The Air Force Academy has said that four seniors may not be allowed to graduate later this month because they have refused to get vaccinated against COVID-19. In addition, they may have to pay back thousands of dollars in tuition costs.

Air Force Academy spokesman Lt. Col. Brian Maguire said that the four cadets, who were not identified, still have time to change their minds and get vaccinated before the graduation ceremony in two weeks.

While the Pentagon requires all active members of the military to be vaccinated against COVID-19, the Army and Navy have not said if they plan to bar unvaccinated cadets from graduating. It is unclear how those cadets would be able to serve without receiving a COVID-19 vaccine.

The Pentagon said it has received over 20,000 requests for a religious exemption to the vaccine and noted that thousands have been denied. Nearly 98% of soldiers have received at least one dose of a COVID vaccine.

However, more than 4,000 soldiers across all four branches of the military have been discharged for refusing to get vaccinated. The Marines had the most troops discharged with 2,100. The Navy discharged 900 sailors, while 500 Army soldiers and 360 airmen were forced out of the service. In addition, at least 50 service members left during entry-level training.