New data out of China suggest that 75% of coronavirus patients who were originally classified as asymptomatic went on to develop symptoms of the virus.
The new data, revealed Friday by World Health Organization epidemiologist Maria Van Kerkhove at a Geneva news conference, indicates the difficulty of identifying and tracking asymptomatic patients. It also comes as Chinese data on the coronavirus are being questioned for their accuracy.
Kerkhove urged countries compiling data to separate out those cases of patients who are truly asymptomatic and never go on to develop the virus from those patients who are “pre-symptomatic” — at first having no symptoms and then later developing symptoms of the virus.
Asymptomatic coronavirus patients are infected with the virus and can transmit it to others but have no symptoms of the disease. Identifying and isolating those patients is important to stopping the spread of the disease, according to health officials.
Earlier this week, China released data for the first time on its asymptomatic cases and said it would start including those cases in its official coronavirus count. China had previously excluded those cases from its official public count, leading to incomplete data about the total number of people infected in the country.
U.S. intelligence officials told U.S. media outlets this week that the intelligence community believed China’s public reporting on coronavirus case numbers and deaths was intentionally incomplete.
WHO Health Emergencies Program Executive Director Michael Ryan defended China on Friday against accusations that it was untrustworthy.
“We need to recognize that systems under pressure find it hard to share everything on a minute-to-minute basis,” he said.
On Wednesday, U.S. President Donald Trump said of China’s data reporting, “Their numbers seem to be a little bit on the light side, and I’m being nice when I say that.”