CHINHAE, Republic of Korea (Jan. 7, 2021) Sgt. Sooyong Joe administers the COVID-19 vaccine to Hospital Corpsman 2nd Class Shannon Riffe. Soldiers assigned to the 549th Medical Hospital Center, 65th Medical Brigade administered the COVID-19 vaccine, on a completely voluntary basis, to U.S. Navy Sailors who were identified as front line personnel by their commands. (U.S. Navy photo by Mass Communication Specialist 2nd Class Michael Chen)