ST. LOUIS (KMOV.com) — St. Louis County health officials say a number of student athletes were infected with COVID-19 after taking part in sports activities.

Officials said five clusters of COVID-19 transmissions were recently documented with a direct link to high school sports practices or games. 

In addition to those cases, officials said more than 20 other student athletes tested positive for COVID-19 in recent weeks but it’s still unclear if transmission happened at an athletic or social activity. 

“The reality is that games in high-contact sports present a risk of transmission,” county officials said in a statement. “Players are within inches of other players, breathing, spitting and yelling without masks. Physical exertion entails heavy breathing, which is known to be a vector of disease spread. And related activities such as team huddles, shared meals, team bus rides, frequent carpooling and crowds of spectators further compound transmission risk.”

On Thursday, Jefferson County health officials announced two football teams went under quarantine after several players tested positive for the virus.