At least two Massachusetts universities that have been distributing COVID-19 vaccines have had extras, The Boston Globe reported. At one, Northeastern University, the doses are sitting in freezers because the state has asked the university not to vaccinate anyone who is on the current priority list.

After Northeastern vaccinated all of its front-line workers, it still had 2,000 doses left over last week, the Globe reported. When the university informed the state that officials were planning to use the doses on other employees, such as those with medical conditions, the state asked Northeastern to pause. The university would only be permitted to vaccinate those over 75 and wait a few weeks until moving on to others.

“We could have hundreds of vaccinated people walking around, but our hands are tied,” Renata Nyul, spokesperson for Northeastern, told the Globe. “We still believe that because we have the doses, we should move ahead. But we have been persuaded by officials in the [state] COVID command center that we should wait until next week.”

Massachusetts officials did not respond to the Globe’s questions about why Northeastern was asked to slow its rollout.

The source of the surplus appears to be nursing students. When ordering doses from the state, Northeastern included vaccines for its nursing students. When clinics opened, the university learned that most of them were already inoculated at hospitals.

Salem State University also has had extra doses. The university was given 300 by the state but because of canceled appointments has had leftovers. The university has given those doses to employees who may be eligible later.