One day after claiming the transmission of COVID-19 by people who never develop symptoms is "very rare," the World Health Organization walked back its comments, saying asymptomatic spread is a "really complex question."
Dr. Maria Van Kerkhove, head of WHO's emerging diseases and zoonosis unit, said Tuesday that information pertaining to the spread of coronavirus is still unknown and that she was referring to a small subset of studies when she made her original assessment.
"I was responding to a question at the press conference. I wasn't stating a policy of WHO or anything like that. I was just trying to articulate what we know," she said during a live question and answer session. "And in that, I used the phrase ‘very rare,' and I think that that's misunderstanding to state that asymptomatic transmission globally is very rare."
Kerkhove said studies show that 16% of the population may be asymptomatic, although some models created by other scientists suggest "around 40% of transmission may be due to asymptomatic" individuals.
Dr. Mike Ryan, executive director of the WHO's emergencies program, echoed Kerkhove's comments, saying there is still "much that is unknown" regarding the asymptomatic spread of coronavirus.
"There is much to be answered on this," he said. "It's clear that both symptomatic and asymptomatic individuals are part of the transmission cycle. The question is what is the relative contribution of each group to overall number of cases."