Multiple NBA players have tested positive for COVID-19 for a second time.

The CDC defines "reinfection" as a person getting infection, recovering and then later becoming infected again. There are ongoing studies about how long immunity might last, but the CDC says it expects some coronavirus reinfections.

While the NBA has announced more than 100 positive tests since last summer, the actual number is believed to be significantly higher.

Several teams have more than 10 players who have tested positive at some point over the past nine months. There is some uncertainty about the number of actual positive tests there were during the NBA's three-month shutdown.