Some universities say they’ll require their students to be vaccinated for COVID-19 before returning to campus for the fall semester.

Right now, the number of schools implementing this requirement is small, but the list is steadily growing as vaccines become more widely available across the country. President Joe Biden has asked the states to make all American adults eligible for a coronavirus vaccine by April 19.

Below is a running list of schools that have said they’ll require vaccinations; click the links to learn about their specific requirements:

At many of the colleges requiring vaccination, students can request an exemption from for medical or religious reasons. And at some schools, students enrolled in remote or online programs will not be required to get a shot.

While some students enrolled in college may be under 18 and not technically adults, they may still be eligible to receive a Pfizer vaccine, which has been approved to be administered to 16- and 17-year-olds.

Additionally, some of the schools above are requiring their staff members to be vaccinated for the virus.

Nearly every college in the country experienced some kind of disruption due to the pandemic and they were forced to adjust how courses were taken, like through remote learning or smaller class sizes.

These schools hope that by requiring vaccinations, they can limit any COVID-19 outbreaks on their campuses, and they can return to more normal learning environments.