
Massachusetts is not the only state to offer incentives to prisoners eligible for vaccination.
The Virginia Department of Corrections announced on January 21 that inmates who receive the vaccine will get "free email stamps and telephone credits" along with packages of commissary items, like snacks.
Incentives besides EGT in Massachusetts have not been announced.