U.S. Navy Hospital Corpsman 2nd Class Quentin Denzel Foley, a preventive medicine technician with the Expeditionary Medical Facility (EMF), prepares the COVID-19 vaccine for use at Camp Lemonnier, Djibouti, Feb. 27, 2021. The vaccine was kept at a frozen state at minus 25 C to minus 15 C and thawed the day of use in order to maintain its viability. (U.S. Air Force photo by Senior Airman Taylor Davis)

A medical member at Camp Lemonnier checks in a COVID-19 vaccine volunteer at Camp Lemonnier, Djibouti, Feb. 27, 2021. The medical team at Camp Lemonnier set up various stations in order to make the vaccination process as efficient, safe and quick as possible. (U.S. Air Force photo by Senior Airman Taylor Davis)

U.S. Army Staff. Sgt. Kristin Zimmerman, a civil affairs team medic with Civil Affairs East Africa, administers the COVID-19 vaccine at Camp Lemonnier, Djibouti, Feb. 27, 2021. Though the vaccine is voluntary, around 1,100 personnel at Camp Lemonnier have now received their first round of the COVID-19 vaccine. (U.S. Air Force photo by Senior Airman Taylor Davis)

U.S. Navy Lt. David Cruz, the preventive medicine department head with the Expeditionary Medical Facility (EMF), prepares the COVID-19 vaccine for use at Camp Lemonnier, Djibouti, Feb. 27, 2021. Medical personnel at Camp Lemonnier administered the first round of the vaccine to around 600 people. (U.S. Air Force photo by Senior Airman Taylor Davis)