A model predicting the progression of the novel coronavirus pandemic produced by researchers at Imperial College London set off alarms across the world and was a major factor in several governments' decisions to lock things down. But a new model from Oxford University is challenging its accuracy. The Oxford research suggests the pandemic is in a later stage than previously thought and estimates the virus has already infected at least millions of people worldwide. In the United Kingdom, which the study focuses on, half the population would have already been infected. If accurate, that would mean transmission began around mid-January and the vast majority of cases presented mild or no symptoms. The head of the study, professor Sunetra Gupta, an Oxford theoretical epidemiologist, said she still supports the U.K.'s decision to shut down the country to suppress the virus. But she also doesn't appear to be a big fan of the work done by the Imperial College team. If her work is accurate, that would likely mean a large swath of the population has built up resistance to the virus. Theoretically, then, social restrictions could ease sooner than anticipated. What needs to be done now, Gupta said, is a whole lot of antibody testing to figure out who may have contracted the virus. Her research team is working with groups from the University of Cambridge and the University of Kent to start those tests for the general population as quickly as possible.