Before arriving at Parris Island, SC, for Marine Corps basic training, potential recruits quarantine at home for 14 days. Next, those deemed mentally and physically suitable for enlistment are quarantined for another 2 weeks under supervision at a closed college campus.
Each class contains 350–450 recruits, subsequently divided into platoons of 50–60 recruits each. Classes arrived at the campus approximately every week, and each had designated housing, with separate training and dining schedules.
Within 48 hours of arrival on campus, 1,848 of the recruits enrolled in the longitudinal COVID-19 Health Action Response for Marines, or CHARM, study. Each participant underwent a baseline antibody test for past exposure to SARS-CoV-2. They then underwent weekly testing for SARS-CoV-2 infection.
During the on-campus quarantine, there was strict enforcement of public healthcare measures. Recruits wore double-layered cloth masks except while sleeping or eating, routinely washed their hands, practiced social distancing of at least 6 feet (2 meters), and remained on the campus, with no access to personal electronics.
The recruits slept in two-person rooms, shared bathrooms with sinks, and ate in communal dining areas. They used bleach wipes to clean their bathrooms after each use, cleaned their rooms daily, and ate pre-plated meals in a dining facility sanitized with bleach after each platoon’s dining period.
Instruction and exercise mostly took place outdoors. Six instructors, assigned to each platoon in 8-hour shifts, supervised unidirectional flow and enforced quarantine measures.
The instructors also stayed on campus, wore masks, and ate pre-plated meals. Neither recruits nor instructors interacted with campus support staff. They also underwent daily temperature checks and symptom screening.
Healthcare staff tested any recruits with symptoms using quantitative polymerase chain reaction (qPCR) tests. Recruits entered isolation pending the results. Instructors underwent rapid qPCR testing for SARS-CoV-2, with removal from duty if any recruit in their platoon tested positive.
Staff cleaned the bathrooms, showers, bedrooms, and hallways in the housing facilities, which remained unoccupied for at least 72 hours after the most recent class had completed quarantine.
Recruits only moved on to Parris Island after having completed the supervised quarantine and receiving a negative PCR test.