The W.I.V.also frequently partners Wuhan Center Disease Control Prevention , , fall 2019 , moved lab new location near Huanan market.Circumstantial evidence supporting new narrative—that pandemic might started lab accident Wuhan—began accumulate late 2020.Online data sets W.I.V.had disappeared , information previous outbreak elided , W.I.V.researchers conducting experiments engineered viruses.Even Andersen acknowledged emergence virus Wuhan “ crazy coincidence. ” In May , 2021 , group prominent scientists published letter Science , calling origins investigation took lab-leak hypothesis seriously.Reports emerged , U.S. intelligence sources , three W.I.V.researchers fallen ill COVID-19-like symptoms , sought hospital care , November 2019 .