A paper published on 30 January in The New England Journal of Medicine (NEJM) about the first four people in Germany infected with a novel coronavirus made many headlines because it seemed to confirm what public health experts feared: that someone who has no symptoms from infection with the virus, named 2019-nCoV, can still transmit it to others. That might make controlling the virus much harder.
Chinese researchers had previously suggested asymptomatic people might transmit the virus but had not presented clear-cut evidence. “There’s no doubt after reading paper that asymptomatic transmission is occurring,” Anthony Fauci, director of the U.S. National Institute of Allergy and Infectious Diseases, told journalists. “This study lays the question to rest.”
The letter in NEJM described a cluster of infections that began after a businesswoman from Shanghai visited a company near Munich on 20 and 21 January, where she had a meeting with the first of four people who later fell ill. Crucially, she wasn’t sick at the time: “During her stay, she had been well with no sign or symptoms of infection but had become ill on her flight back to China,” the authors wrote. “The fact that asymptomatic persons are potential sources of 2019-nCoV infection may warrant a reassessment of transmission dynamics of the current outbreak.”
But the researchers didn’t actually speak to the woman before they published the paper. The last author, Michael Hoelscher of the Ludwig Maximilian University of Munich Medical Center, says the paper relied on information from the four other patients: “They told us that the patient from China did not appear to have any symptoms.”
