Philadelphia health officials are reporting a “small but notable” uptick in chickenpox cases linked to outbreaks at two city schools. According to The Philadelphia Inquirer, each outbreak involved fewer than 10 cases, and there is no connection between the two. It's also unclear which factors have contributed to the rise in chickenpox cases. Philadelphia maintains high overall vaccination coverage, with approximately 94% of schoolchildren immune to varicella (commonly called chickenpox), primarily through vaccination. Philadelphia's varicella vaccination rate briefly dipped after the 2020-2021 school year but rebounded to near pre-pandemic levels by 2024-2025, per state data.