A US Air Force base could have been a coronavirus hotspot, but only 5 trainees got sick. Here's what they did right.

• A US Air Force base in Texas of 10,579 trainees could have been a coronavirus hotspot just like nursing homes and correctional facilities.
• But only five people got sick thanks to interventions including arrival quarantining, social distancing, face coverings, and rapid isolation of symptomatic people.

The worst coronavirus clusters around the US have been in nursing homes, correctional facilities, meatpacking plants, and churches.

That's because the virus thrives in environments where groups of people are living or working in close quarters.

You'd expect to see the same sort of devastation at a Texas US Air Force base with 10,579 trainees. But because of strict social distancing, quarantining, and other measures, only five people there got sick, according to a new report from the Centers for Disease Control and Prevention.

The report looked at the Joint Base San Antonio-Lackland from March 1 to April 18, when these "non-pharmaceutical interventions" were put into place.

About 800 new trainees arrive at the base each week, where they live and train in groups of 50. They sleep in bunks and are never alone in order to enforce accountability.

Despite the base's inherent risks for the virus, which typically spreads via droplets that spray up to six feet when an infected person sneezes, coughs, speaks or sings, the trainees largely avoided sickness.

Basic military training facilities have been proactive since an outbreak of another respiratory virus occurred in one in 2007. Now their setup involves head-to-toe bunk arrangements, regular cleaning of shared equipment, and screenings for respiratory illness, according to the report.

But during the coronavirus outbreak, the base in Texas took other important measures to keep trainees safe.

First, it implemented quarantining, meaning that all new recruits stayed in a separated area of the base for two weeks when they first arrived. Eventually, it stopped accepting recruits from areas of the country with higher rates of COVID-19, the disease caused by the coronavirus.

Trainees were also instructed to practice social distancing by staying at least six feet from others and wearing cloth masks.

The trainees were screened for symptoms, too, and tested if they were suspected to be infected.

During the study period, only five people tested positive, and they were immediately isolated while public health officials conducted contact tracing.

It turned out that three of the five cases were all connected to "patient A," or the first person to test positive on that base. The fifth case seemed to have contracted the virus before he arrived.

None of the men needed to be hospitalized, and all resumed their training, while being carefully monitored, after their symptoms subsided.

While the success of the base in avoiding a massive outbreak of COVID-19 can be attributed to its resources and already highly-structured environment, other settings can learn from its implementation of social distancing, quarantine, and control of the virus at the source.