China’s top health officials said a sweeping overhaul to its "COVID-zero" playbook was a refinement of rules and not a relaxation of controls, dismissing interpretations that the changes were a step toward living with the virus.

Officials brandished data that showed cutting centralized quarantine for travelers and close contacts to five days would still catch the vast majority of COVID-19 infections, but said a strict attitude toward stamping out infections remains China’s guiding principle.

The changes, which include reining in mass testing and banning local officials from overzealous lockdowns, come from "a better understanding of the virus, and better research and development of vaccines,” deputy head of the National Health Commission Lei Haichao said at a Saturday briefing.