The Chinese Center __1__ Disease Control and Prevention said the conclusion that human-to-human transmission __2__ the novel coronavirus could have occurred as early as mid-December is drawn __3__ a retrospective study based __4__ published cases __5__ the infection. Some people accused researchers and officials __6__ the center __7__ intentionally covering __8__ the risk __9__ transmission __10__ people __11__ of self-interest to gain academic clout. “ The conclusion is a deduction based __12__ a retrospective study that looks back on epidemiology research of infected cases, ” the center said, reaffirming that the risk of the virus spreading among people was not discovered __13__ the onset __14__ the outbreak __15__ December. The center said that information __16__ the 425 cases analyzed __17__ the paper, __18__ infections __19__ 15 medical workers, was already released __20__ the public before researchers set __21__ the study. Evidence __22__ person-to-person transmission __23__ the outbreak was first disclosed __24__ the public __25__ Zhong Nanshan before studies associated __26__ the paper began. The center added that prompt release __27__ research results __28__ the novel coronavirus __29__ academic journals is aimed __30__ sharing the latest information __31__ scientists __32__ China and abroad, joining efforts to evaluate the outbreak and improving control measures.