In the statement WHO noted it appears to be rare that an asymptomatic person transmits the virus. In the truly asymptomatic, symptoms will never develop, and the only way to identify these people is by testing. Circling back to the WHO clarification issued Tuesday, its 16 percent estimate of asymptomatic spread appears to refer specifically to people who are truly asymptomatic. Notably the CDC, in its guidance for developing COVID-19 pandemic models used an estimate of 35 percent of asymptomatic spread and a study published on June 3 in the Annals of Internal Medicine analyzed 16 other reports of asymptomatic spread and estimated it to be as high as 40 to 45 percent, although they could not completely assess what percentage might have been presymptomatic spread. In terms of whether these differences in asymptomatic versus presymptomatic spread change anything right now the answer is simple.