The World Health Organization held a press conference on Tuesday [June 9] to clarify a surprising announcement it made a day earlier, in which an epidemiologist said that asymptomatic transmission of the coronavirus was “very rare.”
Maria Van Kerkhove, the WHO’s technical lead on covid-19, said at a news briefing that, “From the data we have, it still seems to be rare that an asymptomatic person actually transmits onward to a secondary individual … It’s very rare.”
Several experts were immediately skeptical. For one, the WHO provided no publicly available data to support that stance, while different types of studies have suggested that asymptomatic transmission plays an important role in the seeding and spread of outbreaks across the world. … Other research has shown that a person may be most infectious, judging by the level of virus shed from their body, right before symptoms appear.
Today, Van Kerkhove and Mike Ryan, executive director of the WHO’s health emergencies program, held a Q&A, which largely addressed questions about their statements from Monday.
Van Kerkhove walked back her earlier wording, saying it was a “misunderstanding” … . She said that her statement to a specific question was based on unpublished research that tried to contract-trace outbreaks as meticulously as possible, including asymptomatic cases. In those investigations, she said, the occurrence of additional cases from an asymptomatic person appeared to be very rare.