The San Francisco Dept. of Public Health and the Riordan head of school Tim Reardon sent a letter April 27 informing Riordan High School students, staff and parents that TB transmission rates have dropped significantly. The letter stated there would be another smaller round of TB testing May 6-8, to monitor the TB outbreak that was first detected in November 2025. Seven students tested positive for active TB and were undergoing treatment for the bacteria.