Maryland is offering a $100 incentive for its almost 100,000 state employees to get a COVID-19 vaccine.

“Incentives like this are another way to reinforce the importance of getting vaccinated,” Gov. Larry Hogan said in a statement announcing the program. “We strongly encourage businesses across the state to consider offering incentives to their workers as well.”

State employees who are already vaccinated must provide proof of inoculation to their employer’s Human Resources office to receive their incentive pay. Employees must also agree to receive “all subsequent CDC recommended booster vaccinations” within 18 months of being fully vaccinated.

“Since they are receiving compensation for vaccinations, we want to also encourage them to get booster shots if and when they are needed,” a spokesperson for Maryland’s health department told DCist/WAMU in an email. Employees who receive the incentive but fail to get a recommended booster shot will have to return the $100, the spokesperson said.

Boosters for the existing coronavirus vaccines have not yet been established, though manufacturers with shots authorized in the U.S. have reportedly begun planning for or testing additional shots. The Centers for Disease Control and Prevention says no additional doses are recommended at this time.

More than 62% of Marylanders 18 years and older have received at least one dose of the coronavirus vaccine. More than 35% of the state’s population is fully vaccinated, according to CDC data.