If this nun-doctor can’t get a vaccine religious exemption, who can? . Sister Deirdre “Dede” Byrne, POSC. / EWTN News Nightly Washington D.C., Mar 11, 2022 / 08:10 am (CNA). Sister Dierdre Byrne, a Roman Catholic nun who is also a physician-surgeon and a retired U.S. Army colonel, is suing Washington, D.C. for denying her a religious exemption to its COVID-19 vaccination mandate for health care workers. Known as “Sister Dede,” Byrne was an Army doctor who did a three-month tour in Afghanistan as a reservist prior to joining the Sisters of the Little Workers of the Sacred Heart. In Washington, …